snipWe're still thinking of "how to reduce max-Q to get around the problem", whilst Danny now tells us that max-Q is a relatively small part of the problem, thus why Jupiter is also affected.cheers, Martin
The dates which we submitted to Aerospace Corporation were:Jupiter-130 IOC -- March 2014Jupiter-241 IOC -- 2018We've seen some of the results already and without providing specific details, BOTH of those dates have been improved upon to the tune of at least 1 whole year and 2 years respectively -- which we aren't surprised about given that we packed all our schedules with plenty of surplus margins.
Quote from: kraisee on 07/29/2009 04:40 amThe dates which we submitted to Aerospace Corporation were:Jupiter-130 IOC -- March 2014Jupiter-241 IOC -- 2018(snip)I thought the committee stated or implied in one of the recent meetings that none of the options could reduce the gap before 2016 or something like that. Why would they say that if DIRECT can be ready for LEO in 2013? Can we conclude that the committee believes that Orion is the long pole?
The dates which we submitted to Aerospace Corporation were:Jupiter-130 IOC -- March 2014Jupiter-241 IOC -- 2018(snip)
Quote from: clongton on 07/30/2009 04:44 pmThere is an extremely serious safety hazard for the NSC abort mode which is under investigation. Remember that the abort motors are less than 10 feet away from the LOX tank on the ET. Remember also that the LOX tank walls are very thin and very pressure sensitive. The safety issue is that at the very instant of ignition of the abort motor, the ignition *shock wave* will disintigrate the LOX tank before the explosive bolts that will free Orion from the SM have even completed their de-couple.That envelops Orion in a cloud of LOX and tank debris with abort motors burning before she even leaves the stack. It's being looked at. No official results yet.The HLV Crew Abort Assessment (preliminary report - headed by Doug Whitehead) does not mention that. Actually they mention that there are no recontact issue with the ET (page 32). Of course the assessment mentions there is a lot more work to do including "more detailed work on thermal and pressure effects in connection with plume interactions on ET". I however didn't see much on the issue of "shock interactions" other than that in the assessment.
There is an extremely serious safety hazard for the NSC abort mode which is under investigation. Remember that the abort motors are less than 10 feet away from the LOX tank on the ET. Remember also that the LOX tank walls are very thin and very pressure sensitive. The safety issue is that at the very instant of ignition of the abort motor, the ignition *shock wave* will disintigrate the LOX tank before the explosive bolts that will free Orion from the SM have even completed their de-couple.That envelops Orion in a cloud of LOX and tank debris with abort motors burning before she even leaves the stack. It's being looked at. No official results yet.
Quote from: clongton on 07/30/2009 04:44 pmsnipThere is an extremely serious safety hazard for the NSC abort mode which is under investigation. Remember that the abort motors are less than 10 feet away from the LOX tank on the ET. Remember also that the LOX tank walls are very thin and very pressure sensitive. The safety issue is that at the very instant of ignition of the abort motor, the ignition *shock wave* will disintigrate the LOX tank before the explosive bolts that will free Orion from the SM have even completed their de-couple.That envelops Orion in a cloud of LOX and tank debris with abort motors burning before she even leaves the stack. It's being looked at. No official results yet.Thank goodness. Plume impingement is a very real threat to the ET. Protecting the CM for Apollo was a lot of work.Danny Deger
snipThere is an extremely serious safety hazard for the NSC abort mode which is under investigation. Remember that the abort motors are less than 10 feet away from the LOX tank on the ET. Remember also that the LOX tank walls are very thin and very pressure sensitive. The safety issue is that at the very instant of ignition of the abort motor, the ignition *shock wave* will disintigrate the LOX tank before the explosive bolts that will free Orion from the SM have even completed their de-couple.That envelops Orion in a cloud of LOX and tank debris with abort motors burning before she even leaves the stack. It's being looked at. No official results yet.
Ross,I have probably missed the announcment of your get together tomorrow night. What time and where is it?Sadly, my software test will keep me from gonig to the committee session.Mike
l our schedules with plenty of surplus margins.Can we conclude that the committee believes that Orion is the long pole?
A far as I know it has the same thrust performance as the LAS. Danny Deger
Is plume impingement an issue for DIRECT as well?
Quote from: ar-phanad link=topic=17295.msg450174#msg450174Is plume impingement an issue for DIRECT as well?Jesse, it exists on Jupiter, just like on Shuttle, but the design has been done in order to explicity work in that environment.So, plume impingement still exists, but it is not a 'problem' on this vehicle.Ross
That is an important sales pitch...which was not used in any of the presentations.
Conversely, I see your point - throttling-down the SSME's (through to max-Q, not SRB burnout) seems to me like it should reduce max-Q.But Danny's later post has covered this:-Quote from: Danny Dot on 07/30/2009 02:40 am400 psf is better than 1200 psf, but even that low dynamic pressure does not solve the problem.I think the confusion here is this started out as "an Ares I problem, because of the very high max-Q pressures".We're still thinking of "how to reduce max-Q to get around the problem", whilst Danny now tells us that max-Q is a relatively small part of the problem, thus why Jupiter is also affected.cheers, Martin
400 psf is better than 1200 psf, but even that low dynamic pressure does not solve the problem.
Quote from: MP99 on 07/30/2009 07:41 amConversely, I see your point - throttling-down the SSME's (through to max-Q, not SRB burnout) seems to me like it should reduce max-Q.But Danny's later post has covered this:-Quote from: Danny Dot on 07/30/2009 02:40 am400 psf is better than 1200 psf, but even that low dynamic pressure does not solve the problem.I think the confusion here is this started out as "an Ares I problem, because of the very high max-Q pressures".We're still thinking of "how to reduce max-Q to get around the problem", whilst Danny now tells us that max-Q is a relatively small part of the problem, thus why Jupiter is also affected.cheers, MartinAh okay...Wow, even 400 psf is high. Well, let's put it this way: if it's bad for Direct, it's bad for EVERYONE ELSE.I'll play devil's advocate for once and say: NASA can (and must) solve this one
Quote from: kraisee on 07/29/2009 04:40 amThe dates which we submitted to Aerospace Corporation were:Jupiter-130 IOC -- March 2014Jupiter-241 IOC -- 2018We've seen some of the results already and without providing specific details, BOTH of those dates have been improved upon to the tune of at least 1 whole year and 2 years respectively -- which we aren't surprised about given that we packed all our schedules with plenty of surplus margins.I thought the committee stated or implied in one of the recent meetings that none of the options could reduce the gap before 2016 or something like that. Why would they say that if DIRECT can be ready for LEO in 2013? Can we conclude that the committee believes that Orion is the long pole?
http://www.space.com/news/090730-ft-moon-budget.html Augustine Committee Says Moon Within Reach