Starship variant for crewed Mars ascent

[Vultur]

I get about 540m/s in delta-v to land 100t, but that requires 5 earthgee, which is kinda iffy for a crew that's just spent 6 months in microgravity. 

How significant is that? People do Soyuz reentries after 6 months or even a year+.

They also get carried out of their seats and driven away.  Hard to do that on Mars.

PS:  Let me pose a question:  Is there a component of microgravity de-conditioning that makes a human unable to tolerate high accelerations?

I thought the cosmonauts often made a point of walking out under their own power rather than allowing themselves to be carried?

Anyway, that's more about return to 1 g than the brief g forces of re-entry, which are already over for a while before anybody is getting out of the capsule.

I am not sure if deconditioning is really relevant honestly. People aren't going to be walking/moving much during atmospheric entry g's, so muscle strength loss wouldn't be relevant. Bone loss might potentially be, but if astronauts/cosmonauts re-entering from ISS (or Mir, etc) don't/didn't break bones, it's probably not much of an issue in practice (because they are cushioned and immobile during the g forces). Everything will be automated, so even a g force blackout probably won't matter.

[TheRadicalModerate]

I am not sure if deconditioning is really relevant honestly. People aren't going to be walking/moving much during atmospheric entry g's, so muscle strength loss wouldn't be relevant. Bone loss might potentially be, but if astronauts/cosmonauts re-entering from ISS (or Mir, etc) don't/didn't break bones, it's probably not much of an issue in practice (because they are cushioned and immobile during the g forces). Everything will be automated, so even a g force blackout probably won't matter.

5-6G on connective tissue that's atrophied is going to be pretty painful.  Is it painful enough to prevent astronauts from moving around immediately after landing?  That's really the question.  The good news is that they only have to move around in 3.7m/s².

But there are all kinds of things that require good mobility in the first days after landing.  The most critical are things relating to a stay / no-stay decision.  The Ship needs to be thoroughly inspected, the landing footing evaluated for long-term stability, and certain stuff will need to be deployed successfully before the decision can be made.  A lot of that can be automated, but not all of it.

In the event of a no-stay decision, the crew needs to evacuate the Ship, drive (or possibly walk) to the ascent vehicle (Ship, MAV, makes no difference), prep it for ascent, and then endure yet another relatively high-G acceleration.

I'm guessing that 3G on landing will be just fine.  6G I'm not so sure about.  Hence the question.

[TheRadicalModerate]

Very interesting I hadn't considered the landing in much detail, but perhaps I should. What do you use for the detailed calculations?

I think I have this working.  Make a copy if you want to play with it.

Fields in blue are editable.  Put your Starship parameters in, then use trial-and-error to pick an altitude that works.  It'll tell you whether you're too high, too low, ran out of landing prop, or got it juuuuuust right.

[Slarty1080]

Thanks for that I will have a play when I get a minute.

One further problem I have discovered with the v4 Starship Human landing plan is the lack of space available. If you look at the propellant load of v4 (2300 tons) and height (61m) and compare that to the existing v3 then calculate the additional height required in the tanks for props, most of the cargo bay is consumed. Even allowing for a few metres reduction in the depth of the engine bay and relocating the header tank downwards, space becomes very tight The whole cargo bay will be in the tapering section (along with the forward flap mechanisms).

I will see if I can get an estimate of what space is available.

[TheRadicalModerate]

For the MAV or other cargo that's too big to get out of a hatch, I'm kinda fretting over how to jettison the Starship's nose fairing, either before or after landing.  Numerous problems:

1) You can't jettison the header tanks if you're still using them.  So if there are nose headers, you have to jettison after landing.

2) You have to decide which half the header tanks are going to go with.  Note that you probably need pyros or exotic pressure couplings to shear away or disconnect the header downcomers, near the level of the garage deck.

3) If you split the fairings along the x-z plane (other than the headers), then you need some way to make the fairing halves not land on the tail flaps.

4) Splitting along the x-z plane also requires some extremely exotic way of splitting the TPS into two halves.

5) If you split the fairings along the x-y plane, then you need some way to ensure that the area is clear to deploy and approach the elevator.

6) Splitting along the x-y plane also forces you to decide what to do with the forward flaps:  Do they both go with the ventral half of the fairing, or do you split them so one goes ventral and one goes dorsal?  I think you put them both on the ventral half, but then you need to make sure that the jettison dynamics don't unbalance the Starship.

7) No matter which way you arrange the split, you'll have to separate the thermal blanket under the tiles.  This is a fairly nasty problem, unless you can engineer a clean break in the blanket at the hinge point.  The same goes for the tiles.  But that's an invitation for reentry gases to get in along the split.

Seems like the x-y split is much better to deal with TPS, but you have to accept a transverse straight line in both tiles and the blanket at the garage deck level.  (Without a clean break through the blanket, I don't think this is gonna work at all.)

To deal with the difference in balance (the ventral side has the weight of the flaps and the TPS, while the dorsal side is just bare metal), maybe it makes sense to have some kind of solid rocket assist to launch the halves away from the vehicle.  But if the rockets are mounted on the inside of the fairings (and they have to be to make it through EDL), then the exhaust is going to impinge on the payload.

This is really hard on Mars.  For a cargo HLS going to the Moon, it's pretty easy, because there are no flaps, no headers, and no TPS.  You can jettison the fairing in space and have done with it, as long as your payload can tolerate getting a little dusty.


I wonder if you could have the landing thrusters carry the entire nose and barrel straight up, until they clear the payload.  The thrusters are canted out a ways, so impingement shouldn't be a big deal, but you need extremely good guidance to prevent the fairing from colliding with the payload.

You also need pressure-fed thrusters, and low-profile COPVs to carry the prop needed during the jettison maneuver.

[DanClemmensen]

For the MAV or other cargo that's too big to get out of a hatch, I'm kinda fretting over how to jettison the Starship's nose fairing, either before or after landing.

Ship can carry an Optimus with welding tools and a small winch. Slice the fairing and anything else up there into managable pieces and lower them. Take as long as you need. If it's simpler, use a second Optimus on the ground to handle the pieces as they are winched down. This is mechanically simpler than any complex fairing. The robots do not need to be smart. They have a task that is rigidly planned and programmed.

If leaving the cargo up there above the Ship's tanks is infeasible, you can also lower it by carefully cutting rings out of the Ship below the cargo and lowering it in increments. This is similar to the way a tower crane raises (lowers) itself. This requires several winches arranged around the whole perimeter to lower the top section in two-meter increments.

The power for all this welding must come from somewhere, probably solar panels laid out on the surface before all that slicing happens.

[TheRadicalModerate]

For the MAV or other cargo that's too big to get out of a hatch, I'm kinda fretting over how to jettison the Starship's nose fairing, either before or after landing.

Ship can carry an Optimus with welding tools and a small winch. Slice the fairing and anything else up there into managable pieces and lower them. Take as long as you need. If it's simpler, use a second Optimus on the ground to handle the pieces as they are winched down. This is mechanically simpler than any complex fairing. The robots do not need to be smart. They have a task that is rigidly planned and programmed.

If leaving the cargo up there above the Ship's tanks is infeasible, you can also lower it by carefully cutting rings out of the Ship below the cargo and lowering it in increments. This is similar to the way a tower crane raises (lowers) itself. This requires several winches arranged around the whole perimeter to lower the top section in two-meter increments.

The power for all this welding must come from somewhere, probably solar panels laid out on the surface before all that slicing happens.

If you have that kind of automation at your disposal, it sounds a lot easier just to figure out how to send a propellant factory to the surface, transport the prop to a waiting Starship, and skip the MAV altogether.

For that matter, you could probably ship the MAV as pieces that can fit through the hatch and get the robots to assemble them on the ground.

Both of these still sound like science fiction to me.  I wouldn't rule out science fiction when talking about another ten years of AI and robotics progress before anything happens, but I don't know how to have an engineering discussion about it.

[TheRadicalModerate]

One further problem I have discovered with the v4 Starship Human landing plan is the lack of space available. If you look at the propellant load of v4 (2300 tons) and height (61m) and compare that to the existing v3 then calculate the additional height required in the tanks for props, most of the cargo bay is consumed.

A ring segment holds a bit more than 100t of density-averaged methalox, so you're talking about 7 additional ring segments, each 1.83m high.  So you need 12.8m more tankage.  v4 is supposed to be 11.1m taller than v3, so it sounds like it's in the ballpark to me.  At the very worst, assuming no improvements to the dome and engine skirt heights, you're eating one additional segment from the payload barrel.

The big difference in payload bay height comes between v2 and v3, where they're the same total height, but there are two additional ring segments of tankage for v3. 

I'm not too worried about this.  The v2 payload bay is way, way bigger than it needs to be.  Unlike the fairing volumes for any other launcher, the ogive/nose sections of the bay likely don't impinge on many payloads that would be deployed in space.  And when you come to the garage configuration, I really don't see much need for a cylindrical portion of the garage that's taller than the height of the hatch.

[Slarty1080]

One further problem I have discovered with the v4 Starship Human landing plan is the lack of space available. If you look at the propellant load of v4 (2300 tons) and height (61m) and compare that to the existing v3 then calculate the additional height required in the tanks for props, most of the cargo bay is consumed.

A ring segment holds a bit more than 100t of density-averaged methalox, so you're talking about 7 additional ring segments, each 1.83m high.  So you need 12.8m more tankage.  v4 is supposed to be 11.1m taller than v3, so it sounds like it's in the ballpark to me.  At the very worst, assuming no improvements to the dome and engine skirt heights, you're eating one additional segment from the payload barrel.

The big difference in payload bay height comes between v2 and v3, where they're the same total height, but there are two additional ring segments of tankage for v3. 

I'm not too worried about this.  The v2 payload bay is way, way bigger than it needs to be.  Unlike the fairing volumes for any other launcher, the ogive/nose sections of the bay likely don't impinge on many payloads that would be deployed in space.  And when you come to the garage configuration, I really don't see much need for a cylindrical portion of the garage that's taller than the height of the hatch.

I think v4 is only 8.9m taller than v3 not 11.1 so that makes it difficult. It's not a major issue but it does make it difficult to predict the available space and layout of a human Mars mission at this moment as there are a range of options.

Worst case there is no cargo bay on the first mission and all the cargo plus the MAV has to go on the Autonomous Landing Vehicle or they could use 4 ships. The crew would be pushed up into the nose section. Room for 4 maybe 6, but beyond that it gets increasing cramped.

Better assumptions SpaceX magics some extra space for the crew module / cargo by squeezing the engine compartment or stretching v4 even further which should leave room for a good cargo bay, but still leaves the crew accommodation somewhat cramped.

Best case SpaceX find a lot of extra room by both of these methods and others. But at this point we are off the yellow brick road, we can imagine what we want but the higher we imaging it to be the less likely it is to become reality. An update from Elon Musk or SpaceX would be very useful.

Concerning the MAV on the ALV. Can't they just leave the forward flaps in place? We are not talking a full Starship launch, not even a Raptor launch, it will be fairly modest with stored props. Firstly how much clearance is required? And how much is available? Worst case if it's really necessary, attach a vertical guide way (tube) to either side of the bottom of the MAV that fit comfortably over and two stout vertical rods projecting from the base of the MAV. Or similar - could even have an open v shaped groove mounted vertically using the back of the flap housing as a support and a reverse V rail mounted on the MAV.

On a positive note for both issues, at least we can estimate the available clearance using the SpaceX published cargo bay dimensions. The flaps can't reasonably extend into this volume so there is 4.5-5.0 or more metres of radial space available for a MAV.

[TheRadicalModerate]

I think v4 is only 8.9m taller than v3 not 11.1 so that makes it difficult. It's not a major issue but it does make it difficult to predict the available space and layout of a human Mars mission at this moment as there are a range of options.

Yup, apparently I can't reliably subtract two numbers in my head.

So we're eating about 3 payload ring segments, assuming the v4 numbers are reliable.  Along with the 2 eaten between v2 and v3, that's about 9.5m gone, which would be most if not all of the barrel.

But a 6m-diameter MAV is unlikely to be more than 7m tall, which should fit easily into the static envelope of the ogive.

I still expect at least a couple of cylindrical ring segments in the garage.  Hatches in the ogive are a pain, and the crew needs room to walk around on the garage deck.

Concerning the MAV on the ALV. Can't they just leave the forward flaps in place?

I'm assuming that the MAV isn't stacked as the nose of the Starship, but is instead encapsulated.  You have to get rid of the encapsulation, which includes the headers and forward flaps.

If you stack the MAV as the front of the Starship, that's a bigger deal, but yeah, you could potentially just leave the forward flaps and header in place.  It makes it a lot heavier, though.  And if there it's hard to design a clean jettison for the fairing, it's even harder to ensure a clean separation of the entire nose.

[Vultur]

I am not sure if deconditioning is really relevant honestly. People aren't going to be walking/moving much during atmospheric entry g's, so muscle strength loss wouldn't be relevant. Bone loss might potentially be, but if astronauts/cosmonauts re-entering from ISS (or Mir, etc) don't/didn't break bones, it's probably not much of an issue in practice (because they are cushioned and immobile during the g forces). Everything will be automated, so even a g force blackout probably won't matter.

5-6G on connective tissue that's atrophied is going to be pretty painful.  Is it painful enough to prevent astronauts from moving around immediately after landing?  That's really the question.

Don't we already know the answer is no from Soyuz reentries? and that's in full earth G.

I didn't think the issues with readaptation had to do with pain from the G-forces, but more about balance (plus muscle strength etc).
Scott Kelly's book "Endurance" talks about how the readaptation to gravity is actually worse a couple days after landing. So I'm not sure a 3G reentry vs a 6G reentry makes any meaningful difference to readaptation.

But there are all kinds of things that require good mobility in the first days after landing.  The most critical are things relating to a stay / no-stay decision. 

I'm not sure Mars will work that way. Due to launch windows, abort back may not be an immediate option.  (Well, maybe with opposition class missions?) I think there may well be no decision, stay is "baked in".

[Slarty1080]

I think v4 is only 8.9m taller than v3 not 11.1 so that makes it difficult. It's not a major issue but it does make it difficult to predict the available space and layout of a human Mars mission at this moment as there are a range of options.

Yup, apparently I can't reliably subtract two numbers in my head.

So we're eating about 3 payload ring segments, assuming the v4 numbers are reliable.  Along with the 2 eaten between v2 and v3, that's about 9.5m gone, which would be most if not all of the barrel.

But a 6m-diameter MAV is unlikely to be more than 7m tall, which should fit easily into the static envelope of the ogive.

I still expect at least a couple of cylindrical ring segments in the garage.  Hatches in the ogive are a pain, and the crew needs room to walk around on the garage deck.

The real pain at the moment is not knowing what we have got to play with. On the plus side the v4 is supposed to put 200 tons into orbit. If we only want 100 tons and can play with the positions of the propellant bulkheads, maybe we can wangle sufficient room for a garage or extra deck. Not sure how easy this would be to calculate.

I'm assuming that the MAV isn't stacked as the nose of the Starship, but is instead encapsulated.  You have to get rid of the encapsulation, which includes the headers and forward flaps.

If you stack the MAV as the front of the Starship, that's a bigger deal, but yeah, you could potentially just leave the forward flaps and header in place.  It makes it a lot heavier, though.  And if there it's hard to design a clean jettison for the fairing, it's even harder to ensure a clean separation of the entire nose.

I was also assuming that the MAV was encapsulated. BUT I was also assuming that after landing, everything was jettisoned except the forward flaps and the side supporting structure that connect them to the base of the MAV launch platform. The header tanks must live in the main body of the rocket whatever happens otherwise the whole concept is impossible. With the MAV near the top of the ship I would have thought it wouldn't be a Centre of Gravity issue. I don't see why it can't just launch straight up, with guides if required.

[TheRadicalModerate]

The real pain at the moment is not knowing what we have got to play with. On the plus side the v4 is supposed to put 200 tons into orbit. If we only want 100 tons and can play with the positions of the propellant bulkheads, maybe we can wangle sufficient room for a garage or extra deck. Not sure how easy this would be to calculate.

The only difference between the garage version and the Pez or other payload configurations is that it's designed to move cargo, locked down vertically, through a hatch, under gravity, instead of out of a Pez slot or off of a PAF directly into space.  So the only issue is whether the MAV will fit.

I'm pretty sure it will, even if it's only 6m in diameter.

Again, it's essential that human beings are able to stand, in EVA suits, on the garage deck, without bumping their helmets on the ceiling.  That requires at least 2.5m, especially in low gravity.  So that's a design constraint.  Unless they're not planning on using v4 for Mars, you can count on at least that, plus the ogive and nose cap sections.

I was also assuming that the MAV was encapsulated. BUT I was also assuming that after landing, everything was jettisoned except the forward flaps and the side supporting structure that connect them to the base of the MAV launch platform. The header tanks must live in the main body of the rocket whatever happens otherwise the whole concept is impossible. With the MAV near the top of the ship I would have thought it wouldn't be a Centre of Gravity issue. I don't see why it can't just launch straight up, with guides if required.

I don't know how you'd have free-standing flap structures.  Right now, they're bolted on to the monocoque nose fairing.

I don't think nose header tanks are a deal-breaker, if they're required.  You just have to separate the downcomers before the jettison operation.

No clue what the balance issues will be with v4.  One of the reasons I brought up the landing model is because it informs how much landing prop you need.  If all of that goes into the header/downcomer system, the headers are getting much bigger.  But if only some--or none--of it needs to be in the nose, things are more manageable.

The more I think about it, the more I like jettisoning the nose with the landing thrusters.  You can use all kinds of telemetry and remote sensing to verify the separation in situ, before firing the thrusters.  It's a dicey control problem to get it to launch cleanly, straight up, but it can be something that happens long before the crew departs Earth, ensuring that the MAV is in good condition before they commit.

[TheRadicalModerate]

But there are all kinds of things that require good mobility in the first days after landing.  The most critical are things relating to a stay / no-stay decision. 

I'm not sure Mars will work that way. Due to launch windows, abort back may not be an immediate option.  (Well, maybe with opposition class missions?) I think there may well be no decision, stay is "baked in".

You should have oppo-class return options from before the time that the Starship gets captured into Mars orbit, through at least a few weeks after they land.  If anything looks like it's not manageable for staying the full synod, I'd guess there will be an abort.  In fact, I'll bet there are multiple decision points:

1) Capture / no-capture:  If there's a problem with any systems that might prevent a safe capture or direct EDL, there's likely to be a free return or thruster-assisted flyby that results in a return.  Of course, the same problems would interfere with a successfull Earth capture or EDL, but it gives you 9-12 more months to work the problem, or design a rescue mission.

2) Land / no-land:  If you've captured successfully, but something's wrong with either your heat shield or your gimbaled engines, you can abort back to Earth, using the oppo-class orbit.  It's easy to rescue the crew from LEO or HEEO when they return.

3) Touchdown / no-touchdown:  Obviously, you can wind up with a situation where the available terrain isn't acceptable for landing, or something's hinky with your landing thrusters.  You can only abort if you have enough prop to get back to orbit, but this could be ensured by refueling from a depot in LMO.¹

4) Stay / no-stay:  Is your tilt angle acceptable?  How's the soil under the landing footings?  Does the elevator work?  How's your ECLSS performing?  Do you have an uncontrollable air leak?  Can you access all essential supplies that were pre-landed?  There are any number of reasons to abort a mission in the first hours, and even more in the first couple of weeks.

5) Finally, there's a decision to commit to the entire synod-long mission, waiting for a new conjunction class window.  That could be several weeks into the mission, before the oppo-class window closes.

Disclaimer:  I think full-up Mars colonization is ill-advised, and colonization directly from mission #1, with no Earth-return options, is full-blown bat guano crazy.  Elon has proven himself to be astonishingly bad at gauging the public response to his actions, so I doubt he has a very good model for how much trouble SpaceX would be in if they lost a Mars crew and it were shown after the fact that they hadn't done everything possible to design a mission that was as safe as possible.  I assume that cooler heads will prevail.

Some others on this forum obviously don't share my opinions.


__________
¹It's not clear if a Starship can land with that much prop.  If that's possible, you obviously don't need a MAV.

[Vultur]

You should have oppo-class return options from before the time that the Starship gets captured into Mars orbit, through at least a few weeks after they land.  If anything looks like it's not manageable for staying the full synod, I'd guess there will be an abort.  In fact, I'll bet there are multiple decision points:

Hmm, maybe. This doesn't look like the kind of architecture I'd expect, but then, you appear to be starting with very different assumptions than I would.

Disclaimer:  I think full-up Mars colonization is ill-advised, and colonization directly from mission #1, with no Earth-return options, is full-blown bat guano crazy. 

I don't entirely agree that it's that crazy, but even if you and I think it's crazy, if SpaceX wants to do it and has volunteers, I don't think your or my opinion of it makes it less likely.

so I doubt he has a very good model for how much trouble SpaceX would be in if they lost a Mars crew and it were shown after the fact that they hadn't done everything possible to design a mission that was as safe as possible. 

If it were an entirely private mission (no NASA astronauts) I don't see why they would be in any trouble they couldn't handle. Especially as a first mission's people wouldn't be 'paying passengers'. Presumably they'd have good lawyers, liability waivers, etc. People die climbing Everest etc. all the time and the tour companies aren't destroyed. OceanGate didn't really survive the Titan submersible disaster, but that's more because they didn't have another vehicle...


EDIT: fixed quote tags

[MickQ]

Why not make the whole nose section be the MAV ??

Eject the forward flaps and separate the nose horizontally from the rest of the ship either below the landing thrusters, if they can be used for ascent, or above if carrying a dedicated engine/engines.

[StraumliBlight]

Why not make the whole nose section be the MAV ??

Eject the forward flaps and separate the nose horizontally from the rest of the ship either below the landing thrusters, if they can be used for ascent, or above if carrying a dedicated engine/engines.

NTRS: A Crew and Logistics Lander for the Common Habitat Architecture [Mar 9, 2024]

The Starship Ascent Module, shown in Figure 1, provides accommodation for the crew during entry, descent, and landing while berthed within the Garage. It provides ascent, rendezvous, and docking in a separated flight mode. It can sustain the crew for up to fourteen days. The propulsion system, shown in Figure 2, is sized to reach Gateway in a lunar surface ascent and reach a 5-Sol orbit in a Mars surface ascent. The element has been roughly sized with a control mass of 10,000 kg dry mass and 40,000 kg wet mass.

A notional placeholder for main propulsion is two Aeon-1 LOX-Methane rockets, made by Relativity Space, which has performance in the desired ballpark. [6] Propellant is supplied by two liquid oxygen tanks and two liquid methane tanks. Reaction Control System (RCS) thrusters also use LOXMethane propellant. A 100-lbf LOX-Methane thruster has been developed by Aerojet [7] and serves as a placeholder.

These thrusters are configured in four quads of four thrusters each. Each quad includes small liquid oxygen and liquid methane tanks that are topped off by the main propulsion propellant tanks.

The power and thermal subsystems are not presently sized, but the initial assumption is that the ascent module utilizes deployable soliators and batteries. The soliator is a concept proposed by NASA engineers to merge the functionality of a solar array and a radiator panel, such that one side of the device contains solar cells and the other side is a radiative surface. The batteries would be mounted between the propellant tanks and the soliators would mount to the four vertical struts linking the RCS quads to the cabin, visible in Figure 1 and Figure 2.

The crew cabin includes three 40-inch by 40-inch square hatches, a zenith hatch, visible in Figure 4, a nadir hatch, visible in Figure 2, and a cabin-tunnel hatch, visible in Figure 3. A window lies at the center of each hatch. Five additional cabin windows provide crew visibility, two for the two pilots and three for the remaining six crew.

[Slarty1080]

Why not make the whole nose section be the MAV ??

Eject the forward flaps and separate the nose horizontally from the rest of the ship either below the landing thrusters, if they can be used for ascent, or above if carrying a dedicated engine/engines.

NTRS: A Crew and Logistics Lander for the Common Habitat Architecture [Mar 9, 2024]

The Starship Ascent Module, shown in Figure 1, provides accommodation for the crew during entry, descent, and landing while berthed within the Garage. It provides ascent, rendezvous, and docking in a separated flight mode. It can sustain the crew for up to fourteen days. The propulsion system, shown in Figure 2, is sized to reach Gateway in a lunar surface ascent and reach a 5-Sol orbit in a Mars surface ascent. The element has been roughly sized with a control mass of 10,000 kg dry mass and 40,000 kg wet mass.

A notional placeholder for main propulsion is two Aeon-1 LOX-Methane rockets, made by Relativity Space, which has performance in the desired ballpark. [6] Propellant is supplied by two liquid oxygen tanks and two liquid methane tanks. Reaction Control System (RCS) thrusters also use LOXMethane propellant. A 100-lbf LOX-Methane thruster has been developed by Aerojet [7] and serves as a placeholder.

These thrusters are configured in four quads of four thrusters each. Each quad includes small liquid oxygen and liquid methane tanks that are topped off by the main propulsion propellant tanks.

The power and thermal subsystems are not presently sized, but the initial assumption is that the ascent module utilizes deployable soliators and batteries. The soliator is a concept proposed by NASA engineers to merge the functionality of a solar array and a radiator panel, such that one side of the device contains solar cells and the other side is a radiative surface. The batteries would be mounted between the propellant tanks and the soliators would mount to the four vertical struts linking the RCS quads to the cabin, visible in Figure 1 and Figure 2.

The crew cabin includes three 40-inch by 40-inch square hatches, a zenith hatch, visible in Figure 4, a nadir hatch, visible in Figure 2, and a cabin-tunnel hatch, visible in Figure 3. A window lies at the center of each hatch. Five additional cabin windows provide crew visibility, two for the two pilots and three for the remaining six crew.

That is similar to what I was trying to describe for the MAV. Although strangely the flaps and the heat shield are shown for this Moon version (where they are not needed) but they would be needed in the Mars version. The whole area around the flaps is likely reinforced as the flaps will exert considerable aerodynamic forces through to the hull here. So just remove the top and have some blow out panels lower down.

Obviously the details would be very different for Mars as a more powerful rocket would be need to lift from Mars than from the Moon, although a reduced crew of 6 or even 4 would help. It is not entirely clear to me at first look how the crew get back into the Lunar ascent vehicle and how it all works. Figure 15 in particular which shows 4 levels of structure which don't look stable if stacked alone or a good use of space if left atop the Starship?

[TheRadicalModerate]

NTRS: A Crew and Logistics Lander for the Common Habitat Architecture [Mar 9, 2024]

That is similar to what I was trying to describe for the MAV. Although strangely the flaps and the heat shield are shown for this Moon version (where they are not needed) but they would be needed in the Mars version. The whole area around the flaps is likely reinforced as the flaps will exert considerable aerodynamic forces through to the hull here. So just remove the top and have some blow out panels lower down.

Obviously the details would be very different for Mars as a more powerful rocket would be need to lift from Mars than from the Moon, although a reduced crew of 6 or even 4 would help. It is not entirely clear to me at first look how the crew get back into the Lunar ascent vehicle and how it all works. Figure 15 in particular which shows 4 levels of structure which don't look stable if stacked alone or a good use of space if left atop the Starship?

If you look through the paper, they're assuming that the forward flaps are aft of the nose fairing.  They were moved forward and dorsally on v2; I don't know if that's changed in v3, to say nothing of v4.  I suspect there's not enough nose room to support the MAV doors they have in the paper.

It's possible to fold back / jettison the forward flaps, but it's certainly more complex.  The paper doesn't seem to consider the complexities of the splitting mechanism, which would likely require dealing with the load paths of the front flaps, and numerous straight lines through the TPS / crunch wrap / thermal blanket surrounding the nose.

However, by moving the MAV all the way into the nose, that likely serves as enough ballast to offset the lack of nose header tanks.  The Mars Starship would then need rear headers for both LCH4 and LOX, which currently don't exist.  They might be a problem in terms of shifting weight too far back, even with the MAV in the tip of the nose.

RISD and NASA make strange bedfellows.  I searched in vain for the section on hab color schemes.

[Slarty1080]

The pressurized elements of this modified Starship are discussed: Starship Ascent Module, Airlock, Transfer Tunnel, Pressurized Crew Transfer Module, and Logistics Modules. This appears to be all focused-on return stage, airlocks, transfers tubes and logistics. What about a proper crew section with a radiation shelter, common area and crew quarters. Why design something using such small diameter tubes when you will be landing in a vehicle that already has a 9m diameter?

Interesting the Rover is used to transfer the crew between vehicles in orbit (PRISM)?

“Pressurized crew transfer is a required capability for arriving and departing crews). They are probably right here.
So, a crewed lander for 8 and a MAV and all the required equipment for a long stay on Mars, on a single Starship. I don’t think that is a likely scenario.

Common lander for the Moon and Mars!
“The Common Habitat, with dimensions of 8.4 meters in diameter and 15.6 meters in length and a control mass of 90 metric tons, is the driving payload for this study.”
Presumably that stays in orbit?

“Starship was the lander selected in the trade study, but it was too small to physically accommodate the Common Habitat. Consequently, the barrel section of the payload volume was increased by 7.68 meters. This stretched Starship is used as the common dimensions for all Starship variants in the Common Habitat architecture. It is important to note that due to industry sensitivities, no commercial data was used in this study.”
Yees, but we can all imagine anything we want just to increase the payload volume by another ten metres why don’t you?

Fig 11 LOL
As for the rest too much already. Some interesting ideas but not going to happen.