They show the 200ton+ launch vehicles from DRM1 and explain why they're traded out.The Magnum is introduced which is less capable than the SLS to LEO (85mt) but has a nuclear TMI stage.... Without further ado I give you DRM3.
I'm sure the SLS production rate could be increased from one vehicle every two years with more budget, but it's hard to see how it could be increased nearly four-fold (for DRM5) or nearly ten-fold (for DRM3).
The bottleneck is really the launch infrastructure, which as we've seen can easily handle 10 launches per year.
NASA is designing SLS with the expectation of a launch rate of two per year at design maturity. They've said as much.
The reason SLS doesn't launch often is that it has nothing to do... the White House and OMB are at least as guilty as Congress.
If they have to upgrade some of the production infrastructure back up to near Shuttle levels, so be it; it's just money...
Quote from: 93143 on 09/11/2013 12:59 amThe bottleneck is really the launch infrastructure, which as we've seen can easily handle 10 launches per year.Assuming GAO weighs in soon on the Blue Origin/SpaceX spat, before the year is out, the pads available to SLS will be cut in half (from 2 to 1) from what STS enjoyed.
QuoteIf they have to upgrade some of the production infrastructure back up to near Shuttle levels, so be it; it's just money... Even if there wasn't such a huge disconnect between SLS production requirements and SLS flight rate expectations (or Mars DRM requirements), money is still a problem. If OMB, the White House, and Congress aren't providing enough funding to give SLS payloads and missions, there won't be any funding to increase SLS production, either.
Shuttle-derived systems with two pads available are known to be able to launch at least 10-12 times per year without trouble, possibly a lot more.
Which leaves the known achievable launch rate at... whaddya know: exactly ten times the frequency you said they could never ever multiply by 4, never mind 10.
You're conflating "can't" and "won't".
The STS annual flight rate peaked at 9 in 1985.
The average annual flight rate for STS was 4.5 flights per year (135 missions over 30 years).
The actual, proven, annual launch rate for Shuttle systems is less than one-half to slightly more than one-third of what you think it is in theory.
it's hard to see how SLS will not suffer from many of the same, multi-month schedule delays as STS when they use many of the same subsystems (LH2 leaks in tanks and RS-25x engines, ET/core structure cracks, etc.).
given ~45 years of NASA budget history post-Apollo never providing anything close to those kinds of resources
QuoteYou're conflating "can't" and "won't".I'd put it a different way.
The world needs hope, but I don't think it's a good foundation upon which to build a multi-billion dollar engineering development program.
What I'd like to see is a study supporting use of HLVs when the budget is flat or slightly declining at current levels.
...Quote from: Robotbeat on 09/11/2013 04:34 pmWhat I'd like to see is a study supporting use of HLVs when the budget is flat or slightly declining at current levels.Is there a study that says any exploration is possible with slightly declining budgets? Remember, most of NASA's budget is stuff other than manned spaceflight and exploration systems...
[Remember also that Congress doesn't fund NASA - Congress funds programs at NASA. Eliminate a program, and the funding disappears. Especially if the reason the program is eliminated is so it can be replaced with a different one that does the same thing but without satisfying anyone important's political interests...]As for flat, SLS/Orion development is around $3B per year, and if NASA isn't blowing smoke with their $500M number for one launch per year (which is possible), the system should be a lot cheaper in operation, at least at a low flight rate. That could free up a couple billion per year for payload development, procurement and launch...
In the perennial debate between SLS and alternatives (either smaller rockets combined with propellant depots or commercially-managed HLVs such as Atlas V Phase 2), depot supporters often point to three studies in particular (Zegler & Kutter 2010, the leaked NASA internal study of 2011, and Wilhite et al. 2012). Which studies compare alternatives and don't recommend depots? I'm aware of ESAS of 2005, which of course recommended Ares V (in addition to Ares I). There is also the study that Administrator Bolden mentioned in House testimony in 2011, but this seems never to have been made public and I'm not certain it actually exists. Can anyone point to other studies that consider the options for one sort of BEO mission or another and do not recommend depots?Please note that I am looking for pointers to studies only. Please let us not debate HLVs and depots in this thread.
$500 million is the "marginal" cost
Quote from: Proponent on 09/10/2013 01:56 amIn the perennial debate between SLS and alternatives (either smaller rockets combined with propellant depots or commercially-managed HLVs such as Atlas V Phase 2), depot supporters often point to three studies in particular (Zegler & Kutter 2010, the leaked NASA internal study of 2011, and Wilhite et al. 2012). Which studies compare alternatives and don't recommend depots? I'm aware of ESAS of 2005, which of course recommended Ares V (in addition to Ares I). There is also the study that Administrator Bolden mentioned in House testimony in 2011, but this seems never to have been made public and I'm not certain it actually exists. Can anyone point to other studies that consider the options for one sort of BEO mission or another and do not recommend depots?Please note that I am looking for pointers to studies only. Please let us not debate HLVs and depots in this thread.Q: Is your question directed at LVs in between the 20 mT class and the 70 mT class?Q: Are both "depots" and "refueling stages" excluded.Q: For lunar only or for Mars class missions? (one could possible have a two launch ~50 mT for the moon).
Q: Is your question directed at LVs in between the 20 mT class and the 70 mT class?Quote from: muomega0 on 09/11/2013 08:22 pmQuote from: Proponent on 09/10/2013 01:56 amIn the perennial debate between SLS and alternatives (either smaller rockets combined with propellant depots or commercially-managed HLVs such as Atlas V Phase 2), depot supporters often point to three studies in particular (Zegler & Kutter 2010, the leaked NASA internal study of 2011, and Wilhite et al. 2012). Which studies compare alternatives and don't recommend depots? I'm aware of ESAS of 2005, which of course recommended Ares V (in addition to Ares I). There is also the study that Administrator Bolden mentioned in House testimony in 2011, but this seems never to have been made public and I'm not certain it actually exists. Can anyone point to other studies that consider the options for one sort of BEO mission or another and do not recommend depots?Please note that I am looking for pointers to studies only. Please let us not debate HLVs and depots in this thread.Q: Is your question directed at LVs in between the 20 mT class and the 70 mT class?Q: Are both "depots" and "refueling stages" excluded.Q: For lunar only or for Mars class missions? (one could possible have a two launch ~50 mT for the moon).Basically what I'm looking for is studies which conclude "It's better to use a Shuttle-derived HLV to perform mission X than to use Y," where Y is anything. Actually, any studies concluding "It's better to use an HLV to perform mission X than to use Y" would also be of interest.
They could fly 100 SLSes a year with a big enough budget.