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?
QuoteSo why develop block II if not needed for Lunar?That's what Congress wants. If the aim is Block II, then that is what should be developed. Once developed, it can be flown in a Block IB configuration if desired.
I wonder how high risk would refueling the EUS be as that could greatly increase the TLI payload?
Here's some preliminary artwork to whet your appetite.
I too would prefer a single-launch Lunar mission like 'the good old days'. But forgive me if I missed anything at some stage: have you ever crunched the numbers for a Lunar mission done with dual launches of an SLS Block 1B or similar? I know that would be an expensive mission; though it should allow for a much bigger LM for pretty long stay times on the surface. Also; should allow cargo-only LM versions in single launches of a Block 1B.
That's a whole lot of rocket for an Apollo "flags and footprints" redux. Heck, SLS is a whole lot of rocket anyways and that's a problem IMO. I previously asked about your excessive core stage's drymass of 123.6mT and your J-2X US at 16.9mT seems quite light. I started with different assumptions, resulting in different masses for each and a different, though just as capable rocket. If you'd allow me ..........
Funding wise; The existing EUS and Advanced Booster programs would be cancelled and resources allocated to common bulkhead development, production and re-engineering the business-end of the SHLV. You proposed and outlined the importance of J-2X (as have I and others), but I'd also cancel the RS-25 program, switch AR's production contract to J-2X and use RS-68s on the core with almost no modifications.
I did not investigate using RS-68 since that would need to be redesigned so that the ablative nozzle (which won't survive the base heating conditions) is replaced with a regenerative nozzle, practically making it a new engine.
He did know better?! That's why he didn't 'use' RS-68s in his proposal. Read about what happened in 'Constellation' history...
Quote from: MATTBLAK on 07/24/2017 01:08 pmHe did know better?! That's why he didn't 'use' RS-68s in his proposal. Read about what happened in 'Constellation' history... Comparing the thermal environment of a 10m core with six engines to an 8.4m core with three engines is as ridiculous as comparing it to a 5m core with one engine, and you needn't be a rocket scientist to know that. SP's work and knowledge deserves respect, but making such a comparison seems -- disingenuous.He, and you, should know better. Quoting an agenda's line doesn't excuse it either.
Quote from: Propylox on 07/25/2017 01:34 amComparing the thermal environment of a 10m core with six engines to an 8.4m core with three engines is as ridiculous as comparing it to a 5m core with one engine It doesn't matter. It was the SRMs that created a thermal environment that is incompatible with the ablative nozzles.
Comparing the thermal environment of a 10m core with six engines to an 8.4m core with three engines is as ridiculous as comparing it to a 5m core with one engine
Here is the mission poster. A big thankyou to Michel for getting this done. There are still a number of things that are not correct, but Michel has other projects to do and I didn't want to take up more of his time. I'll let the NSF reader pick all the errors out!
I like the lander, far better than Altar, just not a fan of the crasher stage but OK for a few exploration type missions.
It honestly looks like a 21st century re-imagining of Apollo, utilizing a crasher-stage but nonetheless. I don't know whether to say it's a good or bad strategy, but on the positive I will say it looks feasible at a glance while on the negative easily as wasteful as Apollo. All the same I wouldn't mind seeing this become a reality barring better ideas materializing.
I'd wish for some context on this to make a better call. For example: what kind of orbit will Orion and the lander initially brake into? We already know the Orion can just barely brake into high orbit (and all the weird variants of it); does this imply the crasher-stage, much like Altair's planned descent stage, will be doing much of the inbound work? A second example would be knowing whether or not if either half of the lander can be reused or given some long-term function.
... I'd like to see a version that's one-piece (sans crasher) and reusable.
Sad, but that is no bigger than Apollo. To get anything real done on the moon, they will need a lot of cargo. Block II of SLS should at least ditch the solids for two 5.5 Kerolox boosters using AR-1's at the very least. This alone would increase payload. Then add a 5th engine on the core with a J2X upper stage. Then we are talking real cargo and equipment. IF, big if, the AR-1 is developed, built, and tested. NASA should seriously consider this. They have already developed the J2X, and the extra plumbing for another engine shouldn't be that big a problem for them. They could also recover the engines, like Vulcan, on the AR-1's.
Quote from: spacenut on 08/03/2017 12:16 pmSad, but that is no bigger than Apollo. To get anything real done on the moon, they will need a lot of cargo. Block II of SLS should at least ditch the solids for two 5.5 Kerolox boosters using AR-1's at the very least. This alone would increase payload. Then add a 5th engine on the core with a J2X upper stage. Then we are talking real cargo and equipment. IF, big if, the AR-1 is developed, built, and tested. NASA should seriously consider this. They have already developed the J2X, and the extra plumbing for another engine shouldn't be that big a problem for them. They could also recover the engines, like Vulcan, on the AR-1's. A cargo only version could be made of the lander.By only sending the cargo lander and no crew ( Orion ) this could deliver a greater payload mass and volume to the Lunar surface.
Only real difference, other than layout, is landing legs and I was wondering if you could explain why canting and travel aren't necessary.
Quote from: Steven Pietrobon on 08/03/2017 07:07 amHere's a three view of the LM. Thanks again to Michel Lamontagne. Real impressive work, SP.The math doesn't change, though it's still surprising how similar your design is to the conclusions I and others have reached. For example; If the main tankage mass was excluded, your lander is only a couple hundred kg heavier than my Propulsion+Habitat mass, easily accounted for by your docking ring or third ascent engine. I also planned a 3.25m x 2.8m (L x W) hab compared to your 3.25m x 2.4m (?) when measurements exclude your protective suit cover and leaning viewport. Only real difference, other than layout, is landing legs and I was wondering if you could explain why canting and travel aren't necessary.
Here's a three view of the LM. Thanks again to Michel Lamontagne.
The legs have about 600mm of vertical travel. I expect some kind of self leveling system will be included. ... That being said I didn't actually calculate them, so I might be wrong.
Michel Lamontagne from Canada has been doing some fantastic work on providing artwork of the launch and landing sequence. Here's some preliminary artwork to whet your appetite.
Another option you could get a large cargo lander by adding legs to the EUS like this proposal with the S-IVB.https://www.wired.com/2012/11/skylab-on-the-moon-1966/
The uncrasher stage can have very low dry mass as there is no need for redundant systems. If there is propulsion failure on descent, lander separates and returns EML1. This allows a single BE3 to be used while Xeus needs redundant engines.