There is an old parable: For want of a nail the shoe was lost;
For want of a shoe the horse was lost;
For want of a horse the battle was lost;
For the failure of battle the kingdom was lost—All for the want of a horse-shoe nail.
It seems to quite accurately describe the version of events the Space Ex has officially released to explain the loss of its Falcon 9 in mid flight. Space Ex believes that a bolt failed on a strut assembly that holds down the Ghe COPV's inside of the second stage LOX tank. The failure of one of these bolts set off a chain event that within one second resulted in the overpressurization and explosion of the second stage LOX tank and destroyed the Falcon 9.
After Space Ex was able to triangulate high speed accelerometer data and locate the original "sound" that corresponded in time with the loss of Ghe pressure in the COPV's inside the second stage LOX tank they quickly began conducting tensile strength tests on strut assemblies they had in stock. Although some of these strut assemblies failed at around 6000 pounds of force instead of the rated 10,000 pounds of the strut it still didn't explain how one could have failed at 2000 pounds of force which is the calculated load on the struts and maximum G force during ascent.
Eventually, Space Ex was able to find a bolt for one of these assemblies that failed at 2000 pounds of force. Therefore, they concluded that it was probably a bolt that holds the strut assembly to the tank that actually failed. During subsequent press conferences Elon Musk went into a lot of detail explaining how the strut assembly was not manufactured by Space Ex but was instead specified and bought based upon this manufacturers strength specifications. When pressed by reporters to name the manufacturer Musk declined and explained that it would not help the situation. Musk went on to explain that further metallurgical testing on the bolt itself showed improper grain forging which could have also led to a similar failure on the Falcon 9 that exploded. He seemed to have found the smoking gun for the failure sequence that led to the loss of his rocket.
When asked about the materials that the assembly was made of he also declined to go into details but put forward the information that it was a type of steel and was rated for a much higher failure pressure than it would have ever seen on flight. This is very curious, especially when in the same interview he went on to explain that they were considering going to an inconel material which is much harder to come by and astronomically more expensive to buy and manufacture. In the short term he suggested that they didn't actually test the strut assemblies previous to the loss of this vehicle but would certainly do so in the future. He was careful to explain that they had used the manufacturer's strength rating in lieu of actual testing but that at least one improperly forged bolt had been found in their inventory.
A "type of steel" is a red flag for anyone familiar with cryogenic atmospheres. Carbon steel materials lose all of their tensile strength when exposed to cryogenic temperatures. The immediate embrittlement that such temperatures cause in the granular structure of carbon steel is instantaneous and catostrophic. Just as an example, we experienced a catastrophic failure on a high pressure pipeline because of very short term exposure to LN2 (-320 degrees F). We had a heat exchanger controller failure that led to a small amount of LN2 trickling into the 3" 6000 PSIG pipeline previous to starting pumps to pressurize the system. The pipeline soon violently exploded at less than 200 PSIG in a location where it was in mechanical tension.
Even stainless steels with their lower proportion of carbon lose proportional amounts of tensile strength when exposed to cryogenic temperatures which is why careful control of metallurgy, forging process, and purity is required in all such systems. Different grades of stainless (depending largely on the amount of carbon to nickel composite) have different reactions to such temperatures. What has since become public knowledge is that Space Ex was buying off the shelf strut assemblies from a manufacturer that was not aware of the environment they were to be used in. Space Ex took some standard temperature de-rating tables based upon the assumed metallurgy of the struts they were buying and effectively load rated their strut system by analysis. There is nothing wrong with load rating by analysis as long as strict compliance of material pedigrees are observed but that does not appear to be what happened in this case. Since the manufacturer was not aware that these strut assemblies would be exposed to cryogen temperatures they do not track forging processes and metallurgy necessary to do such de-rating by analysis. This also explains why ultra weight conscious rocket ship designers used 10000 psi rated struts in a 2000 psi application.
As I have already mentioned in this thread, Space Ex has long struggled with configuration control of the hardware they are flying. It is a byproduct of being in a tremendous hurry to launch payloads. To be fair Space Ex is driven to this frenzy by the government that is punishing them monetarily for delays on manifests. Add to that the open competition they find themselves in to gain more launch manifests and you begin to see the extreme pressure they are under to launch vehicles. Under such pressure there is little wonder that they took the shortcut of buying off the shelf hardware and downrating it by analysis. It doesn't make it a good practice but it is understandable.
It doesn't make Musk's claim that a bolt "snuck" through the system accurate. It may have, but the real fault was in using assemblies in environments they were not made to be used in without at least explaining to the supplier that they needed to control the metallurgy and purity to make Space Ex's analysis hold up.
Unfortunately for Space Ex there is no proof that any of this is what caused the loss of the Falcon 9 mid-flight. While such a sequence of events seems to fit most of the data that Space Ex has, there are also parts of this story that do not fit the data. This is why neither NASA's independent investigation signed off on this theory, nor did any of the members of Space Ex's investigation that do not directly work for Space Ex. The broken strut assembly scenario is one of several fault tree sequences that could explain what happened. However, there is at least on major piece of data that most definitely is not explainable by this scenario.
The first actual warning that something was amiss on the Falcon launch was a minor drop in pressure on the Ghe pressure of the COPV's mounted in the second stage LOX tank. Musk's first public statements about the investigation brought out the fact that the data seemed counterintuitive. The data, which was taken at a relatively low rate of speed, showed a drop in pressure followed by a return to "normal" pressure. The transducer that monitored this pressure was mounted on a manifold assembly tied to several of the COPV's in the LOX tank. Through the years of doing this type of work I have been exposed to several instances where the data doesn't seem to match any logical sequence of events. It is frustrating to say the least. At some point it is not unusual in such a case to believe that you may have just found THE exception to the universal laws of physics. Reason always prevails but that thought can occur.
The drop in pressure that Space Ex saw in their data was very short, less than a second, before the overpressurization and rupture of the LOX tank occurred. The best scenario that Space Ex was able to come up with was that the initial "sound" that high speed accelerometer data was used to triangulate to the area of the COPV's seemed to occur at the same time as the drop in pressure. If this was indeed a strut or bolt breaking then the COPV would begin to rapidly rise in the LOX tank, ripping the connecting tubing that attached it to the other COPV's as it moved. Space Ex engineers theorized that the tubing could have kinked and shut off the leaking Ghe for a few milliseconds which would explain the return towards "normal" pressure on the Ghe manifold.
I think we have reached the point described above concerning an exception to the universal laws of physics with this explanation. Or... as a friend I worked with for many years used to explain in a crude way; bull$%^t. He would usually do this quite openly in a feigned sneeze at high volume; bull$%^t as he covered his mouth. In order to understand my incredulous disbelief let me explain a little further.
A water hose can indeed kink in such a manner that you can shut off the flow of water at low pressures. I have even seen brake lines of small diameter kink such that hydraulic fluid can be restricted enough to defeat the balance on a brake system. What I have never seen and will defy anyone to produce is a 5500 PSIG Ghe line that is kinked enough to shut off the leak of Helium. In the configuration that Space Ex uses of their COPV's inside LOX tanks there are several different tanks tied to one tubing manifold. If one tank becomes detached and begins to rapidly rise the line would have to kink in two directions at once for the pressure to return to "normal." It would have to shut off leakage from the rising tank and the tank that it was tubed to at the same time. If one such kink is impossible I don't know how to describe the statistical impossibility that two simultaneous kinks would represent.
There is more....
In the constant effort to save weight Space Ex used titanium tubing to make these manifolds. Titanium is both lighter and stronger than the stainless tubing usually used in such applications so they were able to use extremely thin walled tubing for this assembly. In other words, this tubing has great strength for retaining internal pressure but almost no shear strength to resist tearing apart. If a strut assembly were to break and the COPV to start a rapid ascent in the tank it would immediately tear the tubing apart instantaneously releasing a large volume of helium into a tank with a very small ullage. In other words, the LOX tank would rupture AND there would be no rise in Ghe pressure after the initial drop in pressure.
Add to all of this the fact that all preliminary data suggests that the same type of COPV in the same second stage LOX tank just experienced a "massive breach" that destroyed a second Falcon 9 as it was filled with propellants while sitting on the launch pad and the story gets even harder to believe. Preliminary data also suggests that there was a large drop in pressure followed by a similar rise in pressure in this same Ghe system right before this vehicle exploded.
Is there a scenario that matches this sequence of events? It turns out there is and it isn't counterintuitive at all once you understand the COPV failure mechanism. More on that tomorrow......
Thursday, October 6, 2016
Confusing Data and Assumptions about Metallurgy
On September 1, 2016 a Space Ex Falcon 9 exploded on the pad at Kennedy Space Flight Center. The Falcon was in the process of loading propellants when this explosion occurred. Preliminary reports suggest that a large breach occurred in a helium tank in the upper stage which after some .9 seconds caused the rupture of the LOX tank it was contained within. The resultant fire destroyed much of the Falcon 9 and severely damaged the pad itself.
There is some careful wordsmithing going on at the moment to suggest that this accident has no relationship to the earlier Falcon 9 that exploded in flight but the truth of the matter is that the ultimate destruction of both vehicles was caused by the failure of a helium tank inside the upper stage LOX tank. Space Ex, who had earlier determined that the first loss was caused by the failure of a mounting strut that holds the tank in place during flight, immediately suggested that there is no correlation between the two failures as this strut is not under dynamic load during propellant loading. While this is true, it skips over the fact that only Space Ex believes that it fully understands what happened to the first flight. An independent NASA investigation into the same incident suggests that while the strut issue was a problem, there are several other possibilities that could have caused the same incident. In other words, while everyone agrees that a rapid overpressurization of the LOX tank caused the incident, everyone does NOT agree about what caused the failure of the helium tank that led to this overpressurization.
The first Falcon 9 that exploded in mid-flight was most definitely experiencing dynamic loads that are not present during propellant loading on the pad. Therefore, it is extremely unlikely that a strut failure occurred to cause this explosion. However, it is worth backing up a little bit here to explain how Space Ex decided that the strut failure was actually what caused the first accident.
Early data from the first incident presented some seemingly conflicting and contradictory data. Telemetry system data suggested that there was a very brief drop in Helium pressure immediately previous to the explosion. This would make sense if a tank experienced a sudden leak or breach of some kind but there was also data that suggested that the pressure immediately returned to normal before the actual explosion. Engineers from Space Ex and NASA were confused by this information to say the least.
Early on, Space Ex was concerned about the bouyancy effect of the Helium tanks within the LOX tank. Bouyancy in LOX is little different than bouyancy in water and most everyone understands that holding a balloon underwater is problematic. The same thing occurs in a COPV pressurized with helium in a LOX tank. As the G forces increase during launch the bouyancy increases. In other words, the upward pressure on the struts that hold the helium tanks in place increase as the rocket ascends rapidly. Due to the timing of the incident on the Falcon 9 it seemed that this problem occurred simultaneous with a very high G loading on the flight.
The second clue that led investigators to look at these struts was some acoustic data from microphones/accelerometers on the vehicle. The data from these intruments is taken at a high rate of speed that is inherently necessary to gather vibration data for analysis. As I have discussed in here before (see Update Rates) digital data systems take snapshots of pressure, vibration, and temperatures. These snapshots are taken at varying rates dependent on the type of data you are trying to collect. These snapshots are then arranged on a plot and a line is drawn between the points on the chart to create a graph displaying this information vs. time.
One of the problems with digital data is that is can easily be used to draw graphs that do not resemble actual events. For instance, if you take digital data on a repeating sine wave that operates once a second you can accurately represent this sine wave if you take at least ten snapshots per second. However, if you take only two snapshots in this time period you will wind up with a graph that doesn't even resemble a sine wave. It is accurate data at that point but it completely misrepresents a sine wave. In other words, the snapshots are accurate but the resultant graph is bogus.
There are standard formulas for deciding data rates for all manner of instrumentation which I won't go into here, but it is also dependent on both the instrument you are using to gather the data and the speed of the event you are trying to capture. In the case of the Falcon 9 that exploded in flight the data gathered from the Helium pressurization system was probably rather slow in terms of trying to capture the event that actually happened. I don't know this for a certainty as I have not personally seen the data but a pressure trandsducer that is being used to monitor tank pressure there is typically no need to monitor it at a high rate of speed as the pressure is not expected to change extremely rapidly. If you knew you might want to use it to decide exactly how and when something explodes you would run it at an extremely high rate of speed but that is not what this system was designed and built to do.
Ideally, one would set all such systems up for such an eventuality but running at extremely high rates of speed on numerous channels costs money and if you aren't convinced you will ever need this high speed data you simply don't design systems to accomodate it. When we are purposefully taking COPV's to failure we would typically run our data collection pressure channels at 50,000 Hz. In other words, we would take a snapshot 50,000 times a second so that we could see exactly what the pressure was when the tank ruptured. Gathering 50,000 Hz data is not that difficult with today's systems but storing it and being able to analyze it later can be problematic and expensive.
I suspect from the information I have seen released that the pressure system Space Ex was using on the helium tanks was on the order of 10 hz. Again... I don't know this for certain but it would make sense economically and technically as they were not expecting to see rapid pressure changes in this system to begin with. It would also explain the delay between the drop in pressure and the overpressurization or loss of the vehicle. Even if they were running at 100 hz it is still not fast enough to have a lot of data as to what had actually happened in the helium system.
Space Ex was also running accelerometer/microphone data systems at several locations on the vehicle to monitor vibration during the flight. These types of instruments operate at much higher frequencies inherently because they are looking for vibration signals in the thousands of cycles per second. Using this high frequency information they look for vibrational problems that might create positive feedback loops of resonant frequencies that could damage or destroy the vehicle. This is another problem with space flight that is always a concern. You don't want to set up positive feedback loops that destroy your vehicle. Instrumentation looking for these loops is monitored and systems are throttled specifically to avoid these issues.
Using this high speed data, Space Ex determined that there were two significant incidents that occurred at different times. The first was a significant "sound" or detectable vibration and .9 seconds later the vehicle exploded. By triangulating the various signal locations Space Ex determined that the first "sound" came from the area where the helium tanks were located. This led back to their original concern about the bouyancy of the helium tanks in LOX and how it was affected by the G loading during ascent. If the original "sound" was a strut breaking, the rapid rise of the helium tank in the LOX tank could have followed. The resultant collision with a wall of the LOX tank or the top of the tank would have precipitated the instantaneous failure of the COPV, releasing 5500 PSIG of Helium into the LOX tank and overpressurizing it immediately.
Space Ex began testing mounting struts that they had in stock to see if some of them might fail at lower torque ratings than their specification. What they found was that several of them did fail at much lower ratings than their specification. Meallurgy studies found consistency problems at the granular level in these struts. Steel struts, just like steel bolts are rated for shear strength and manufactured accordingly. The second part of this problem has to do with the fact that they were being used to mount helium tanks inside a LOX tank. If a steel strut has minor inconsistencies in the granular structure but it is highly overrated for shear pressure this is not a problem. Space Ex soon came out and said that some of these struts failed at 5 times lower pressures than they were rated for. They also refused to release the name of the manufacturer of these struts but stated that from this point forward they would individually test each strut before use.
All of this sounds reasonable except for there is no mention of the more important fact that typically carbon steel struts are NEVER used in cryogenic applications. Exposing stainless steel to -297 degrees temperature changes its shear rating dramatically. Minor granular inconsistencies become major catostrophic failures under these conditions, which is why you do not use any type of steel struts in such conditions without comprehensive metallurgical pedigrees. Space Ex has been in a constant running battle with its NASA oversight groups from the beginning of its existance because of its unwillingness to do due diligence on configuration control issues such as this one. When this Falcon 9 exploded in mid-flight there were numerous parts flying on it that Space Ex could not identify as to origin or pedigree. This was not limited to struts, nuts, and bolts but went as far as valves, regulators, and all manner of complex components. In other words, they completely lost configuration control in their haste to launch vehicles on many of the systems on their vehicles. This is a much worse problem than a few struts that failed during testing. It is a problem that will have ever more serious implications in the future if it is not straightened out.
Space Ex used the data it had to locate an issue. The struts they were using to mount these tanks had basic flaws in some of them that could have caused this accident and they absolutely needed to fix this issue before continuing to launch vehicles. Unfortunately, there is no proof that this issue is what caused the loss of the Falcon 9 during flight. It makes a plausible story and it was definitely an issue that needed to be rectified. However, neither any of the investigators on Space Ex's team that did not work for Space Ex nor the independent NASA investigation team were convinced that this was THE cause of the loss of the Falcon 9 on June 29, 2015.
There is some careful wordsmithing going on at the moment to suggest that this accident has no relationship to the earlier Falcon 9 that exploded in flight but the truth of the matter is that the ultimate destruction of both vehicles was caused by the failure of a helium tank inside the upper stage LOX tank. Space Ex, who had earlier determined that the first loss was caused by the failure of a mounting strut that holds the tank in place during flight, immediately suggested that there is no correlation between the two failures as this strut is not under dynamic load during propellant loading. While this is true, it skips over the fact that only Space Ex believes that it fully understands what happened to the first flight. An independent NASA investigation into the same incident suggests that while the strut issue was a problem, there are several other possibilities that could have caused the same incident. In other words, while everyone agrees that a rapid overpressurization of the LOX tank caused the incident, everyone does NOT agree about what caused the failure of the helium tank that led to this overpressurization.
The first Falcon 9 that exploded in mid-flight was most definitely experiencing dynamic loads that are not present during propellant loading on the pad. Therefore, it is extremely unlikely that a strut failure occurred to cause this explosion. However, it is worth backing up a little bit here to explain how Space Ex decided that the strut failure was actually what caused the first accident.
Early data from the first incident presented some seemingly conflicting and contradictory data. Telemetry system data suggested that there was a very brief drop in Helium pressure immediately previous to the explosion. This would make sense if a tank experienced a sudden leak or breach of some kind but there was also data that suggested that the pressure immediately returned to normal before the actual explosion. Engineers from Space Ex and NASA were confused by this information to say the least.
Early on, Space Ex was concerned about the bouyancy effect of the Helium tanks within the LOX tank. Bouyancy in LOX is little different than bouyancy in water and most everyone understands that holding a balloon underwater is problematic. The same thing occurs in a COPV pressurized with helium in a LOX tank. As the G forces increase during launch the bouyancy increases. In other words, the upward pressure on the struts that hold the helium tanks in place increase as the rocket ascends rapidly. Due to the timing of the incident on the Falcon 9 it seemed that this problem occurred simultaneous with a very high G loading on the flight.
The second clue that led investigators to look at these struts was some acoustic data from microphones/accelerometers on the vehicle. The data from these intruments is taken at a high rate of speed that is inherently necessary to gather vibration data for analysis. As I have discussed in here before (see Update Rates) digital data systems take snapshots of pressure, vibration, and temperatures. These snapshots are taken at varying rates dependent on the type of data you are trying to collect. These snapshots are then arranged on a plot and a line is drawn between the points on the chart to create a graph displaying this information vs. time.
One of the problems with digital data is that is can easily be used to draw graphs that do not resemble actual events. For instance, if you take digital data on a repeating sine wave that operates once a second you can accurately represent this sine wave if you take at least ten snapshots per second. However, if you take only two snapshots in this time period you will wind up with a graph that doesn't even resemble a sine wave. It is accurate data at that point but it completely misrepresents a sine wave. In other words, the snapshots are accurate but the resultant graph is bogus.
There are standard formulas for deciding data rates for all manner of instrumentation which I won't go into here, but it is also dependent on both the instrument you are using to gather the data and the speed of the event you are trying to capture. In the case of the Falcon 9 that exploded in flight the data gathered from the Helium pressurization system was probably rather slow in terms of trying to capture the event that actually happened. I don't know this for a certainty as I have not personally seen the data but a pressure trandsducer that is being used to monitor tank pressure there is typically no need to monitor it at a high rate of speed as the pressure is not expected to change extremely rapidly. If you knew you might want to use it to decide exactly how and when something explodes you would run it at an extremely high rate of speed but that is not what this system was designed and built to do.
Ideally, one would set all such systems up for such an eventuality but running at extremely high rates of speed on numerous channels costs money and if you aren't convinced you will ever need this high speed data you simply don't design systems to accomodate it. When we are purposefully taking COPV's to failure we would typically run our data collection pressure channels at 50,000 Hz. In other words, we would take a snapshot 50,000 times a second so that we could see exactly what the pressure was when the tank ruptured. Gathering 50,000 Hz data is not that difficult with today's systems but storing it and being able to analyze it later can be problematic and expensive.
I suspect from the information I have seen released that the pressure system Space Ex was using on the helium tanks was on the order of 10 hz. Again... I don't know this for certain but it would make sense economically and technically as they were not expecting to see rapid pressure changes in this system to begin with. It would also explain the delay between the drop in pressure and the overpressurization or loss of the vehicle. Even if they were running at 100 hz it is still not fast enough to have a lot of data as to what had actually happened in the helium system.
Space Ex was also running accelerometer/microphone data systems at several locations on the vehicle to monitor vibration during the flight. These types of instruments operate at much higher frequencies inherently because they are looking for vibration signals in the thousands of cycles per second. Using this high frequency information they look for vibrational problems that might create positive feedback loops of resonant frequencies that could damage or destroy the vehicle. This is another problem with space flight that is always a concern. You don't want to set up positive feedback loops that destroy your vehicle. Instrumentation looking for these loops is monitored and systems are throttled specifically to avoid these issues.
Using this high speed data, Space Ex determined that there were two significant incidents that occurred at different times. The first was a significant "sound" or detectable vibration and .9 seconds later the vehicle exploded. By triangulating the various signal locations Space Ex determined that the first "sound" came from the area where the helium tanks were located. This led back to their original concern about the bouyancy of the helium tanks in LOX and how it was affected by the G loading during ascent. If the original "sound" was a strut breaking, the rapid rise of the helium tank in the LOX tank could have followed. The resultant collision with a wall of the LOX tank or the top of the tank would have precipitated the instantaneous failure of the COPV, releasing 5500 PSIG of Helium into the LOX tank and overpressurizing it immediately.
Space Ex began testing mounting struts that they had in stock to see if some of them might fail at lower torque ratings than their specification. What they found was that several of them did fail at much lower ratings than their specification. Meallurgy studies found consistency problems at the granular level in these struts. Steel struts, just like steel bolts are rated for shear strength and manufactured accordingly. The second part of this problem has to do with the fact that they were being used to mount helium tanks inside a LOX tank. If a steel strut has minor inconsistencies in the granular structure but it is highly overrated for shear pressure this is not a problem. Space Ex soon came out and said that some of these struts failed at 5 times lower pressures than they were rated for. They also refused to release the name of the manufacturer of these struts but stated that from this point forward they would individually test each strut before use.
All of this sounds reasonable except for there is no mention of the more important fact that typically carbon steel struts are NEVER used in cryogenic applications. Exposing stainless steel to -297 degrees temperature changes its shear rating dramatically. Minor granular inconsistencies become major catostrophic failures under these conditions, which is why you do not use any type of steel struts in such conditions without comprehensive metallurgical pedigrees. Space Ex has been in a constant running battle with its NASA oversight groups from the beginning of its existance because of its unwillingness to do due diligence on configuration control issues such as this one. When this Falcon 9 exploded in mid-flight there were numerous parts flying on it that Space Ex could not identify as to origin or pedigree. This was not limited to struts, nuts, and bolts but went as far as valves, regulators, and all manner of complex components. In other words, they completely lost configuration control in their haste to launch vehicles on many of the systems on their vehicles. This is a much worse problem than a few struts that failed during testing. It is a problem that will have ever more serious implications in the future if it is not straightened out.
Space Ex used the data it had to locate an issue. The struts they were using to mount these tanks had basic flaws in some of them that could have caused this accident and they absolutely needed to fix this issue before continuing to launch vehicles. Unfortunately, there is no proof that this issue is what caused the loss of the Falcon 9 during flight. It makes a plausible story and it was definitely an issue that needed to be rectified. However, neither any of the investigators on Space Ex's team that did not work for Space Ex nor the independent NASA investigation team were convinced that this was THE cause of the loss of the Falcon 9 on June 29, 2015.
Catastrophic Failure
On June 29, 2015 a Space Ex Falcon 9 lifted off from Cape Canaveral on its way for a resupply of Space Station. 2 minutes and 19 seconds into the flight it exploded spectacularly. Space Ex immediately launched an internal investigation as to the causes of the explosion. Shortly afterwards, Space Ex officials began claiming that had astronauts been on board they would have been safely jettisoned in an escape vehicle. At this same time Space Ex began showing videos of safely executed tests conducted on this jettison system at their facilities. While escape vehicles have been touted by NASA and numerous other space agencies as necessary components of a launch vehicle since the original Challenger explosion many years ago, it is by no means appropriate to think that any such vehicle can protect astronauts during an event such as happened to this Space Ex vehicle.
Escape launch vehicles require advance warning of system problems of a long enough time period so that the escape vehicle itself can be outside the deadly shock wave produced by a large explosion. In the case of this Falcon 9 explosion they had less than a second of data to warn them that there was a problem. This is not a long enough time period to activate the jettison of an escape pod and escape the shock wave. It also assumes that an anomaly such as was seen on Falcon 9, the temporary loss of Helium pressure would have initiated such a sequence. I can assure you that it would not initiate such a sequence. Less than one second of data suggesting that there is an unknown and unknowable blip in pressure would NOT be a cause to abort a mission.
Getting back to the explosion itself, Space Ex eventually concluded that the explosion was caused by a rapid overpressurization of the second stage LOX tank. The first stage of Falcon rockets use an array of Merlin engines. The second stage uses one vacuum tuned engine of the same type with a different injector and nozzle type. Once a vehicle escapes Earth's atmosphere and gravity the power requirements for propulsion drop dramatically. One engine is sufficient to propel the vehicle at this stage but it has to be an engine that is more efficient operating in the perfect vacuum of space. NASA utilizes Hydrogen/LOX engines in this atmosphere because of the increased specific impulse energy over a RP1/LOX engine. For simplicity and the elimination of different fuel storage and handling techniques Space Ex early on opted for RP1/LOX engines for both stages of their vehicles. It is a trade off between efficiency and weight, which is at the root of all such decisions concerning space vehicles.
In order to support combustion of a powerful rocket engine you must have a very fast and efficient pumping system to provide it with the massive amounts of fuel required to produce the high thrust requirements of such a vehicle. Turbopumps have long been a source of problems in this chain. Turbopumps on LOX systems are specifically very problematic because of a couple of inherent features. A turbopump runs at extremely high rates of speed with very close tolerances. As I mentioned before, LOX systems preclude the use of lubricants because of the incompatability of LOX to hydrocarbons. Therefore, you wind up with tight tolerances at extremely cold temperatures that have to self lubricate with the LOX itself. Every rocket manufacturer has struggled with this architecture. As I will explain later, it was this same type of system that was at the heart of the Antarres explosion earlier in this same year.
One of the ways of alleviating this problem is to run the initial tank pressures at high pressures to begin with. This becomes somewhat problematic in smaller tanks as it requires a finely tuned pressurization system to balance the ullage (gas pocket) that sits on top of the liquid with the rapidly depleting liquid in the tank when the engine is firing. Falcon 9 uses gaseous helium to provide the pressurization in their LOX tank on the second stage. Compressed helium is stored in several small pressure bottles inside the LOX tank itself at 5500 PSIG.
In order to give a relative idea of what this type of pressure is capable of think of the movie Jaws where in the last scene the shark is blown up by shooting a rifle into a scuba tank inside his mouth. Scuba tanks are pressurized with breathing air to a little less than 3000 PSIG. As you might imagine such high pressures require a very thick and heavy tank wall so that the vessel itself won't rupture inadvertently from this internal force. As I have mentioned already, the crucial tradeoff in space flight is always weight vs. safety. Instead of 4-1 safety factors such as a scuba tank on earth requires, space vehicles use 1.4 - 1.5 to one as a basic safety requirement. Instead of a tank that operates at 5500 PSIG being required to be designed to withstand 22000 PSIG it is designed to withstand 7700 PSIG.
Space Ex is also doing several other things with this system to increase efficiency. The first thing they are doing is super cooling the helium tank and fill gas by storing it inside the LOX tank itself. This is not a new discovery as NASA has been doing this for quite some time on many different vehicles. By putting the pressurization tank inside the LOX itself it is possible to have a smaller pressurization tank. A tank at 5500 PSIG Helium in ambient temperature will contain much less actual usable gas than a tank containing 5500 PSIG at -279 Degrees F. The Helium molecules become denser and can be more efficiently compressed so that more gas is available to pressurize the tank.
Falcon 9's system utilizes the engine itself to heat the helium and rapidly expand it before returning it to the LOX tank ullage to pressurize the LOX system. The helium is released through chambers in the engine as it burns which rapidly expands the helium before it is returned to the LOX tank to be used as a pressurization source to force the LOX out of the tank and into the engine. As you can imagine, the control system needed to tightly control the ullage at a constant pressure utilizing this chain of events is quite complicated.
Naturally, Falcon 9's LOX system is as full as possible prior to flight. A large initial ullage would require a large tank and more weight so at launch the ullage in the LOX tank is very small. This effectively means that relatively small loss of control of this pressurization system will result in large pressure fluctuations in the LOX tank during the initial use of this system. Rapid pressure rise from uncontrolled release of the Helium in these tanks has resulted in the loss of both Falcon rockets that have exploded so far. We know it did with the first Falcon explosion and all evidence points in the direction that it did on this last one as well.
Before we go any further on this concept let me get back to the other thing that Space Ex is doing with their helium pressurization system. Remember the analogy of the scuba tank for a moment. Not only is Space Ex using a 1.4-1 safety factor on the design of the tanks to be used in but they are also using some relatively new technology to build the tanks themselves. Composite Overwrap Pressure Vessels (COPV's) have been under development for some time now. We have built and tested to failure many such vessels where I work so I am not exactly unfamiliar with the concept.
A COPV can be manufactured in several different ways. Most of them utilize a lightweight inner aluminum tank that is rated at a very low pressure. It is thin walled aluminum and extremely lightweight in comparison with an equal stainless steel tank of the same size. This thin walled aluminum tank is then wrapped with carbon fiber, usually by an automated computer controlled lathe in numerous layers of thin carbon wires that are glued in place as the wrap process takes place. The resultant tank is then tested for pressure rating. Design processes and computer programs to produce these tanks are complicated to say the least.
The end result is a pressure vessel that is vastly lighter, which makes it ideal for usage on space flight vehicles. We have tested design and process on these tanks for many years in our shop. Properly done and controlled such processes produce reliable and predictable results. We have tested series of tanks to failure at Liquid Nitrogen Temperatures (-320 degrees F) and even up to Liquid Helium Temperatures (-452 Degrees F). NASA has entertained the idea of using these tanks just as Space Ex currently does in LOX tanks. They have even considered doing the same thing in Liquid Hydrogen tanks which is why we tested at even colder temperatures.
The key to the successful production of such tanks is process control. In other words, careful control of materials and manufacturing process produces consistent results in the actual pressure these tanks will withstand. Any loss of control of either of these variables produces disastrous results which is why NASA is still reluctant to commit to using COPV's inside LOX and LH2 tanks.
There are at least two other dangers associated with COPV's and their usage. Each pressure cycle effectively stretches the composite overwrap strands to a certain extent. Therefore, COPV's are listed for usage by the number of pressure cycles they see as a matter of course. Each pressure cycle is noted and logged and after a sufficient number of cycles the tank is no longer rated for use as a pressure vessel. By itself, this is not a problem for the usage of COPV's on space vehicles as they will see a relatively small number of usages anyway.
The last part of this issue is that COPV's are extremely fragile as far as handling and usage in comparison with metal tanks. Since the thin composite strands are effectively a very large chain reaction system, any external damage to a small strand effectively makes it the weakest link in a chain and we all know the adage about the weakest link in any chain being the source of its strength. Inadvertent bumping into sharp objects or dropping of objects on COPV's can cause catastrophic failures accordingly.
Escape launch vehicles require advance warning of system problems of a long enough time period so that the escape vehicle itself can be outside the deadly shock wave produced by a large explosion. In the case of this Falcon 9 explosion they had less than a second of data to warn them that there was a problem. This is not a long enough time period to activate the jettison of an escape pod and escape the shock wave. It also assumes that an anomaly such as was seen on Falcon 9, the temporary loss of Helium pressure would have initiated such a sequence. I can assure you that it would not initiate such a sequence. Less than one second of data suggesting that there is an unknown and unknowable blip in pressure would NOT be a cause to abort a mission.
Getting back to the explosion itself, Space Ex eventually concluded that the explosion was caused by a rapid overpressurization of the second stage LOX tank. The first stage of Falcon rockets use an array of Merlin engines. The second stage uses one vacuum tuned engine of the same type with a different injector and nozzle type. Once a vehicle escapes Earth's atmosphere and gravity the power requirements for propulsion drop dramatically. One engine is sufficient to propel the vehicle at this stage but it has to be an engine that is more efficient operating in the perfect vacuum of space. NASA utilizes Hydrogen/LOX engines in this atmosphere because of the increased specific impulse energy over a RP1/LOX engine. For simplicity and the elimination of different fuel storage and handling techniques Space Ex early on opted for RP1/LOX engines for both stages of their vehicles. It is a trade off between efficiency and weight, which is at the root of all such decisions concerning space vehicles.
In order to support combustion of a powerful rocket engine you must have a very fast and efficient pumping system to provide it with the massive amounts of fuel required to produce the high thrust requirements of such a vehicle. Turbopumps have long been a source of problems in this chain. Turbopumps on LOX systems are specifically very problematic because of a couple of inherent features. A turbopump runs at extremely high rates of speed with very close tolerances. As I mentioned before, LOX systems preclude the use of lubricants because of the incompatability of LOX to hydrocarbons. Therefore, you wind up with tight tolerances at extremely cold temperatures that have to self lubricate with the LOX itself. Every rocket manufacturer has struggled with this architecture. As I will explain later, it was this same type of system that was at the heart of the Antarres explosion earlier in this same year.
One of the ways of alleviating this problem is to run the initial tank pressures at high pressures to begin with. This becomes somewhat problematic in smaller tanks as it requires a finely tuned pressurization system to balance the ullage (gas pocket) that sits on top of the liquid with the rapidly depleting liquid in the tank when the engine is firing. Falcon 9 uses gaseous helium to provide the pressurization in their LOX tank on the second stage. Compressed helium is stored in several small pressure bottles inside the LOX tank itself at 5500 PSIG.
In order to give a relative idea of what this type of pressure is capable of think of the movie Jaws where in the last scene the shark is blown up by shooting a rifle into a scuba tank inside his mouth. Scuba tanks are pressurized with breathing air to a little less than 3000 PSIG. As you might imagine such high pressures require a very thick and heavy tank wall so that the vessel itself won't rupture inadvertently from this internal force. As I have mentioned already, the crucial tradeoff in space flight is always weight vs. safety. Instead of 4-1 safety factors such as a scuba tank on earth requires, space vehicles use 1.4 - 1.5 to one as a basic safety requirement. Instead of a tank that operates at 5500 PSIG being required to be designed to withstand 22000 PSIG it is designed to withstand 7700 PSIG.
Space Ex is also doing several other things with this system to increase efficiency. The first thing they are doing is super cooling the helium tank and fill gas by storing it inside the LOX tank itself. This is not a new discovery as NASA has been doing this for quite some time on many different vehicles. By putting the pressurization tank inside the LOX itself it is possible to have a smaller pressurization tank. A tank at 5500 PSIG Helium in ambient temperature will contain much less actual usable gas than a tank containing 5500 PSIG at -279 Degrees F. The Helium molecules become denser and can be more efficiently compressed so that more gas is available to pressurize the tank.
Falcon 9's system utilizes the engine itself to heat the helium and rapidly expand it before returning it to the LOX tank ullage to pressurize the LOX system. The helium is released through chambers in the engine as it burns which rapidly expands the helium before it is returned to the LOX tank to be used as a pressurization source to force the LOX out of the tank and into the engine. As you can imagine, the control system needed to tightly control the ullage at a constant pressure utilizing this chain of events is quite complicated.
Naturally, Falcon 9's LOX system is as full as possible prior to flight. A large initial ullage would require a large tank and more weight so at launch the ullage in the LOX tank is very small. This effectively means that relatively small loss of control of this pressurization system will result in large pressure fluctuations in the LOX tank during the initial use of this system. Rapid pressure rise from uncontrolled release of the Helium in these tanks has resulted in the loss of both Falcon rockets that have exploded so far. We know it did with the first Falcon explosion and all evidence points in the direction that it did on this last one as well.
Before we go any further on this concept let me get back to the other thing that Space Ex is doing with their helium pressurization system. Remember the analogy of the scuba tank for a moment. Not only is Space Ex using a 1.4-1 safety factor on the design of the tanks to be used in but they are also using some relatively new technology to build the tanks themselves. Composite Overwrap Pressure Vessels (COPV's) have been under development for some time now. We have built and tested to failure many such vessels where I work so I am not exactly unfamiliar with the concept.
A COPV can be manufactured in several different ways. Most of them utilize a lightweight inner aluminum tank that is rated at a very low pressure. It is thin walled aluminum and extremely lightweight in comparison with an equal stainless steel tank of the same size. This thin walled aluminum tank is then wrapped with carbon fiber, usually by an automated computer controlled lathe in numerous layers of thin carbon wires that are glued in place as the wrap process takes place. The resultant tank is then tested for pressure rating. Design processes and computer programs to produce these tanks are complicated to say the least.
The end result is a pressure vessel that is vastly lighter, which makes it ideal for usage on space flight vehicles. We have tested design and process on these tanks for many years in our shop. Properly done and controlled such processes produce reliable and predictable results. We have tested series of tanks to failure at Liquid Nitrogen Temperatures (-320 degrees F) and even up to Liquid Helium Temperatures (-452 Degrees F). NASA has entertained the idea of using these tanks just as Space Ex currently does in LOX tanks. They have even considered doing the same thing in Liquid Hydrogen tanks which is why we tested at even colder temperatures.
The key to the successful production of such tanks is process control. In other words, careful control of materials and manufacturing process produces consistent results in the actual pressure these tanks will withstand. Any loss of control of either of these variables produces disastrous results which is why NASA is still reluctant to commit to using COPV's inside LOX and LH2 tanks.
There are at least two other dangers associated with COPV's and their usage. Each pressure cycle effectively stretches the composite overwrap strands to a certain extent. Therefore, COPV's are listed for usage by the number of pressure cycles they see as a matter of course. Each pressure cycle is noted and logged and after a sufficient number of cycles the tank is no longer rated for use as a pressure vessel. By itself, this is not a problem for the usage of COPV's on space vehicles as they will see a relatively small number of usages anyway.
The last part of this issue is that COPV's are extremely fragile as far as handling and usage in comparison with metal tanks. Since the thin composite strands are effectively a very large chain reaction system, any external damage to a small strand effectively makes it the weakest link in a chain and we all know the adage about the weakest link in any chain being the source of its strength. Inadvertent bumping into sharp objects or dropping of objects on COPV's can cause catastrophic failures accordingly.
Wednesday, October 5, 2016
Inherent Issues and Reasonable Response
https://www.yahoo.com/finance/news/house-republicans-just-launched-political-232200411.html
From the article....
3. Given the two recent failures of the Falcon 9, will the Air Force add more weight to mission assurance and schedule reliability vs. price in their future launch service procurements? If not please explain.
First off.... let me start out by saying that the investigation is still underway and no one knows for certain what happened to cause the Falcon rocket to explode on the pad during fueling operations on the pad at Cape Canaveral as of yet.
However, what we do know is that it did explode. Preliminary investigation reports indicate that it was a massive rupture of a Ghe vessel in the second stage LOX tank on the vehicle. Space Ex has been quick to point out that this is NOT the same issue that caused the spectacular mid air explosion on the first Falcon loss less than a year ago. At best, this is a partial truth. At worst, we may soon find that it has an identical cause in the very near future.
Having been personally involved in similar accident investigations in the past, I can say that the whole process of building a fault tree of possible causes and carefully and painstakingly running every possible cause to ground is a slow and painstaking process; especially when much of the evidence is no longer existing due to the inherent dangers that come with using a perfect oxidizer. LOX is Liquid Oxygen and it is the perfect oxidizer of which I am speaking.
LOX is necessary on rocket engines flying out of the earth's atmosphere for a couple of reasons, the main one being that all combustion requires oxygen to support it and once a vehicle is it out of the earth's atmosphere it cannot burn the oxygen in the surrounding atmosphere because there is none. Therefore, there must by an oxidizer on board and LOX is the most efficient oxidizer known to man. Since rocket engines are all about efficiency; ie.... weight to lift capacity on very narrow margins of failure.... LOX is a necessary evil when it comes to launching vehicles out of the earth's atmosphere.
As I have discussed before, the dangers inherent in using LOX are numerous and manifold in nature. It is a cryogen, operating at -297 degrees fahrenheit in it's liquid or condensed version. Exposed to anything above this temperature it will begin to boil with rapid explosive expansion on the order of 861-1 as it changes from a liquid to a gas. LOX is intolerant of hydrocarbons; such that even small traces of almost all known lubricants can cause instantaneous ignition on contact with LOX under almost any pressure at all.
Add just these two inherent conditions alone and you begin to see the difficulty in working with LOX. Since materials naturally tend to contract and shrink as temperatures drop close tolerances on rotating parts such as pumps needed to move LOX become problematic to lubricate effectively. Add in pressures often in the thousands of PSIG necessary to feed and sustain a rocket engine and the problems become infinitely greater.
LOX itself is inflammable. However, being the perfect oxidizer it strongly supports combustion on any type of fuel. It is such a strong supporter of combustion that it makes readily combustible fuels out of things that are normally imflammable. This includes but is not limited to the containment vessels used to store LOX. High grade 316 Stainless steel itself burns readily in such an oxygen rich environment.
As any boy scout can tell you, the basic fire "triangle" necessary to support combustion requires three things. Fuel, Oxidizer, and ignition source. In any LOX system you have two of the three present at all times. The perfect oxidizer (LOX, often at high pressure in our application) and abundant fuel (the storage vessel AND the vehicle structure in our case). All that is between a LOX system and utter catastrophe on a space vehicle is an ignition source.
Anyone who wants to see what a LOX fire looks like can easily look up both recent Falcon infernos, the Antarres accident last year, or any number of other accidents involving space vehicles that NASA has lost in the past. Much of the evidence of what caused the accident is consumed in the inferno that results from the introduction of an ignition source. However, the charred remains plus existing recorded data can tell the story of what happened if considered in enough detail. We have been quite successful in detailing such causes in the past and I expect we will this time as well.
As the letter in the above article points out, we do have some basic problems in both this investigation and the previous investigation of the Falcon vehicle losses. The first and most glaring problem is that both accident investigations were ran by and controlled by the same private entity that created the vehicle. I would also point out that this same entity, necessarily in an ultracompetitive environment, has a vested interest in coming to a rapid conclusion so that it can get back to the business of making money by launching payloads. This inherent conflict of interest should preclude the possibility that Space Ex heads up its own investigation that will determine when they get back into profitable operation.
Unfortunately, this basic common sense idea seems to be overridden in the present situation just as it was in the last investigation into the loss of a Space Ex vehicle. I would also point out that the something similar just happened in the investigation of the Antarres rocket belonging to Orbital Sciences the exploded shortly after liftoff in Wallops, Virginia last year. Having been personally involved in that investigation, I can assure you that this inherent conflict of interest not only hindered the investigation that NASA's oversight group performed; but eventually precluded the possibility of completely understanding the root cause of the loss of that particular vehicle (more on that a little later).
From the article....
3. Given the two recent failures of the Falcon 9, will the Air Force add more weight to mission assurance and schedule reliability vs. price in their future launch service procurements? If not please explain.
First off.... let me start out by saying that the investigation is still underway and no one knows for certain what happened to cause the Falcon rocket to explode on the pad during fueling operations on the pad at Cape Canaveral as of yet.
However, what we do know is that it did explode. Preliminary investigation reports indicate that it was a massive rupture of a Ghe vessel in the second stage LOX tank on the vehicle. Space Ex has been quick to point out that this is NOT the same issue that caused the spectacular mid air explosion on the first Falcon loss less than a year ago. At best, this is a partial truth. At worst, we may soon find that it has an identical cause in the very near future.
Having been personally involved in similar accident investigations in the past, I can say that the whole process of building a fault tree of possible causes and carefully and painstakingly running every possible cause to ground is a slow and painstaking process; especially when much of the evidence is no longer existing due to the inherent dangers that come with using a perfect oxidizer. LOX is Liquid Oxygen and it is the perfect oxidizer of which I am speaking.
LOX is necessary on rocket engines flying out of the earth's atmosphere for a couple of reasons, the main one being that all combustion requires oxygen to support it and once a vehicle is it out of the earth's atmosphere it cannot burn the oxygen in the surrounding atmosphere because there is none. Therefore, there must by an oxidizer on board and LOX is the most efficient oxidizer known to man. Since rocket engines are all about efficiency; ie.... weight to lift capacity on very narrow margins of failure.... LOX is a necessary evil when it comes to launching vehicles out of the earth's atmosphere.
As I have discussed before, the dangers inherent in using LOX are numerous and manifold in nature. It is a cryogen, operating at -297 degrees fahrenheit in it's liquid or condensed version. Exposed to anything above this temperature it will begin to boil with rapid explosive expansion on the order of 861-1 as it changes from a liquid to a gas. LOX is intolerant of hydrocarbons; such that even small traces of almost all known lubricants can cause instantaneous ignition on contact with LOX under almost any pressure at all.
Add just these two inherent conditions alone and you begin to see the difficulty in working with LOX. Since materials naturally tend to contract and shrink as temperatures drop close tolerances on rotating parts such as pumps needed to move LOX become problematic to lubricate effectively. Add in pressures often in the thousands of PSIG necessary to feed and sustain a rocket engine and the problems become infinitely greater.
LOX itself is inflammable. However, being the perfect oxidizer it strongly supports combustion on any type of fuel. It is such a strong supporter of combustion that it makes readily combustible fuels out of things that are normally imflammable. This includes but is not limited to the containment vessels used to store LOX. High grade 316 Stainless steel itself burns readily in such an oxygen rich environment.
As any boy scout can tell you, the basic fire "triangle" necessary to support combustion requires three things. Fuel, Oxidizer, and ignition source. In any LOX system you have two of the three present at all times. The perfect oxidizer (LOX, often at high pressure in our application) and abundant fuel (the storage vessel AND the vehicle structure in our case). All that is between a LOX system and utter catastrophe on a space vehicle is an ignition source.
Anyone who wants to see what a LOX fire looks like can easily look up both recent Falcon infernos, the Antarres accident last year, or any number of other accidents involving space vehicles that NASA has lost in the past. Much of the evidence of what caused the accident is consumed in the inferno that results from the introduction of an ignition source. However, the charred remains plus existing recorded data can tell the story of what happened if considered in enough detail. We have been quite successful in detailing such causes in the past and I expect we will this time as well.
As the letter in the above article points out, we do have some basic problems in both this investigation and the previous investigation of the Falcon vehicle losses. The first and most glaring problem is that both accident investigations were ran by and controlled by the same private entity that created the vehicle. I would also point out that this same entity, necessarily in an ultracompetitive environment, has a vested interest in coming to a rapid conclusion so that it can get back to the business of making money by launching payloads. This inherent conflict of interest should preclude the possibility that Space Ex heads up its own investigation that will determine when they get back into profitable operation.
Unfortunately, this basic common sense idea seems to be overridden in the present situation just as it was in the last investigation into the loss of a Space Ex vehicle. I would also point out that the something similar just happened in the investigation of the Antarres rocket belonging to Orbital Sciences the exploded shortly after liftoff in Wallops, Virginia last year. Having been personally involved in that investigation, I can assure you that this inherent conflict of interest not only hindered the investigation that NASA's oversight group performed; but eventually precluded the possibility of completely understanding the root cause of the loss of that particular vehicle (more on that a little later).
Commercial Space Problems
I am a little disgusted at the moment. The recent explosion at Cape Canaveral is the last in a string of accidents on commercial space ventures that were completely avoidable. It is way too premature for anyone to know what caused this one yet but recent experience has taught me that the cause will once again be found to be schedule haste combined with the reckless and deadly nature of commercial space.
I have written about NASA's accidents and how they were all caused by this same problem before. Schedule pressure is dangerous in the space flight industry. It has to be offset by the understanding that technical concerns ALWAYS overrides schedule pressure. This is literally impossible in commercial space because there is nothing that counterbalances schedule pressure in commercial space. Combine this with a total lack of practical experience that prevails at most commercial space companies and you get what we have now; a continuing string of disasters.
In the first place space flight travel is hard. It takes extremely powerful engines to lift cargo out of earth's orbit. These engines need oxidizers such as liquid oxygen to burn at the rates needed and liquid oxygen is an extremely unforgiving substance to deal with. Because of the energy involved and the close ratio between energy available and load to be lifted space flight vehicles operate on the bare margins of safety to begin with. The standard pressure to strength ratio for mechanical facilities on earth is 4-1. In other words if a tank is designed to withstand 100 pounds of pressure per inch it is designed to withstand 400 pounds of pressure per inch. On a space vehicle, this same tank is designed to withstand 150 pounds of pressure per inch, or 1.5-1.
Add in the extreme temperature changes involved in using a cryogen like Liquid Oxygen (-297 Degrees F) and one can begin to understand the difficulties involved. Each component is designed on the ragged edge of strength to weight ratio to maximize the effective cargo that such a vehicle can carry. Why not just go to 4-1 safety factors you might ask? Well, if we did that we wouldn't have the energy to get out of earth's orbit.
NASA has a long record of dealing with these margins yet they have also experienced many different failures of their own in its own history. Besides the two shuttle disasters that everyone is familiar with there were a lot of other accidents in testing and design phases at different NASA centers across the nation. It is an inherently dangerous business that requires inherently stringent testing and design characteristics. I think everyone understands this. Unfortunately, the degree of stringency is where the argument comes in.
There is a huge disagreement on this at the moment within the commercial space industry. NASA is charged with oversight on commercial space entities and I can tell you from direct experience NASA is losing the argument at the moment. Commerical space entities have a lot of Congressional support from local districts where these ventures are benefitting the local economy with good paying jobs. Hence the continuing level of confidence and support from Congress espousing the full confidence in these ventures. I can assure you that this level of confidence is NOT being expressed by NASA employees charged with actually doing the oversight.
In the next few posts I hope to go over some details about why these problems are occurring and what the particular problems are. The basic struggle is between the technical experts at NASA who have experienced these problems in the past and a young, energetic group working private space who believe NASA is hopelessly slow and restrictive by its very nature. Neither group is completely wrong in their assumptions about the other. However, the reason that NASA is slow and restrictive is that they have already learned some of the lessons that commercial space is struggling with now.
I have written about NASA's accidents and how they were all caused by this same problem before. Schedule pressure is dangerous in the space flight industry. It has to be offset by the understanding that technical concerns ALWAYS overrides schedule pressure. This is literally impossible in commercial space because there is nothing that counterbalances schedule pressure in commercial space. Combine this with a total lack of practical experience that prevails at most commercial space companies and you get what we have now; a continuing string of disasters.
In the first place space flight travel is hard. It takes extremely powerful engines to lift cargo out of earth's orbit. These engines need oxidizers such as liquid oxygen to burn at the rates needed and liquid oxygen is an extremely unforgiving substance to deal with. Because of the energy involved and the close ratio between energy available and load to be lifted space flight vehicles operate on the bare margins of safety to begin with. The standard pressure to strength ratio for mechanical facilities on earth is 4-1. In other words if a tank is designed to withstand 100 pounds of pressure per inch it is designed to withstand 400 pounds of pressure per inch. On a space vehicle, this same tank is designed to withstand 150 pounds of pressure per inch, or 1.5-1.
Add in the extreme temperature changes involved in using a cryogen like Liquid Oxygen (-297 Degrees F) and one can begin to understand the difficulties involved. Each component is designed on the ragged edge of strength to weight ratio to maximize the effective cargo that such a vehicle can carry. Why not just go to 4-1 safety factors you might ask? Well, if we did that we wouldn't have the energy to get out of earth's orbit.
NASA has a long record of dealing with these margins yet they have also experienced many different failures of their own in its own history. Besides the two shuttle disasters that everyone is familiar with there were a lot of other accidents in testing and design phases at different NASA centers across the nation. It is an inherently dangerous business that requires inherently stringent testing and design characteristics. I think everyone understands this. Unfortunately, the degree of stringency is where the argument comes in.
There is a huge disagreement on this at the moment within the commercial space industry. NASA is charged with oversight on commercial space entities and I can tell you from direct experience NASA is losing the argument at the moment. Commerical space entities have a lot of Congressional support from local districts where these ventures are benefitting the local economy with good paying jobs. Hence the continuing level of confidence and support from Congress espousing the full confidence in these ventures. I can assure you that this level of confidence is NOT being expressed by NASA employees charged with actually doing the oversight.
In the next few posts I hope to go over some details about why these problems are occurring and what the particular problems are. The basic struggle is between the technical experts at NASA who have experienced these problems in the past and a young, energetic group working private space who believe NASA is hopelessly slow and restrictive by its very nature. Neither group is completely wrong in their assumptions about the other. However, the reason that NASA is slow and restrictive is that they have already learned some of the lessons that commercial space is struggling with now.
Wednesday, September 7, 2016
The Real Problem with NASA
Many years ago when I first went to work on a NASA facility I was amazed at the complexity of their testing programs. There is an old saying about rocket science that inversely describes the complexity of rocket design by claiming that (insert the field here) is “not rocket science.” It’s not unusual in Huntsville to see bumper stickers that proudly proclaim “Actually…. I AM a rocket scientist.” Putting things into space and maintaining them there is hard. It is complicated and the environment is unforgiving of mistakes.
NASA learned early that small mistakes and minor miscalculations lead to large disasters. Throughout the early years we learned at an accelerated pace that we must minimize the unknowns and maximize the testing to cover every possible variable. Vehicle designs are redundant for all critical failure possibilities. We simply can’t afford to lose a vehicle, more especially a vehicle with people on board because of one component failure especially when we understand that there are a vast number of components in each vehicle.
I was not working at NASA when the Challenger accident occurred but I was here when the Columbia accident occurred. One basic cultural problem led to both failures; schedule pressure overrode technical concerns. It really is that simple. NASA works off of an annually renewable budget that has to be approved by Congress. It is a special executive branch agency similar to the CIA in that the president appoints the director and largely controls its main directives. The head of the agency is approved by the Senate and the budget is controlled by Congress.
Both Shuttle disasters were caused by schedule pressure that was brought to bear based upon funding concerns. NASA’s funding is a political football that is regularly booted about when it comes time to pass a federal budget. At its funding peak during the Apollo buildup NASA received about 4% of the federal budget. In 1975 this fell to below 1% where it has remained since that time. In the early 2000’s it began falling again to the point where by 2012 it has fell below .5%. It has languished there since that time.
The schedule pressure that caused the accidents came from trying to meet projections that had been agreed to with Congress. NASA has learned by experience that delays and slips of projected schedules come at a dear expense. Congress regularly defunds programs that fall behind schedule. NASA reacts by doing the same thing on a smaller scale. When a large program falls behind projected schedule, small programs are defunded on a regular basis.
As the Columbia Accident Investigation Board (CAIB) report that came out after Columbia crashed points out, it is this schedule pressure that led to this accident and the Challenger accident before. Unfortunately, we seem to have taken this report and concentrated on the technical aspects of what caused the actual vehicle to crash without fully comprehending that the larger budgetary concerns are what led to the decision making process that crashed Columbia. In other words, it wasn’t a technical issue that caused the accident; but rather a whole series of decisions before and after the technical issue that were overwhelmingly driven by budgetary concerns at the top levels of NASA.
There is a smoking gun involved but it was loaded, primed, and fired by a budgetary weakness at the heart of NASA’s existence. Annually renewable budgets based upon projections of research and development are inherently inaccurate entities. No amount of Congressional scrutiny is going to change that. If we intend on continuing to evolve our presence in space, and I would suggest that as a matter of national security we don’t really have a choice in that matter, we are going to have to understand that it is research and development. Research and development is by its very nature unpredictable.
Leaving that aside for a moment, I would like to point out that we have not changed the process that caused both accidents. As a matter of fact, budgetary concerns for every increasingly smaller amounts of funding have tended to sharpen and increase that pressure. In other words, we have not only not alleviated the problem, we have made it worse.
Currently, NASA is being redirected to concentrate on interplanetary exploration. Lower Earth Orbit space is being handed off to private industry. This includes satellite launch capabilities and Space Station access. Make no mistake about it, NASA is still tasked with funding the research and development necessary to accomplish this but the money is going to private industry. People seem to think a lot of private investors are ponying up the money for Space Ex, Orbital Sciences, and Boeing to handle these concerns but nothing could be further from the truth.
Developing launch vehicles and systems is still research and development. The only difference for private entities is that there is nothing to offset the schedule pressure. In other words, the competitive process wherein the winner takes all has led to even more schedule pressure. The prize is government funding. The loser gets to lose both their funding and their reputation. We have seen the results of this process, both at Wallops Island when the Antares rocket of Orbital Sciences blew up shortly after takeoff and at Cape Canaveral in June when a Space Ex Falcon exploded two minutes into its flight. We can add to that a Russian Progress 59 freighter that burned up in Earth’s atmosphere on May 7, 2015 to present a clear picture of just how hard space flight actually happens to be.
Private companies exist for one reason and one reason only; to make a profit. No other concern is even a close second. It is ludicrous to suppose that schedule pressure based upon budgetary concerns that have caused a government agency to make bad decisions will somehow be better handled by a private concern solely driven by profit. It is just not possible for a private company to react in any other way.
Having been intimately involved in this industry for thirty years now, I have seen a lot of NASA programs come and go. All of them were feasible. All of them were well thought out plans for getting to the next step, for continuing the process of astounding technological advancement that has been the hallmark of the US space program from its inception. All of them were killed by budgetary concerns.
Until we get a handle on how to fund research and development for long term goals I don’t see much possibility that things will change. Private space is not the answer now and it never will be. There is no profit in private space. There is a profit in the indirect and usually unknowable advancement that such technology produces but that is long term and unforeseeable.
The technological advancements that have come from NASA’s efforts are vast and quite astounding as to how they have affected the every-day life of every human on earth. I suspect this will continue for a long as NASA exists. It’s a shame that they are currently being limited by the narrowness of vision that doesn’t allow us to see the whole picture. We don’t seem to recognize the vast Forrest of opportunity that space exploration has produced because we are too concerned with what matchsticks cost.
NASA learned early that small mistakes and minor miscalculations lead to large disasters. Throughout the early years we learned at an accelerated pace that we must minimize the unknowns and maximize the testing to cover every possible variable. Vehicle designs are redundant for all critical failure possibilities. We simply can’t afford to lose a vehicle, more especially a vehicle with people on board because of one component failure especially when we understand that there are a vast number of components in each vehicle.
I was not working at NASA when the Challenger accident occurred but I was here when the Columbia accident occurred. One basic cultural problem led to both failures; schedule pressure overrode technical concerns. It really is that simple. NASA works off of an annually renewable budget that has to be approved by Congress. It is a special executive branch agency similar to the CIA in that the president appoints the director and largely controls its main directives. The head of the agency is approved by the Senate and the budget is controlled by Congress.
Both Shuttle disasters were caused by schedule pressure that was brought to bear based upon funding concerns. NASA’s funding is a political football that is regularly booted about when it comes time to pass a federal budget. At its funding peak during the Apollo buildup NASA received about 4% of the federal budget. In 1975 this fell to below 1% where it has remained since that time. In the early 2000’s it began falling again to the point where by 2012 it has fell below .5%. It has languished there since that time.
The schedule pressure that caused the accidents came from trying to meet projections that had been agreed to with Congress. NASA has learned by experience that delays and slips of projected schedules come at a dear expense. Congress regularly defunds programs that fall behind schedule. NASA reacts by doing the same thing on a smaller scale. When a large program falls behind projected schedule, small programs are defunded on a regular basis.
As the Columbia Accident Investigation Board (CAIB) report that came out after Columbia crashed points out, it is this schedule pressure that led to this accident and the Challenger accident before. Unfortunately, we seem to have taken this report and concentrated on the technical aspects of what caused the actual vehicle to crash without fully comprehending that the larger budgetary concerns are what led to the decision making process that crashed Columbia. In other words, it wasn’t a technical issue that caused the accident; but rather a whole series of decisions before and after the technical issue that were overwhelmingly driven by budgetary concerns at the top levels of NASA.
There is a smoking gun involved but it was loaded, primed, and fired by a budgetary weakness at the heart of NASA’s existence. Annually renewable budgets based upon projections of research and development are inherently inaccurate entities. No amount of Congressional scrutiny is going to change that. If we intend on continuing to evolve our presence in space, and I would suggest that as a matter of national security we don’t really have a choice in that matter, we are going to have to understand that it is research and development. Research and development is by its very nature unpredictable.
Leaving that aside for a moment, I would like to point out that we have not changed the process that caused both accidents. As a matter of fact, budgetary concerns for every increasingly smaller amounts of funding have tended to sharpen and increase that pressure. In other words, we have not only not alleviated the problem, we have made it worse.
Currently, NASA is being redirected to concentrate on interplanetary exploration. Lower Earth Orbit space is being handed off to private industry. This includes satellite launch capabilities and Space Station access. Make no mistake about it, NASA is still tasked with funding the research and development necessary to accomplish this but the money is going to private industry. People seem to think a lot of private investors are ponying up the money for Space Ex, Orbital Sciences, and Boeing to handle these concerns but nothing could be further from the truth.
Developing launch vehicles and systems is still research and development. The only difference for private entities is that there is nothing to offset the schedule pressure. In other words, the competitive process wherein the winner takes all has led to even more schedule pressure. The prize is government funding. The loser gets to lose both their funding and their reputation. We have seen the results of this process, both at Wallops Island when the Antares rocket of Orbital Sciences blew up shortly after takeoff and at Cape Canaveral in June when a Space Ex Falcon exploded two minutes into its flight. We can add to that a Russian Progress 59 freighter that burned up in Earth’s atmosphere on May 7, 2015 to present a clear picture of just how hard space flight actually happens to be.
Private companies exist for one reason and one reason only; to make a profit. No other concern is even a close second. It is ludicrous to suppose that schedule pressure based upon budgetary concerns that have caused a government agency to make bad decisions will somehow be better handled by a private concern solely driven by profit. It is just not possible for a private company to react in any other way.
Having been intimately involved in this industry for thirty years now, I have seen a lot of NASA programs come and go. All of them were feasible. All of them were well thought out plans for getting to the next step, for continuing the process of astounding technological advancement that has been the hallmark of the US space program from its inception. All of them were killed by budgetary concerns.
Until we get a handle on how to fund research and development for long term goals I don’t see much possibility that things will change. Private space is not the answer now and it never will be. There is no profit in private space. There is a profit in the indirect and usually unknowable advancement that such technology produces but that is long term and unforeseeable.
The technological advancements that have come from NASA’s efforts are vast and quite astounding as to how they have affected the every-day life of every human on earth. I suspect this will continue for a long as NASA exists. It’s a shame that they are currently being limited by the narrowness of vision that doesn’t allow us to see the whole picture. We don’t seem to recognize the vast Forrest of opportunity that space exploration has produced because we are too concerned with what matchsticks cost.
Thursday, September 1, 2016
Red Devils and Munchkins
Years ago I worked with a crane operator who had his own pronunciation system. JN was an excellent crane operator and a smart guy besides. He ran several successful little side businesses at the same time he worked in our technician crew. He was the kind of guy who would give you the shirt off his back if you needed help but would also squeeze the last nickel out of every business transaction. I liked him immediately when I met him.
JN used some of the strangest words I have ever heard anyone use. It wasn’t that he couldn’t enunciate he just enunciated differently. Every one of the words he struggled with sounded like the correct word but they were always just a little bit off. A computer was a suputer in JN’s language. He drove an old El Camino truck that had been pristinely restored. It was not an El Camino but an El Torino to JN. There was a long list of things that JN just didn’t seem to want to take the time to pronounce correctly. I could never figure out if he just wasn’t interested in pronunciation or if he just favored his own way of doing it over that used by everyone else.
He soon was a little famous in our shop for his use of non-words. People would ask him to tell stories about things just to catch the string of alternate pronunciations that always spewed force when he did. Sometimes people would correct him but he paid it no mind at all when they did. One of our engineers carefully corrected him on his usage of the term computer during a scheduling meeting.
JN: “We couldn’t get the funtroller for the suputer working on that new pump engine so we ran it automanually.”
Engineer: “Uh…. you mean the controller?”
JN: “Yes…. Ricky said there was something wrong with the communication manual or funtroller so we ran it automanually.”
Engineer: “The communication manual?”
JN: “Yes…. the manual that talks to the suputer.”
Engineer: “You mean computer?”
JN: “Yes… the supputer has to talk to the communication manual to run by itself so we ran it in automanual.”
Engineer: “You mean communication module?”
JN: “I already told you that.”
Engineer: “Did you run in automatic or manual mode?”
JN: “We ran it by hand, you know… the old fashioned way.”
You could easily get on a redundant regressive loop of growing confusion talking with JN unless you understood his language. We took to calling it “JN speak” and the best thing to do was learn to make associations between what he said and what he actually meant. Once you got used to it, it wasn’t too bad but initially it could throw a monkey wrench into communication that was pretty frustrating; especially if you were in a hurry.
As careless as JN was in his use of language, he was the polar opposite in his fastidiousness in almost every other aspect of his life. He worked in one of the pumphouses that supplied cooling water to the test stands at NASA when he wasn’t operating cranes. Since most of the parts of the big locomotive diesels required careful crane handling control in putting them in place during engine rebuilds he was invaluable to the head mechanic. He always insisted on JN being the operator when he was rebuilding engines as he JN was amazingly deft in handling and moving things with a crane.
When the pumphouse was running supporting tests, JN was an operator who ran the control system that ramped the engines and operating the valve systems in the pumphouse. He took this same level of exacting fastidiousness to this pursuit as well. He was an excellent operator who knew the system backwards and forwards and was always one step ahead in his mind when following operating procedures.
On days where the test stands experienced delays, the pumphouse would go into standby mode with engines idling; simply maintaining water pressure on the coolant and fire control systems until whatever was wrong on the test stand could be worked out. Some of these delays were pretty long and boring. On those days, JN always had some sort of home project in his car to work on. He would bring silverware in to polish or kitchen knives to sharpen; something along those lines while he waited. During one such delay I was working on repairing some of the large 54” water valve controllers on the system while we were in delay so I was in constant communication with the pumphouse. As we finished our repairs and had JN cycle test the valves to check limit switch positions, the test stand came online to tell us we were 20 minutes from test.
We got in our truck and drove back to the pumphouse to wait out the test. It was a short cycle test which was supposed to run for 3 minutes; after which we could resume our system repairs. When we got back to the pumphouse control room I noticed JN was busily polishing some metal pieces that he had wrapped in a shop rag. Curious, I looked over his shoulder to see what looked like a brass door hinge in his hands and several more still wrapped in the shop rag.
Me…. “Is that a door hinge?”
JN…. “Yes” he said as nonchalant as ever.I noticed he also had a can of Brasso and was steadily making the hinge shine to a high polish.
Me… “Why are you polishing door hinges?”
JN…. “It’s just that time. I polish all of them once a year,” as if every sane person pulled their door hinges off to polish them annually.
Me….”uh…. ok.” What could I say? I am not exaggerating when I say that if I live to be a hundred I would likely never have thought of such a thing. I looked over at Clinton who also worked in the pumphouse and he was just smiling broadly as he shrugged his shoulders. That was JN to a tee. Fastidious and at the same time incomprehensible.
Some months later as we were all eating lunch one day JN launched into an angry explanation that something was tearing up his new manicured lawn. JN had just paid a lot of money to a landscaping company to redo his lawn to his exacting standards. JN hated to part with money to begin with but money wasted was a cardinal sin in his eyes. He was quite incensed about the whole thing, grumbling about how much money he spent and how it was all thrown away.
JN… “I may as well burn a wet dog.”
Me…. “What??”
JN… “I spent enough money on that yard to burn a wet dog and all I got to show for it is a bunch of panholes.”
Me…. “Panholes?”
JN… “Critter holes.”
Me…. “Is something digging in your yard, digging potholes?”
JN… “Yes. Panholes; I’m going to get my rifle and shoot the little bastards.”
Me… “What are you going to shoot?”
JN… “The little bastards digging holes; Munchkins.”
Me…. thinking…. “Uh…. you mean chipmunks?”
JN…. “Yes… the little bastards are tearing up my yard and I am going to start shooting them.”
I knew JN lived in a very nice area of Huntsville but it was also very crowded with houses and completely in the middle of town. Shooting a rifle inside the city limits was not a good idea.
Me… “JN…. You can’t be shooting a rifle in your front yard. The cops will come arrest you.”
JN…. “Well then…. THEY can come shoot the little bastards but I ain’t going to let them tear my whole yard up after I spent a fortune getting it that way I want it.”
Me…. “I don’t think they will do that either. But you need to talk to them before you get a rifle out in the front yard and go to blasting away at Chipmunks.”
JN drew a puff on his pipe and seemed to mull that over for a few minutes.
JN… “Aye god, you might be right. I think I’ll call the sheriff’s department and tell them.”
JN walked over to the desk in the shop and got out the phone book to call the Sheriff’s department. He was still mad but at least he was not likely to get arrested by calling them first. Besides, I thought they might have a suggestion of someone who could get rid of the chipmunks as well. The conversation that followed was one that I could only hear one side of. I can well imagine what went on at the other end of it but could only judge it by how loud the tone got from the sound that escaped the earpiece.
JN…. “Hello… I have a problem and need to speak to someone about it.”
After a brief pause…
JN…. “Well… I just paid a lot of money to get my yard redone and now some munckins are digging it up. I want to just get my rifle and shoot the little devils but my friend tells me that I can’t do that in this city.”
Another pause….
JN….”Yes maam….. they are digging holes in my yard.”
Another pause…
JN…. “I don’t know why; it’s just the kind of thing munchkins like to do I guess.”
Another pause…
JN…. “You know MUNCHKINS,” as if saying it louder should clear up the misconception. “Little red devils. I’m going to get my rifle and light their little butts up the next time I see one in my yard.”
Another pause followed by a rising tone coming from the other end of the phone.
JN… “Never mind where I live. I would shoot them for tearing up your yard too. I hate the little devils.”
By this time I was trying to catch his attention…
Me…. “JN…. Tell them chipmunks! Say CHIPMUNK!”
JN… “That’s what I told her, MUNCHKINS.”
More rising tone on the other end of the phone….
JN… “I’ll shoot the little devils if I want. You can come bury their little butts if I catch any more of them in my yard.” He was yelling into the phone.
Me…. “CHIPMUNKS, CHIPMUNKS “
I was trying to yell loud enough so that whoever was on the other end of the phone could hear so they wouldn’t think a lot of local neighborhood children were getting ready to be assassinated by some crazed lawn care fanatic.
JN… “OK… then YOU can come kill them, but they are NOT going to tear up my lawnscaping anymore; I can gay-run-tee you that.”
Before anyone could say anything else, JN hung up the phone. It’s probably a good thing they didn’t have caller ID in those days. I tried to explain to JN the difference between chipmunks and the vision most people get in their head when you say “munchkin” but he had no interest in my explanation. The Sheriff’s department probably gets their fair share of strange calls to begin with but I could tell from the rising tone escaping the earpiece that someone got a good story to tell later on that morning; probably in horror.
JN used some of the strangest words I have ever heard anyone use. It wasn’t that he couldn’t enunciate he just enunciated differently. Every one of the words he struggled with sounded like the correct word but they were always just a little bit off. A computer was a suputer in JN’s language. He drove an old El Camino truck that had been pristinely restored. It was not an El Camino but an El Torino to JN. There was a long list of things that JN just didn’t seem to want to take the time to pronounce correctly. I could never figure out if he just wasn’t interested in pronunciation or if he just favored his own way of doing it over that used by everyone else.
He soon was a little famous in our shop for his use of non-words. People would ask him to tell stories about things just to catch the string of alternate pronunciations that always spewed force when he did. Sometimes people would correct him but he paid it no mind at all when they did. One of our engineers carefully corrected him on his usage of the term computer during a scheduling meeting.
JN: “We couldn’t get the funtroller for the suputer working on that new pump engine so we ran it automanually.”
Engineer: “Uh…. you mean the controller?”
JN: “Yes…. Ricky said there was something wrong with the communication manual or funtroller so we ran it automanually.”
Engineer: “The communication manual?”
JN: “Yes…. the manual that talks to the suputer.”
Engineer: “You mean computer?”
JN: “Yes… the supputer has to talk to the communication manual to run by itself so we ran it in automanual.”
Engineer: “You mean communication module?”
JN: “I already told you that.”
Engineer: “Did you run in automatic or manual mode?”
JN: “We ran it by hand, you know… the old fashioned way.”
You could easily get on a redundant regressive loop of growing confusion talking with JN unless you understood his language. We took to calling it “JN speak” and the best thing to do was learn to make associations between what he said and what he actually meant. Once you got used to it, it wasn’t too bad but initially it could throw a monkey wrench into communication that was pretty frustrating; especially if you were in a hurry.
As careless as JN was in his use of language, he was the polar opposite in his fastidiousness in almost every other aspect of his life. He worked in one of the pumphouses that supplied cooling water to the test stands at NASA when he wasn’t operating cranes. Since most of the parts of the big locomotive diesels required careful crane handling control in putting them in place during engine rebuilds he was invaluable to the head mechanic. He always insisted on JN being the operator when he was rebuilding engines as he JN was amazingly deft in handling and moving things with a crane.
When the pumphouse was running supporting tests, JN was an operator who ran the control system that ramped the engines and operating the valve systems in the pumphouse. He took this same level of exacting fastidiousness to this pursuit as well. He was an excellent operator who knew the system backwards and forwards and was always one step ahead in his mind when following operating procedures.
On days where the test stands experienced delays, the pumphouse would go into standby mode with engines idling; simply maintaining water pressure on the coolant and fire control systems until whatever was wrong on the test stand could be worked out. Some of these delays were pretty long and boring. On those days, JN always had some sort of home project in his car to work on. He would bring silverware in to polish or kitchen knives to sharpen; something along those lines while he waited. During one such delay I was working on repairing some of the large 54” water valve controllers on the system while we were in delay so I was in constant communication with the pumphouse. As we finished our repairs and had JN cycle test the valves to check limit switch positions, the test stand came online to tell us we were 20 minutes from test.
We got in our truck and drove back to the pumphouse to wait out the test. It was a short cycle test which was supposed to run for 3 minutes; after which we could resume our system repairs. When we got back to the pumphouse control room I noticed JN was busily polishing some metal pieces that he had wrapped in a shop rag. Curious, I looked over his shoulder to see what looked like a brass door hinge in his hands and several more still wrapped in the shop rag.
Me…. “Is that a door hinge?”
JN…. “Yes” he said as nonchalant as ever.I noticed he also had a can of Brasso and was steadily making the hinge shine to a high polish.
Me… “Why are you polishing door hinges?”
JN…. “It’s just that time. I polish all of them once a year,” as if every sane person pulled their door hinges off to polish them annually.
Me….”uh…. ok.” What could I say? I am not exaggerating when I say that if I live to be a hundred I would likely never have thought of such a thing. I looked over at Clinton who also worked in the pumphouse and he was just smiling broadly as he shrugged his shoulders. That was JN to a tee. Fastidious and at the same time incomprehensible.
Some months later as we were all eating lunch one day JN launched into an angry explanation that something was tearing up his new manicured lawn. JN had just paid a lot of money to a landscaping company to redo his lawn to his exacting standards. JN hated to part with money to begin with but money wasted was a cardinal sin in his eyes. He was quite incensed about the whole thing, grumbling about how much money he spent and how it was all thrown away.
JN… “I may as well burn a wet dog.”
Me…. “What??”
JN… “I spent enough money on that yard to burn a wet dog and all I got to show for it is a bunch of panholes.”
Me…. “Panholes?”
JN… “Critter holes.”
Me…. “Is something digging in your yard, digging potholes?”
JN… “Yes. Panholes; I’m going to get my rifle and shoot the little bastards.”
Me… “What are you going to shoot?”
JN… “The little bastards digging holes; Munchkins.”
Me…. thinking…. “Uh…. you mean chipmunks?”
JN…. “Yes… the little bastards are tearing up my yard and I am going to start shooting them.”
I knew JN lived in a very nice area of Huntsville but it was also very crowded with houses and completely in the middle of town. Shooting a rifle inside the city limits was not a good idea.
Me… “JN…. You can’t be shooting a rifle in your front yard. The cops will come arrest you.”
JN…. “Well then…. THEY can come shoot the little bastards but I ain’t going to let them tear my whole yard up after I spent a fortune getting it that way I want it.”
Me…. “I don’t think they will do that either. But you need to talk to them before you get a rifle out in the front yard and go to blasting away at Chipmunks.”
JN drew a puff on his pipe and seemed to mull that over for a few minutes.
JN… “Aye god, you might be right. I think I’ll call the sheriff’s department and tell them.”
JN walked over to the desk in the shop and got out the phone book to call the Sheriff’s department. He was still mad but at least he was not likely to get arrested by calling them first. Besides, I thought they might have a suggestion of someone who could get rid of the chipmunks as well. The conversation that followed was one that I could only hear one side of. I can well imagine what went on at the other end of it but could only judge it by how loud the tone got from the sound that escaped the earpiece.
JN…. “Hello… I have a problem and need to speak to someone about it.”
After a brief pause…
JN…. “Well… I just paid a lot of money to get my yard redone and now some munckins are digging it up. I want to just get my rifle and shoot the little devils but my friend tells me that I can’t do that in this city.”
Another pause….
JN….”Yes maam….. they are digging holes in my yard.”
Another pause…
JN…. “I don’t know why; it’s just the kind of thing munchkins like to do I guess.”
Another pause…
JN…. “You know MUNCHKINS,” as if saying it louder should clear up the misconception. “Little red devils. I’m going to get my rifle and light their little butts up the next time I see one in my yard.”
Another pause followed by a rising tone coming from the other end of the phone.
JN… “Never mind where I live. I would shoot them for tearing up your yard too. I hate the little devils.”
By this time I was trying to catch his attention…
Me…. “JN…. Tell them chipmunks! Say CHIPMUNK!”
JN… “That’s what I told her, MUNCHKINS.”
More rising tone on the other end of the phone….
JN… “I’ll shoot the little devils if I want. You can come bury their little butts if I catch any more of them in my yard.” He was yelling into the phone.
Me…. “CHIPMUNKS, CHIPMUNKS “
I was trying to yell loud enough so that whoever was on the other end of the phone could hear so they wouldn’t think a lot of local neighborhood children were getting ready to be assassinated by some crazed lawn care fanatic.
JN… “OK… then YOU can come kill them, but they are NOT going to tear up my lawnscaping anymore; I can gay-run-tee you that.”
Before anyone could say anything else, JN hung up the phone. It’s probably a good thing they didn’t have caller ID in those days. I tried to explain to JN the difference between chipmunks and the vision most people get in their head when you say “munchkin” but he had no interest in my explanation. The Sheriff’s department probably gets their fair share of strange calls to begin with but I could tell from the rising tone escaping the earpiece that someone got a good story to tell later on that morning; probably in horror.
Subscribe to:
Posts (Atom)