IMO 2 SLS 1B are only wasteful if you cannot utilize their performance entirely.
@RocketmanUSWhile I somewhat agree that NASA should try to avoid "building" rockets, what commercial options do they have for the payload mass they're talking about? Should they wait for SpaceX's BFR? What happens if it doesn't come to fruition, and if it does, what kind of political fallout would ensue in the event that it's a failure? Besides that, they have no other options.While I do think the SLS is unwarranted for the time being as it doesn't even have any definitive missions, nevermind the extreme cost, I do understand why NASA wants to design a rocket to their spec (and of course you have some in congress demanding it). Sure, they could pour that money in expediting BFR development, but there would be [somewhat understandable] cries coming from all corners of aerospace and government regarding such subsidies of one company, and I doubt SpaceX would want to share development with anyone else on that project.
Shouldn't a lander of such size be capable of delivering significantly more mass to the surface than your solution? For a quick sortie that may not matter, but if you want to build and resupply an outpost...
Downside is that two widely spaced launches with LEO rendezvous has major boiloff issues. LOR and a lander with storable prop seems to me to be the method which requires the least development money to implement.
...SLS could only launch twice a year and that would use up all SLS flight for five plus years for the eleven missions just for Lunar.
Quote from: RocketmanUS on 07/21/2015 04:27 am...SLS could only launch twice a year and that would use up all SLS flight for five plus years for the eleven missions just for Lunar.Just a slight clarification -- they can only, at this time, make two SLS boosters a year. If several are made up in advance, the latest thinking is that they could be launched every 120 days in "salvo" mode, meaning with present construction and launch flow capability, they could launch three a year. And if a program was funded that required a higher flight rate, assuming you could make enough of them, you could increase that flight rate to up to five or six launches a year, based on the capability proven during Apollo to be able to launch every 60 days off of one pad. (Yes, they did ease their constraints somewhat by launching Apollo 10 from 39B, but could easily have kept to the same launch schedule and only used 39A if they had chosen to do so.)
Quote from: Oli on 07/20/2015 07:01 amShouldn't a lander of such size be capable of delivering significantly more mass to the surface than your solution? For a quick sortie that may not matter, but if you want to build and resupply an outpost...I haven't crunched the numbers, but I would expect a dual Block IB mission to be able to land more cargo. Afterall, you are putting 186 t into LEO compared to 140 t.
Quote from: Steven Pietrobon on 07/21/2015 07:00 amQuote from: Oli on 07/20/2015 07:01 amShouldn't a lander of such size be capable of delivering significantly more mass to the surface than your solution? For a quick sortie that may not matter, but if you want to build and resupply an outpost...I haven't crunched the numbers, but I would expect a dual Block IB mission to be able to land more cargo. Afterall, you are putting 186 t into LEO compared to 140 t.Dual block 1B (RSRMV + EUS with RL10C) would be 210-225t to LEO, and ~80t through TLI. Cheers, Martin
Dual block 1B (RSRMV + EUS with RL10C) would be 210-225t to LEO, and ~80t through TLI.
What would one SLS block IB get through TLI?
So could it get Orion into LLO?
Could it get Steven's Lunar lander to Lunar surface? If so then could get rovers ( probe ) before crew landings and test out the lander.
On descent to Lunar surface were is the CPS attached to the Lunar lander ( top or bottom )?
Quote from: RocketmanUS on 07/24/2015 07:05 pmWhat would one SLS block IB get through TLI?Not including the EUS, payload is 39 t. Including the EUS, payload is 51 t.QuoteSo could it get Orion into LLO?Yes, no problem.QuoteCould it get Steven's Lunar lander to Lunar surface? If so then could get rovers ( probe ) before crew landings and test out the lander.You would use a large Apollo type lander using storable propellants. Rovers and payloads would be stored in the triangular payload compartments in the descent stage.QuoteOn descent to Lunar surface were is the CPS attached to the Lunar lander ( top or bottom )?You can't use the EUS, as the Lander would be waiting for several months in LLO for Orion to arrive. All its propellant would boiloff.
So SLS block IB could get an Apollo style LEM on the Lunar surface with about 50% increase in payload mass ( cargo ) or a 3 crew ascender?
For your SLS block II were is your lander attached to the CPS on descent to Lunar surface ( on the landers bottom or top?
So why develop block II if not needed for Lunar?