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#11
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Unplanned engine-out resiliance test for CRS-1 Falcon 9?
On Monday, October 8, 2012 6:11:08 PM UTC-4, Rick Jones wrote:
It would seem that the most recent Falcon 9 launch included an unplanned test of its engine-out capability: http://www.theregister.co.uk/2012/10...alco_flameout/ rick jones -- the road to hell is paved with business decisions... these opinions are mine, all mine; HP might not want them anyway... feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH... That's a nice explanation. Now as far as that secondary payload? Is it totally useless? If so, would there be any insurance coverage? |
#12
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Unplanned engine-out resiliance test for CRS-1 Falcon 9?
On Oct 10, 7:28*am, Dean wrote:
On Monday, October 8, 2012 6:11:08 PM UTC-4, Rick Jones wrote: It would seem that the most recent Falcon 9 launch included an unplanned test of its engine-out capability: http://www.theregister.co.uk/2012/10...alco_flameout/ rick jones -- the road to hell is paved with business decisions... these opinions are mine, all mine; HP might not want them anyway... feel free to post, OR email to rick.jones2 in hp.com *but NOT BOTH... That's a nice explanation. *Now as far as that secondary payload? *Is it totally useless? *If so, would there be any insurance coverage? For a hefty fee and/or substantial deductible, anything can be insured or bet upon. Possibly they bought a 50% coverage policy for a million bucks. |
#13
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Unplanned engine-out resiliance test for CRS-1 Falcon 9?
On 10/10/2012 8:48 AM, Jeff Findley wrote:
The second stage only has one engine, so burning longer left it with less fuel than a nominal mission. This meant that there wasn't enough fuel for the next burn. This burn would have placed the secondary payload into its final orbit. This was at least a partial failure for the secondary payload any way you look at it. Not exactly the way I read it over on Arocket. IIRC I think the issue was not that there was not enough fuel to do the final orbit burn for the secondary payload but that the amount remaining after Dragon insertion (because of the extended 2nd stage burn due to loss of 1 F9 engine) was below the minimums needed to assure success. In other words it was below the 'reserve' allocated to do that to guarantee no problems with orbital position relative to ISS. After reading that I presumed that 'reserve' was an engineering estimate that would normally be conservative and thus beyond what was actually required. Admittedly a guess on my part. Unfortunately, because of the ISS constraint, SpaceX wasn't allowed to perform any additional burn using the fuel remaining in the second stage. So, the backup plan was initiated which released the secondary payload into the parking orbit, which is a far cry from its intended orbit. If it weren't for the ISS constraint, SpaceX surely would have done the second burn (likely to fuel depletion) in order to place the secondary payload into as favorable of an orbit as they could. But they couldn't, which is a shame for the secondary payload. I don't think to depletion would have been necessary, but likely would have left the 2nd stage with less than what was estimated to be safe (for ISS). The bottom line is that this was a successful launch of the primary payload (Dragon), but a nearly complete failed launch for the secondary payload. Sucks to be a secondary payload when "stuff happens". Yup. However, it is also an opportunity. As a paying secondary customer, maybe in the future I can get a break on my bill because of this higher risk than say, I might pay to be a secondary payload on a mission of less risk, like a GEO sat insertion primary payload which has no risk of collision with ISS or any other manned object? Jeff Dave **Ebeneezer** Scrooge |
#14
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Unplanned engine-out resiliance test for CRS-1 Falcon 9?
On Oct 9, 6:27*pm, Rick Jones wrote:
... -- A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail? Works well enough on Jeopardy. Bob Clark |
#15
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Unplanned engine-out resiliance test for CRS-1 Falcon 9?
"Robert Clark" wrote in message
... On Oct 9, 6:27 pm, Rick Jones wrote: ... -- A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail? Works well enough on Jeopardy. Great. And when I can win thousands of dollars posting to Usenet, please let me know. Bob Clark -- Greg D. Moore http://greenmountainsoftware.wordpress.com/ CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net |
#16
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Unplanned engine-out resiliance test for CRS-1 Falcon 9?
In article , nospam@
127.0.0.1 says... On 10/10/2012 8:48 AM, Jeff Findley wrote: The second stage only has one engine, so burning longer left it with less fuel than a nominal mission. This meant that there wasn't enough fuel for the next burn. This burn would have placed the secondary payload into its final orbit. This was at least a partial failure for the secondary payload any way you look at it. Not exactly the way I read it over on Arocket. IIRC I think the issue was not that there was not enough fuel to do the final orbit burn for the secondary payload but that the amount remaining after Dragon insertion (because of the extended 2nd stage burn due to loss of 1 F9 engine) was below the minimums needed to assure success. In other words it was below the 'reserve' allocated to do that to guarantee no problems with orbital position relative to ISS. After reading that I presumed that 'reserve' was an engineering estimate that would normally be conservative and thus beyond what was actually required. Admittedly a guess on my part. Unfortunately, because of the ISS constraint, SpaceX wasn't allowed to perform any additional burn using the fuel remaining in the second stage. So, the backup plan was initiated which released the secondary payload into the parking orbit, which is a far cry from its intended orbit. If it weren't for the ISS constraint, SpaceX surely would have done the second burn (likely to fuel depletion) in order to place the secondary payload into as favorable of an orbit as they could. But they couldn't, which is a shame for the secondary payload. I don't think to depletion would have been necessary, but likely would have left the 2nd stage with less than what was estimated to be safe (for ISS). From newspacewatch.com: NASA had required that a restart of the upper stage only occur if there was a very high probability (over 99%) of fully completing the second burn. While there was sufficient fuel on board to do so, the liquid oxygen on board was only enough to achieve a roughly 95% likelihood of completing the second burn, so Falcon 9 did not attempt a restart. From this, it seems that there was a 95% chance of the burn completing. The remaining 5% chance was the case that the LOX would have burned to depletion. The bottom line is that this was a successful launch of the primary payload (Dragon), but a nearly complete failed launch for the secondary payload. Sucks to be a secondary payload when "stuff happens". Yup. However, it is also an opportunity. As a paying secondary customer, maybe in the future I can get a break on my bill because of this higher risk than say, I might pay to be a secondary payload on a mission of less risk, like a GEO sat insertion primary payload which has no risk of collision with ISS or any other manned object? It would be interesting to find out what the cost for this flight was since the secondary payloads are taking a greater risk than the primary, especially when the primary involves NASA and ISS. Jeff -- "the perennial claim that hypersonic airbreathing propulsion would magically make space launch cheaper is nonsense -- LOX is much cheaper than advanced airbreathing engines, and so are the tanks to put it in and the extra thrust to carry it." - Henry Spencer |
#17
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Unplanned engine-out resiliance test for CRS-1 Falcon 9?
Jeff Findley explained :
[David Spain, although Jeff's newsreader may have been confused about that] Yup. However, it is also an opportunity. As a paying secondary customer, maybe in the future I can get a break on my bill because of this higher risk than say, I might pay to be a secondary payload on a mission of less risk, like a GEO sat insertion primary payload which has no risk of collision with ISS or any other manned object? It would be interesting to find out what the cost for this flight was since the secondary payloads are taking a greater risk than the primary, especially when the primary involves NASA and ISS. Quote from NBCNews.com: quote Satellite messaging service provider Orbcomm on Oct. 11 said its prototype second-generation satellite, launched Oct. 7 into a bad orbit by a Space Exploration Technologies Corp. (SpaceX) Falcon 9 rocket, had fallen out of orbit but had provided enough data to proceed with the launch of the full constellation starting next year. /quote url=http://www.msnbc.msn.com/id/49403078/ns/technology_and_science-space/#.UHzor8XA-So You may have seen the news at other sites, as well. /dps -- Who, me? And what lacuna? |
#18
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Should SpaceX use larger but fewer engines for reliability on the Falcon 9?
Jeff Findley wrote:
In article , says... I find it mildly amusing that you think a "large fireball" is not nearly as hazardous as an "explosion". Because it's not as hazardous, especially when you have a launch escape system in place to get you away from the fireball. As a check, since I have peanut-gallery difficulty with fireball vs explosion Was it a large fireball that enveloped (?) Challenger? rick jones trimming previous and now extraneous text, done well at least, is a good thing... -- oxymoron n, commuter in a gas-guzzling luxury SUV with an American flag these opinions are mine, all mine; HP might not want them anyway... feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH... |
#20
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Should SpaceX use larger but fewer engines for reliability on the Falcon 9?
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