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SpaceX Launch Update
FWIW Got this from the SpaceX email list:
Launch Date The new launch date is approximately December 20, depending on when the Missile Defense Agency testing is complete. As soon as we have a firm time, it will be posted on the SpaceX website. Liquid Oxygen Regarding liquid oxygen (LOX) supplies, we expect to have enough on hand this time to fill the rocket four or five times over. This should account for almost any issue with a particular storage tank as well as an extended hold on the pad. There is an engineering term known as a s*load. I have asked that we have at least two s*loads on hand in case one s*load is not enough. We chartered a C-17 to fly two of our empty high quality LOX containers to Hawaii, sourced another high quality LOX container on Hawaii and put all three on the barge to Kwajalein. In addition, our LOX plant on Kwajalein has been repaired and is producing LOX on island again. Some might be wondering why we were so dumb as to run out of LOX on a remote tropical island on the last launch attempt. Believe me, we tried hard to avoid it, but several issues conspired to create the problem: * The additional month of Merlin testing resulted in additional LOX boil-off on island. Even though it is stored in vacuum jacketed containers, LOX at -300F degrees does not like being on a tropical island at 85F. *The SpaceX LOX plant on island broke down a few weeks prior to launch, which meant we could not top up. *We ordered replacement LOX from Hawaii, but the container quality was poor, so only 20% of what we ordered actually arrived. *Ground winds were unusually high on launch day, which amplifies the boil-off rate significantly, since the Falcon's first stage LOX tank is uninsulated. *All of the above would not have mattered if our final storage tank did not have a small, manual vent valve incorrectly in the open position. Somewhat agonizingly, we were only a few percent away from being full. We just needed a little sip from the last tank. *After a while, we were able to close the vent and fill the vehicle's LOX tanks. However, we use LOX to chill our onboard helium and the absence of ground LOX to do so resulted in the helium heating up and venting back to storage. In the end, we did not have enough LOX to stay filled on the rocket and chill & pressurize the helium. Engine Computer The engine computer reboot anomaly was definitively traced to a ground power problem. Importantly, this would have had no effect on flight, since we switch to vehicle power before the autosequence begins. The reason it cropped up at Kwajalein was that the higher load on the longer umbilical (three times longer than in prior tests) coupled with high temperatures in Kwajalein resulted in increased resistance in the ground umbilical. This was just enough to lower the voltage below minimums and cause an engine computer reset when drawing maximum power. The same max power test was repeated on internal vehicle batteries with no problem at all. This problem has been solved by slightly increasing voltage on the ground umbilical. --Elon-- Well we know the whole story, do we cut them some slack for this? Just my $0.02 Space Cadet |
#2
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SpaceX Launch Update
Space Cadet wrote: FWIW Got this from the SpaceX email list: Launch Date The new launch date is approximately December 20, depending on when the Missile Defense Agency testing is complete. As soon as we have a firm time, it will be posted on the SpaceX website. This sounds familiar. Will launch as soon as the Pentagon has managed to launch something else. Lots of food for the conspiracy theorists - Spacex will need a sea launch soon. |
#3
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SpaceX Launch Update
"Space Cadet" wrote:
Some might be wondering why we were so dumb as to run out of LOX on a remote tropical island on the last launch attempt. Believe me, we tried hard to avoid it, but several issues conspired to create the problem: * The additional month of Merlin testing resulted in additional LOX boil-off on island. Huh? What additional testing was needed? D. -- Touch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
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SpaceX Launch Update
Derek Lyons wrote: "Space Cadet" wrote: Some might be wondering why we were so dumb as to run out of LOX on a remote tropical island on the last launch attempt. Believe me, we tried hard to avoid it, but several issues conspired to create the problem: * The additional month of Merlin testing resulted in additional LOX boil-off on island. Huh? What additional testing was needed? SpaceX suffered a Merlin engine failure on its Texas test stand back on September 7, 2005. The additional testing was presumably with another engine sent to Texas. SpaceX delayed the Kwaj launch (originally planned for late September) while this testing was underway, which caused more of the LOX stored at Kwaj/Omelek to boil off than would have if they had made the original launch date. A tangled web, space launch is. - Ed Kyle |
#6
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SpaceX Launch Update
Ed Kyle wrote: SpaceX suffered a Merlin engine failure on its Texas test stand back on September 7, 2005. The additional testing was presumably with another engine sent to Texas. SpaceX delayed the Kwaj launch (originally planned for late September) while this testing was underway, which caused more of the LOX stored at Kwaj/Omelek to boil off than would have if they had made the original launch date. A tangled web, space launch is. - Ed Kyle After many launch delays, the black and white Columbia came to be known as the "Penguin" (a flightless bird). Maybe it's time to change the "Falcon" to........ (pick one): -Ostrich -Rhea -Cassowary -Emu -Kiwi -Kakapo -Takahe -Tinamou -Moa -Dodo ;-) Rusty |
#7
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SpaceX Launch Update
"Ed Kyle" wrote:
Derek Lyons wrote: "Space Cadet" wrote: Some might be wondering why we were so dumb as to run out of LOX on a remote tropical island on the last launch attempt. Believe me, we tried hard to avoid it, but several issues conspired to create the problem: * The additional month of Merlin testing resulted in additional LOX boil-off on island. Huh? What additional testing was needed? SpaceX suffered a Merlin engine failure on its Texas test stand back on September 7, 2005. The additional testing was presumably with another engine sent to Texas. SpaceX delayed the Kwaj launch (originally planned for late September) while this testing was underway, which caused more of the LOX stored at Kwaj/Omelek to boil off than would have if they had made the original launch date. A tangled web, space launch is. OK, that makes sense. I parsed that (incorrectly) as 'an additional month of testing [at the launch site]'. D. -- Touch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
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SpaceX Launch Update
"Ed Kyle" wrote in message
oups.com... SpaceX suffered a Merlin engine failure on its Texas test stand back on September 7, 2005. The additional testing was presumably with another engine sent to Texas. SpaceX delayed the Kwaj launch (originally planned for late September) while this testing was underway, which caused more of the LOX stored at Kwaj/Omelek to boil off than would have if they had made the original launch date. Personally I am not so concerned by a few delays, a few failures even, as long as they make fast, cheap and steady progress towards success. One of my current concerns is that SpaceX will become so risk adverse that they will attempt success at any price, becoming just another expensive launch system. Some of their current failure avoidance measures do seem to be overkill. I think one of the critical lessons from this development has been that such a low cost launch system must be designed to avoid third party launch schedule limitations. A serious development needs to be able to attempt a launch near every day, SpaceX are not managing once a month. They are now throwing money at the problem to try and compensate - not good. Pete. |
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SpaceX Launch Update
Pete Lynn wrote:
I think one of the critical lessons from this development has been that such a low cost launch system must be designed to avoid third party launch schedule limitations. A serious development needs to be able to attempt a launch near every day, SpaceX are not managing once a month. They are now throwing money at the problem to try and compensate - not good. It appears more and more likely that commercial launch needs to decouple from DoD launch sites to become practical. But SpaceX is, of course, doing most of its launches for DoD, so the delays are self-inflicted by the customer in that sense. I wonder who pays for the cost of range delays? - Ed Kyle |
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