At the end of a lecture and presentation that I gave for
Starfest 2012 at Bays Mountain Planetarium, I was asked for sources of
information concerning practical deep space exploration options that make more
budgetary and implementational sense than options that would involve either of the
two proposed versions of the SLS launcher.
Next I would suggest NASA’s own groundbreaking study known as Propellant Depot Requirements Status Report. This study was released before SLS was formally named and the designs of both models of SLS were yet to be finalized, though it was already known that the final model of SLS (now known as Block II) would be Shuttle-derived and have an orbital payload capacity in excess of 100 metric tons. The points made in this study are still very relevant if the reader just considers all references to a SDV HLLV as being SLS Block II.
A group of scientists and engineers at Georgia Tech produced the latest paper, which does a direct comparison of using existing commercial launchers for deep space exploration versus using either model or both models of SLS (Block I and Block II) for that purpose. This paper, called Evolved Human Space Exploration Architecture Using Commercial Launch/Propellant Depots starkly reveals both the economic and functional disadvantages of SLS. Anyone who peruses either this study or the earlier NASA study will plainly see what a threat to American spacefaring supremacy that SLS constitutes. In fact, it closes with the conclusion that going the alternate route that does not include SLS “provides experienced and focused workforce to improve safety, operational learning for reduced costs and higher launch reliability, reduce launch costs …”
Many thanks to Clark Lindsey of New Space Watch, for making the last paper available to the public via the internet.
Very interesting blog post. I'm a supporter of commercial space, but I'm actually neutral on the question of the SLS. The reason is because I think commercial space will continue whether or not SLS continues to be funded.
ReplyDeleteFor supporters of the SLS here's a key capability it will have:
SLS for Return to the Moon by the 50th Anniversary of Apollo 11.
http://exoscientist.blogspot.com/2012/10/sls-for-return-to-moon-by-50th.html
The argument for why this is doable is rather simple. The Early Lunar Access(ELA) proposal of the early 90's, which deserves to be better known actually, suggested that by using a lightweight 2-man capsule and all cryogenic in-space stages that a manned lunar lander mission could be mounted with only 52 mT required to LEO, half that previously thought necessary.
The only technical complaint about its feasibility was that it required a crew capsule of only 3 mT empty weight. But the kicker is NASA is planning a Space Exploration Vehicle(SEV) at that same low 3 mT empty weight. So the very first version of the SLS scheduled to launch in 2017 at a 70 mT payload capability will be able to launch such a mission using the SEV as crew capsule following the ELA architecture with plenty of margin.
Bob Clark
I had heard there were some problems to resolve about the core stage but I had not heard about a definite delay.
DeleteAbout cheaper ways of doing it, I agree. As I said in my blog post Falcon Heavy could also accomplish it following the ELA architecture. If there could be a private way of funding this I would be all for it. I don't think NASA would fund it though while SLS is still extant.
If for what ever reason SLS gets canceled, then NASA might consider such a Falcon Heavy based lunar mission.
Bob Clark
@Bob
Delete"If there could be a private way of funding this I would be all for it. I don't think NASA would fund it though while SLS is still extant.
If for what ever reason SLS gets canceled, then NASA might consider such a Falcon Heavy based lunar mission."
Of course, NASA would not fund it while SLS is still extant. SLS most certainly WILL be EVENTUALLY canceled for reasons stated in the Booz-Allen-Hamilton report. The original Obama space plan called for a heavy-lift vehicle, but NOT a shuttle derived heavy-lift vehicle. In fact, the Obama admin did NOT want a "shuttle-derived" heavy-lift vehicle. However, that was the price a group of Senators demanded to allow Commercial Crew to ISS to happen. It was either bow to the Senator's demands or no Commercial Crew program. If Obama wins re-election, you can bet that as soon as SLS slips enough years and makes little progress for the billions spent, that will be all the excuse they need. It may very well happen under a Romney administration with sequestration looming the way it is.
My earlier answer to Bob on November 4 2012 had a sentence that was in error. Since I cannot edit my comments after I post them, I had to delete that entire comment and repost a corrected one. Thus, Bob’s response to this comment appears here before the comment that prompted his reply.
DeleteHi Bob,
In answer to your comment:
"The only technical complaint about its feasibility was that it required a crew capsule of only 3 mT empty weight. But the kicker is NASA is planning a Space Exploration Vehicle(SEV) at that same low 3 mT empty weight. So the very first version of the SLS scheduled to launch in 2017 at a 70 mT payload capability will be able to launch such a mission using the SEV as crew capsule following the ELA architecture with plenty of margin."
That is the only technical complaint from an "engineering" standpoint. There is a much more crippling complaint that is economic in nature rather than technological. The real problem is what the independent Booz-Allen-Hamilton report (that was commissioned by NASA) pointed out. That problem is that development of SLS block I (70 mt) will exhaust its budget within five years while simultaneously slipping behind schedule. http://www.nasa.gov/pdf/581582main_BAH_Executive_Summary.pdf Furthermore, that study indicated that there may never be a functioning SLS as its development gets stretched longer and longer, year after year. Plans such as the one you reference ignore the economic realities of SLS.
Did you not notice that the studies I listed show that we don't have to wait for SLS to be finished to do lunar missions or any other kind of deep space mission? Why wait for SLS to fly (an event that probably won't occur) when we could do deep space missions sooner, CHEAPER, and SAFER without SLS and without having to raise NASA's budget?
Hi! What's your opinion on who are your blog's average subscribers?
ReplyDeleteMy opinion of my blog's average subscribers in what particular regard(s)?
Delete