brihath - 8/1/2008 11:43 AMI voted for number 4. I'm not in the space industry, but I was responsible for making sure a SAC bomb wing kept its planes flying and on SIOP alert when I was in the AF. I always had a credo that if it looks like it should fly, it generally should fly.The DIRECT concept builds on 25+ years of Shuttle experience, so much of the vehicle has been flight proven and it minimizes the design changes from STS, while ARES 1 is a completely different story. If we want to minimize the manned spaceflight gap, we should go with what we know and minimize the risks, especially in the current budget environment. It's not really that new, as shuttle derived concepts have been bandied about for years.My only concern with this answer is that a "peer-reviewed" process could become just another bureaucratic dead end that kills a potentially successful flight program. It's been done before.Finally, anything we do regarding the manned spaceflight gap should minimize any reliance we have on Russia. I know we have developed an excellent record of cooperation, but the political winds can change in a heartbeat, and we will be left out in the cold. It should definitely NOT be something we plan on doing.
John Duncan - 9/1/2008 9:31 AMMuch depends on who gets the POTUS seat in 09. Programs from previous administrations tend to be poisonous to new ones. Whoever gets in will most likely take a step back from VSE. I just hope that there's a little political pressure from the space contractor constituents to keep *some* kind of a program running. DIRECT would be a good choice.I'm just fearfull that exploration will be pushed aside for the numerous new government freebies that are likely to appear no matter who gets control.
clongton - 9/1/2008 2:09 PMTo all those who have either selected or are considering selecting option 3 (If accepted the DIRECT would require major overhaul), would you mind telling us what the things are that you believe would be so affected? That will provide us with the opportunity to take a look at them and then provide you with a considered response. Perhaps we have overlooked something. If so, we would certainly like to know about that.Thanks
clongton - 9/1/2008 3:09 PMTo all those who have either selected or are considering selecting option 3 (If accepted the DIRECT would require major overhaul), would you mind telling us what the things are that you believe would be so affected? That will provide us with the opportunity to take a look at them and then provide you with a considered response. Perhaps we have overlooked something. If so, we would certainly like to know about that.Thanks
PaulL - 9/1/2008 9:51 PMQuoteclongton - 9/1/2008 3:09 PMTo all those who have either selected or are considering selecting option 3 (If accepted the DIRECT would require major overhaul), would you mind telling us what the things are that you believe would be so affected? That will provide us with the opportunity to take a look at them and then provide you with a considered response. Perhaps we have overlooked something. If so, we would certainly like to know about that.ThanksThe reason I choose option 3 is not that the Direct rockets are bad, but rather the proposed use of them does not match the current NASA philosophy. There is no way NASA will include propellant refuelling/transfer in space on its reference mission to the moon. Also, NASA wants to be able to send as large as possible unmanned payloads to the moon. On that point, the current J-232 rocket payload capacity is probably below what NASA wants. If NASA were to switch from ARES to Direct, I would see them transforming the Direct plan to match the Ares I/V concept: Ares I being replaced by the J-120 which is simpler/safer than the J-232 for manned flights and boosting the J-232 payload capacity as much as possible (with 106% RS-68 and J-2X engines for example). They could even possibly upgrade the J-232 to a J-242 in order to gain an extra 6-7 mT of LEO payload. A J-120/J-242 lunar mission using upgraded engines should be able to surpass the payload capacity of the Ares I/V moon mission.PaulL
kraisee - 7/1/2008 8:29 AMQuoteJIS - 7/1/2008 2:16 AMAll I wanted to hear is how you get those numbers and if you compared them with other systems which actually went through detailed analysis. ESAS numbers were proved to be quite optimistic taking some estimated weight and applying just overall margin. Quote...Try to look at Jupiter elements weight like core, fairing and EDS and find whether they are comparable with elements from operational launchers or launchers which went at least through some basic NASA analysis. I tried that and wasn't convinced. I'm citing what I was told by one Direct proponent: "You don't need to be genius to do that."Until then I simply can't BELIEVE your numbers and have to leave this thread.Without our arbitrary 10% structures margin, but still including the full GR&A Weight Growth Allowance (WGA), our Core Stage would actually mass 64,412kg, not 69,369kg as presented in the AIAA paper. ....At this point, I would refer the gentle reader to the NLS-1 papers I mentioned previously. Being a similar configuration, but powered by three SSME-class engines, and without a large Upper Stage, it's Core Stage would have massed 54,621kg (including 1.4 factor, very similar GR&A's and standard WGA) - some 15 tons lighter than Jupiter's Core, yet still based on LWT, not SLWT. Bringing in much of SLWT mass savings to NLS to bring the two "as manufactured" systems into technological comparison, Jupiter's Core is specified to mass about 18mT more than the NLS Core would have. Again, I would like to find ANYONE who doesn't think this is sufficient additional "bracing" (considering most of the strength is derived from the pressurization of the tanks, not the actual structure itself) to support the extra weight above?
JIS - 7/1/2008 2:16 AMAll I wanted to hear is how you get those numbers and if you compared them with other systems which actually went through detailed analysis. ESAS numbers were proved to be quite optimistic taking some estimated weight and applying just overall margin.
...Try to look at Jupiter elements weight like core, fairing and EDS and find whether they are comparable with elements from operational launchers or launchers which went at least through some basic NASA analysis. I tried that and wasn't convinced. I'm citing what I was told by one Direct proponent: "You don't need to be genius to do that."Until then I simply can't BELIEVE your numbers and have to leave this thread.
Frankly, I'm sick-to-the-back-teeth of people whining about things they "can't believe", people who seem to have very little grasp of the realities and who very often "conveniently" forget things which we've told them specifically about over and over again.
If you have serious technical concerns or questions, bring them, in fact we welcome them because we're always on the hunt for anything we might have missed. But this *constant* negative "can't work" attitude is mind-numbingly tedious and excruciatingly annoying. Please quit it.Ross.
CFE - 9/1/2008 9:21 PMI also think that the upgraded RS-68's (A and B models) should be baselined as soon as practical.
JIS - 7/1/2008 12:56 PMQuoteThe question is not useful so I decline to vote or add voting options.It's for the purpose to find how many naysayers and supporters are visiting this forum and how many of them are willing to admit that. If you don't vote I think you could be just undecided or didn't read that study. Please, add appropriate option and vote for it.
The question is not useful so I decline to vote or add voting options.
JIS - 10/1/2008 5:59 AMThe major finding for myself is the confirmation that many people opposing Direct do not want to take part in the discussion. I can understand that.