SLS General Discussion Thread 8

[mike robel]

Well, I have two observations.

1.  The planning horizon has changed from Mars: 30 years in the future to Mars:  18 years into the future.
2.  It seems to me, it would be Faster, Better, Cheaper (choose 2) for NASA to team up with SpaceX since NASA will be using Starship, in some fashion, for Lunar Surface Missions so why not use the SpaceX plan for Mars instead of another expensive government project?

[DanClemmensen]

Well, I have two observations.

1.  The planning horizon has changed from Mars: 30 years in the future to Mars:  18 years into the future.
2.  It seems to me, it would be Faster, Better, Cheaper (choose 2) for NASA to team up with SpaceX since NASA will be using Starship, in some fashion, for Lunar Surface Missions so why not use the SpaceX plan for Mars instead of another expensive government project?

This is off-topic for this thread. SLS/Orion is a congressionally-mandated zipcode-specific program to fund OldSpace at the rate of $4 Billion/yr + 4.1 Billion per launch. NASA/SpaceX can send all the missions they want to Mars using whatever hardware they please, but they must continue to fund SLS/Orion at that rate. Results are irrelevant.

[yg1968]

The reason that there should be a clear distinction between SLS and Artemis is that Artemis is a program to visit the Moon and the SLS is a rocket. There should be a distinction there. If for some reason SLS fails, we don't want to throw the entire lunar program out the window and start again from scratch (again).

Going on to Mars is a notional goal of Artemis, but AFAIK, no funding has been allocated and no official plans exist at all. Without either of those two, it's just talk. As half a century of power point presentations have taught us, having detailed plans of how to get there isn't any good without the cash to pay for the hardware and support systems. It's tired, and it's cliche, but it's true: 'No bucks, no Buck Rogers.'

There are plans for Mars. See pages 37-44 of this document:
https://ntrs.nasa.gov/api/citations/20210022080/downloads/HEOMD-007%20HEO%20SCOPE%20-%2009-28-2021%20NTRS.pdf

Oh please. Just because someone at NASA writes a paper that says that Mars is a goal does not make it a REALISTIC goal for NASA, especially if they have to use the SLS.

As a reminder, for the lunar-oriented Artemis program the SLS is only needed for launching the Orion MPCV, and the Orion MPCV is not designed for going to Mars. So for the purposes of this thread, the SLS is not needed for any effort to go to Mars.

If you actually read the document instead of dismissing it, you would realize that SLS and Orion will actually be used for Mars. Orion brings the crew to LDHEO (Lunar Distance High Earth Orbit) where the DST (Deep Space Transport) will be waiting for it. The DST then brings the crew to Mars vicinity.

First crewed Mars mission will consist of 4 crew; 2 crew to remain in Mars orbit, 2 crew to the Mars surface, exploring on the surface while living in a small pressurized rover.

To meet a Mars crew departure in 2039, beginning in 2032, the SLS launch rate increases (see HEOMD-004, ESD-R-15, Launch Rate).

The crewed mission phase involves all operations to transport the crew to Mars vicinity on the DST, descend two crew members to the surface, return those crew members to the DST, and to safely return the crew to Earth. Crew operations (transfer methods and associated devices) to be used at Mars will be tested in Lunar analog studies.

The mission begins with launch of the crew on SLS and Orion to rendezvous with the DST in LDHEO. The crew will begin launch attempts 90 days prior to the Mars departure date to allow for launch delays and multiple launch opportunities. After the crew rendezvous with the DST, they transfer time-critical logistics and perform the final checkout in LDHEO. The DST then performs a chemical burn to depart LDHEO.

The second lunar gravity assist maneuver will capture the vehicle into a lunar distance high Earth orbit (notional 400 x 400,000 km), where it will rendezvous with an uncrewed Orion vehicle and return the four crew to Earth. This architecture assumes that the Orion vehicle is already in orbit when the vehicle enters the high Earth orbit, and that the rendezvous, docking, and transfer of crew supportability to the Orion takes no more than 10 days.

https://ntrs.nasa.gov/api/citations/20210022080/downloads/HEOMD-007%20HEO%20SCOPE%20-%2009-28-2021%20NTRS.pdf

[Coastal Ron]

Oh please. Just because someone at NASA writes a paper that says that Mars is a goal does not make it a REALISTIC goal for NASA, especially if they have to use the SLS.

As a reminder, for the lunar-oriented Artemis program the SLS is only needed for launching the Orion MPCV, and the Orion MPCV is not designed for going to Mars. So for the purposes of this thread, the SLS is not needed for any effort to go to Mars.

If you actually read the document instead of dismissing it, you would realize that SLS and Orion will actually be used for Mars. Orion brings the crew to LDHEO (Lunar Distance High Earth Orbit) where the DST (Deep Space Transport) will be waiting for it. The DST then brings the crew to Mars vicinity.

Yes, I'm aware that lots of different justifications have been used over the years for including the SLS+Orion in a planned Mars campaign, including this latest iteration (previous ones had the Orion going to Mars).

However ANY use of the SLS+Orion is too expensive and too launch-rate limiting to be used for a Mars campaign.

It really baffles me why any space enthusiasts would support the continued use of expendable and non-reusable space transportation systems, when so much more human space exploration could be done with partially and fully-reusable transportation systems - including space-only reusable transportation systems that could easily replace the SLS+Orion.

Mars is unobtainable for NASA if it has to use the SLS. It is under-powered for supporting the Artemis Moon mission, and would be completely unusable for a Mars mission. So NASA PR about using the SLS for a mission to Mars is, to me, just paid advertising for Boeing et al.

[yg1968]

It really baffles me why any space enthusiasts would support the continued use of expendable and non-reusable space transportation systems, when so much more human space exploration could be done with partially and fully-reusable transportation systems - including space-only reusable transportation systems that could easily replace the SLS+Orion.

I didn't say that I support it but it would be interesting if the Deep Space Transport was commercial and Starship was chosen for that role.

[DanClemmensen]

It really baffles me why any space enthusiasts would support the continued use of expendable and non-reusable space transportation systems, when so much more human space exploration could be done with partially and fully-reusable transportation systems - including space-only reusable transportation systems that could easily replace the SLS+Orion.

I didn't say that I support it but it would be interesting if the Deep Space Transport was commercial and Starship was chosen for that role.

Certainly. Send a 100-person expedition to Mars once every two years. Four of the crew can be delivered to the Starship DST via SLS/Orion. The remaining 96 crew will already be aboard Starship DST, having transferred from a crewed EDL Starship. We can hope that eventually the public will realize how ludicrous this is.

[yg1968]

It really baffles me why any space enthusiasts would support the continued use of expendable and non-reusable space transportation systems, when so much more human space exploration could be done with partially and fully-reusable transportation systems - including space-only reusable transportation systems that could easily replace the SLS+Orion.

I didn't say that I support it but it would be interesting if the Deep Space Transport was commercial and Starship was chosen for that role.

Certainly. Send a 100-person expedition to Mars once every two years. Four of the crew can be delivered to the Starship DST via SLS/Orion. The remaining 96 crew will already be aboard Starship DST, having transferred from a crewed EDL Starship. We can hope that eventually the public will realize how ludicrous this is.

Your post made me laugh but I would expect that this DST-Starship would only carry 4 crew. Furthermore, it seems that initial crewed Starships will only carry 12 people.

[Zed_Noir]

It really baffles me why any space enthusiasts would support the continued use of expendable and non-reusable space transportation systems, when so much more human space exploration could be done with partially and fully-reusable transportation systems - including space-only reusable transportation systems that could easily replace the SLS+Orion.

I didn't say that I support it but it would be interesting if the Deep Space Transport was commercial and Starship was chosen for that role.

Certainly. Send a 100-person expedition to Mars once every two years. Four of the crew can be delivered to the Starship DST via SLS/Orion. The remaining 96 crew will already be aboard Starship DST, having transferred from a crewed EDL Starship. We can hope that eventually the public will realize how ludicrous this is.

Your post made me laugh but I would expect that this DST-Starship would only carry 4 crew. Furthermore, it seems that initial crewed Starships will only carry 12 people.

There is one issue with the whole NASA Deep Space Transport concept involving SLS & Orion  that will likely make it a paper project forever. Musk will not wait for NASA if the way is open with Starship being operational. He will likely have enough financial resources to fielded the first few Mars mission himself. Maybe with token NASA representation, if Musk & NASA still gets along. Since it is apparent to me that SpaceX is developing their own Astronaut program.

[Robotbeat]

It really baffles me why any space enthusiasts would support the continued use of expendable and non-reusable space transportation systems, when so much more human space exploration could be done with partially and fully-reusable transportation systems - including space-only reusable transportation systems that could easily replace the SLS+Orion.

I didn't say that I support it but it would be interesting if the Deep Space Transport was commercial and Starship was chosen for that role.

Certainly. Send a 100-person expedition to Mars once every two years. Four of the crew can be delivered to the Starship DST via SLS/Orion. The remaining 96 crew will already be aboard Starship DST, having transferred from a crewed EDL Starship. We can hope that eventually the public will realize how ludicrous this is.

Your post made me laugh but I would expect that this DST-Starship would only carry 4 crew. Furthermore, it seems that initial crewed Starships will only carry 12 people.

Just 4 crew poses higher psychological and medical risks than 12 or 100 crew. With just 4 crew, you don’t have enough people to bring qualified medical personnel if there’s a problem. Especially if you go with the just 2 surface crew as NASA desired. If you dig down into the assumptions behind the desire for very short mission times (independent of radiation dose, etc), it boils down to lack of medical personnel and equipment in case a medical problem randomly arises. Larger crews and more equipment solves this problem.

[DanClemmensen]

It really baffles me why any space enthusiasts would support the continued use of expendable and non-reusable space transportation systems, when so much more human space exploration could be done with partially and fully-reusable transportation systems - including space-only reusable transportation systems that could easily replace the SLS+Orion.

I didn't say that I support it but it would be interesting if the Deep Space Transport was commercial and Starship was chosen for that role.

Certainly. Send a 100-person expedition to Mars once every two years. Four of the crew can be delivered to the Starship DST via SLS/Orion. The remaining 96 crew will already be aboard Starship DST, having transferred from a crewed EDL Starship. We can hope that eventually the public will realize how ludicrous this is.

Your post made me laugh but I would expect that this DST-Starship would only carry 4 crew. Furthermore, it seems that initial crewed Starships will only carry 12 people.

There is one issue with the whole NASA Deep Space Transport concept involving SLS & Orion  that will likely make it a paper project forever. Musk will not wait for NASA if the way is open with Starship being operational. He will likely have enough financial resources to fielded the first few Mars mission himself. Maybe with token NASA representation, if Musk & NASA still gets along. Since it is apparent to me that SpaceX is developing their own Astronaut program.

I did not mean to imply that Starship DST will wait for SLS/Orion. One or more Starship DST will depart during the first Mars launch window it can and in every launch window thereafter. SLS/Orion will deliver 4 crew eventually, probably not during the first Starship DST mission. Its value for SLS/Orion is that is is an achievable target. SLS/Orion needs a target to justify its existence. If NASA wants to send crew on the first Mars Mission, they can buy tickets on Starship EDL. This entire concept is barely more than whimsical speculation at this point, but IMO is more feasible than the NASA paper.

[darkenfast]

The four-person crew with two remaining in Mars orbit tells us just how ridiculous NASA's power-point dreams of a Mars mission are. How many billions will this one two-person short-stay cost?

Boeing, Orbital ATK, and the others are probably drooling over this fantasy.

[tea monster]

Boeing, Orbital ATK, and the others are probably drooling over this fantasy.

They will be, until they realise that by the time Congress decides to pay for a push to Mars and starts issuing contracts, we will all be long dead.

[Zed_Noir]

Boeing, Orbital ATK, and the others are probably drooling over this fantasy.

They will be, until they realise that by the time Congress decides to pay for a push to Mars and starts issuing contracts, we will all be long dead.

Disagree. Unless you expect the SX CTO will not get to Mars for retirement. He have a different timetable for people getting to Mars regardless the progress of the SLS with Orion.

[su27k]

I didn't say that I support it but it would be interesting if the Deep Space Transport was commercial and Starship was chosen for that role.

If Starship is chosen as DST, then it will leave from LEO instead of NRHO and there would be no need to use SLS/Orion for crew transport.

[zubenelgenubi]

Moderator:
Stay on-topic.

[Mackilroy]

Deep Space Transport is the name of the joint venture between Boeing and Northrop for EPOC: https://spacenews.com/nasa-outlines-case-for-making-sole-source-sls-award-to-boeing-northrop-joint-venture/

[tea monster]

Disagree. Unless you expect the SX CTO will not get to Mars for retirement. He have a different timetable for people getting to Mars regardless the progress of the SLS with Orion.

I was speaking solely about Congress eventually deciding to go to Mars, and then funding NASA to hand out contracts to the usual old-space suspects.

[DanClemmensen]

Deep Space Transport is the name of the joint venture between Boeing and Northrop for EPOC: https://spacenews.com/nasa-outlines-case-for-making-sole-source-sls-award-to-boeing-northrop-joint-venture/

Yep, take a completely generic name and claim it is now only to be used for one specific application, like Space Launch System or Space Transportation System. This  makes it hard to discuss the generic concept. And yes, this post is germane to this thread.

[clongton]

There are plans for Mars. See pages 37-44 of this document:
https://ntrs.nasa.gov/api/citations/20210022080/downloads/HEOMD-007%20HEO%20SCOPE%20-%2009-28-2021%20NTRS.pdf

I have read that paper before, and I read it thru again just to be sure, and I hate to say it but that's not going to happen. The only organization that actually will go with crew is not mentioned at all in that paper. Truth be told, NASA is **NOT** going to go to Mars, next year, in 30 years or (I believe) ever, on it's own government dime. The SLS/Orion launch system is not powerful enough, not economic enough, not robust enough to support a manned MARS mission of any kind. It's starting to look like SLS missions will be once every 18 months. How in the world is SLS going to launch often enough to put all the ground equipment on the surface of Mars to support even a paltry 4-crew mission? The moon is hard, but Mars is not only harder, it's also extremely harsh. By the time the crew gets there at that launch rate everything NASA sent there, launched by SLS, will already have exceeded its lifespan. That paper is pie in the sky click-bate. SLS/Orion just can't support all those things. Physics does not lie. Numbers do not lie. Time marches on and doesn't care about our plans. In fact, SLS/Orion is actually THE reason that NASA will not go to Mars! If NASA astronauts ever do get to go to Mars it will not be in a NASA spacecraft. It will be someone else's spacecraft, as THEIR crew or passenger, whom I won't mention so as to not go off topic. -- The bottom line is that SLS/Orion cannot support a crewed Mars mission of any kind. It just can't. The logistics alone are beyond its capabilities.

[VSECOTSPE]

It's starting to look like SLS missions will be once every 18 months. How in the world is SLS going to launch often enough to put all the ground equipment on the surface of Mars to support even a paltry 4-crew mission?

Agreed.  Mars DRM 5.0 required at least 7 launches of a 130t lifter to assemble one mission.  All 7 of those launches have to go off within 26 months.  That will never happen with SLS.  And that was the most optimistic case with nuke-thermal transit.  It only gets tougher from there.  NASA’s current human exploration planning documents are more spin and PR than hard-nosed systems analysis.  It’s really sad/shameful.