totm dec 2023 Artemis Discussion Thread

[tater]

On 4/28/2024 at 5:30 AM, AckSed said:

If in the future something does go wrong, I have a polite request for the few people reading this: don't go mad. Do not argue yourself into the hole that all exploration should be done robotically. That you knew this would happen and humans should never have left the ground, never mind Earth.

Human spaceflight is not about "science," it's about exploration and more. Robots were more cost effective decades ago, and gain capability now at an insane rate. If it was about getting "science" in the KSP sense, we have no need of humans—but it's just not the same as seeing people doing it.

[Exoscientist]

 

Dave Masten of Masten Space Systems in a SpaceVidcast video discussed adapting a Centaur upper stage to serve as a lunar lander. In the video he estimates it to cost in the range of only $50 million(!)

The discussion on the lunar lander takes place about 15 minutes into the one hour video. Masten also mentions this modified Centaur could transport 6 metric tons between a Lagrange point, L1 or L2, and the lunar surface. Such a lander could also be used between low lunar orbit and the lunar surface, as for a manned mission from Earth.

If true, then it is unconscionable that NASA claims a return to the Moon can’t be done because a lander would cost ca. $10 billion, when it can actually be done two orders of magnitude more cheaply than that. In any case NASA needs to do a study to see if this conversion of a Centaur to a lander can actually be done so cheaply.

  Bob Clark

 

Edit: that is that’s what NASA was saying back in 2012 when Masten made this video. Remember that statement made by former NASA administrator Charles Bolden that, “We won’t return to the Moon in my lifetime.”

Edited May 6 by Exoscientist
Added context.

[StrandedonEarth]

Isn't Centaur a balloon tank of hydrogen? No pressure, no strength; not an issue until the hydrogen boils off. Oh yeah, oops. Add on all the other systems to make it work. You want people on it? That thin skin will need MMOD protection, at least that could double as insulation. It also sounds like a one-way trip, and it has to get to lunar space first!

I don't see a Centaur-based lander working very easily (of course it can work, by applying sufficient funding). SLS is what we got trying to re-use Shuttle hardware, remember?

[tater]

26 minutes ago, StrandedonEarth said:

Isn't Centaur a balloon tank of hydrogen? No pressure, no strength; not an issue until the hydrogen boils off. Oh yeah, oops. Add on all the other systems to make it work. You want people on it? That thin skin will need MMOD protection, at least that could double as insulation. It also sounds like a one-way trip, and it has to get to lunar space first!

I don't see a Centaur-based lander working very easily (of course it can work, by applying sufficient funding). SLS is what we got trying to re-use Shuttle hardware, remember?

ACES was a decent concept (XEUS lander), but yeah, it also has issues. Even discussing alternate Artemis vehicles at this point is comical. Some new thing that involves ULA, Boeing, LockMart, et al, means adding 15 years? Meanwhile the program eats its $2B/yeah regardless? It's a decent program because it has support, but in the end it is making lemonade out of the lemon which is SLS/Orion.

[Exoscientist]

13 hours ago, tater said:

ACES was a decent concept (XEUS lander), but yeah, it also has issues. Even discussing alternate Artemis vehicles at this point is comical. Some new thing that involves ULA, Boeing, LockMart, et al, means adding 15 years? Meanwhile the program eats its $2B/yeah regardless? It's a decent program because it has support, but in the end it is making lemonade out of the lemon which is SLS/Orion.

I agree with you contracting Boeing or Lockheed to do it they would figure out a way to charge NASA a billion+ dollars for it. (See my sig file.) But I think Masten was thinking of using the stage and modifying it by his company to do it, at the millions of dollars range instead of billions of dollars range.

 The key point is getting a company to develop the lander privately funded. That is how SpaceX was able to effect development cost cuts in the range of 90%(!) off the usual government funded  costs on the Falcon 9.

  Bob Clark

Edited May 7 by Exoscientist

[Codraroll]

4 hours ago, Exoscientist said:

I agree with you contracting Boeing or Lockheed to do it they would figure out a way to charge NASA a billion+ dollars for it. (See my sig file.) But I think Masten was thinking of using the stage and modifying it by his company to do it, at the millions of dollars range instead of billions of dollars range.

It is oh-so-easy to stand with a PowerPoint presentation and promise a million-dollar range instead of a billion-dollar range. But once integration begins, those order-of-magnitude savings have a nasty tendency to evaporate into *less than nothing*.

[magnemoe]

21 hours ago, tater said:

Human spaceflight is not about "science," it's about exploration and more. Robots were more cost effective decades ago, and gain capability now at an insane rate. If it was about getting "science" in the KSP sense, we have no need of humans—but it's just not the same as seeing people doing it.

Except its plenty of stuff its very hard to make robots to do. Why has nobody made an remote operated EVA robot? Astronauts are clumsy in the suits anyway. 
To take images or point an laser at rocks, sure robots are much cheaper. Drill 20 meter down on the moon and collect core samples? at multiple locations  

[magnemoe]

17 hours ago, StrandedonEarth said:

Isn't Centaur a balloon tank of hydrogen? No pressure, no strength; not an issue until the hydrogen boils off. Oh yeah, oops. Add on all the other systems to make it work. You want people on it? That thin skin will need MMOD protection, at least that could double as insulation. It also sounds like a one-way trip, and it has to get to lunar space first!

I don't see a Centaur-based lander working very easily (of course it can work, by applying sufficient funding). SLS is what we got trying to re-use Shuttle hardware, remember?

Use the centaur as an crasher stage, land with the accent stage, leaving behind the landing legs and other landing equipment is needed or have and docking system for an partial reusable lander, you need to refuel and restock it. 

As for the Starship lander, why does the top looks like an Starship? Why not just use an fairing drop it and expand stuff like the lift and landing engines in LEO? And its too large for an 4 man crew? Make it lightweight, and 2-3 decks+ cargo bay. 
Even this is lavish, dual air locks, cleaning zones, an workshop, and multiple labs, individual cabins. Bathroom with an shower, it should work well at moon gravity. 
Later replace it with an more capable one, keep the other around the moon as an gateway station and an fuel depot and as an rescue craft if lander 2 can not reach orbit. 

[darthgently]

1 hour ago, magnemoe said:

Except its plenty of stuff its very hard to make robots to do.

I challenge a humanoid robot to untangle a frozen tangled 100' extension cord in a blizzard. 

Of course a good robot would have stowed the cord properly in the first place.  Wait.  On second thought, I want to see a humanoid robot that can properly coil an extension cord under adverse conditions.   Killer app for labor robots right there

 

Edited May 7 by darthgently

[RCgothic]

The secret about starship being oversized for Artemis is that Artemis is a customer but Starship has grander ambitions.

[darthgently]

10 minutes ago, RCgothic said:

The secret about starship being oversized for Artemis is that Artemis is a customer but Starship has grander ambitions.

Another angle: Starship is a base, not a lander

[tater]

2 hours ago, magnemoe said:

Except its plenty of stuff its very hard to make robots to do. Why has nobody made an remote operated EVA robot? Astronauts are clumsy in the suits anyway. 
To take images or point an laser at rocks, sure robots are much cheaper. Drill 20 meter down on the moon and collect core samples? at multiple locations  

Teleoperation suffers from the problems that Mars rovers face, heck, even lunar - Earth teleoperation has lag issues. I think vehicles with autonomy—give them a mission, and even ideal places to look, and the robot goes there itself, and can even notice potentially interesting finds autonomously. This could likely be done now. Having people do cool stufff when they are there is great, and they will get a ton done, fast—but it's not about what generates more knowledge per unit time, I was talking about cost efficiency. The logistical overhead of human crew is huge (and hence cost).

[AckSed]

8 hours ago, darthgently said:

Another angle: Starship is a base, not a lander.

I suspect the extra added payload (and space) was a selling-point, as Starship's payload bay will actually allow you to lift a bungalow (estimated at 125 metric tons), and have space for a small UK 2-storey house, roof and all - I measured.

That's enough space for a nuclear reactor, a ridiculous load of solar, an inflatable habitat and a vacuum-capable backhoe to shove dirt over it... and still have enough space for individual astronauts.

Starship is its own prefab housing for Moon builders.

Edited May 8 by AckSed

[Exoscientist]

                                                        The right size for an Artemis lander(the one on the right.)
                                                                  (Image credit Ken Kirtland.)

 

              Bob Clark

[Ultimate Steve]

2 hours ago, Exoscientist said:

The right size for an Artemis lander(the one on the right)

You keep saying that Artemis should not be "Apollo on steroids" and that the focus should be on a very small lander that can fit on SLS comanifested with Orion to enable single launch Lunar missions, or something that can fit on small commercial launch vehicles. Beyond simplified logistics and not needing to develop refueling technologies, I can't think of any large reasons why you would want to make the tremendous sacrifices needed to get a lander that small. Please let me know what reasoning you have for this. I have come away with the opposite impression, that NASA does not want another Apollo, they want something more capable and comfortable than this thing:

Granted, designing SLS to be big enough and Orion to be capable enough to support a more capable lander in the first place is a thing that would have been great. In the Apollo days they had the freedom to plan like that, but these days, not really.

Here's just a short list of the things we know NASA would prefer the Artemis lander to be able to do that Apollo didn't do:

• Carry four people. This obviously increases volume requirements and therefore structural mass requirements, means you need to take 2 more space suit, and means you need to carry twice as much life support.
• NRHO. I know you like to try to find ways around this by redesigning the Orion ESM and SLS second stage, but the lander starting from NRHO is pretty much non negotiable at this point.
• Stay on the surface for a week. Or more than a week, eventually. The longest Apollo landings were only 3 days, and we can assume that they will want to be able to hang out for at least one Gateway orbital period in case their burns don't go quite right and they need to try a second time. Gateway takes 7 days to orbit, we're looking at 2 weeks, at least 4x longer than Apollo. This means 4x as much life support - 8x accounting for the increased crew size. This also means more batteries on a battery based architecture, or a switch to solar (or fuel cells). That's more mass. If the duration gets long enough, you want provisions for various forms of hygiene.
• Airlock. Not having to depressurize the spacecraft for every EVA and having some provision for having the moon dust not getting everywhere (including the astronauts' lungs). There are many different levels of this you can have, but in any case it means more volume and more mass.
• Bathroom. Even if it's just what they have on Orion or Dragon, a small box with a curtain, that's still mass.
• Better sleeping arrangements. This is more minor, but to be productive on the Moon you want to sleep well. Being hammocked in like Tetris pieces, almost nose to rear, is not conducive to good sleep. While something like the ISS compartments is ideal, you probably won't get that even on a heavier lander, but just about anything is better than what they did on Apollo.
• More downmass. They'd love to have more experiments to run.
• More upmass. Apollo 17 managed to grab ~110kg of rocks over 3 days with 2 people. While it won't be a linear relationship, at a certain point you've got to pick and choose your samples, it stands to reason 4 people over a week are going to be able to collect more samples, and more samples is better.

And things they want to pay attention to in the long term:

• Reuse. Landers would be designed with refueling ports, with materials that wouldn't wear out as quickly, with more solar than necessary because solar does wear out, non single use landing gear if single staged, more docking ports if two staged, and with micrometeoroid protection. There would also be a pressure towards single staged vehicles (Or, I guess, that weird 3 stage concept, which has its own drawbacks), which means you have only one go at the rocket equation, which means more mass.
• ISRU. This is waaayyy out there but there is a very slight preference for propellants that are producible on the Moon. Hydrogen and Oxygen would in theory allow for less mass due to higher isp, but then you have to add mass for boiloff prevention, add a ton of volume if it is hydrogen because of its density, and probably make your RCS a little bit more complicated.
• Evolvable into something that can deliver a Moon base. You can't deliver a 10 ton base module if you are limited to 15 tons total.

This is Apollo on steroids. A light version of this might not need to be on quite as many steroids as Altair was, but the pressures listed above certainly push it closer to Altair than the LEM. 15 tons for something that can even do some of the above is a lot to ask.

And another thing, Orion/Gateway are going to be operating at a higher pressure than Apollo - 62kpa is the lowest number I've seen, Apollo used 34kpa. For HLS to be compatible, it has to be able to hold at least that much pressure. A bit more structural mass and a very small amount of additional gas mass is required.

Edited May 8 by Ultimate Steve

[tater]

2 hours ago, Ultimate Steve said:

You keep saying that Artemis should not be "Apollo on steroids" and that the focus should be on a very small lander that can fit on SLS comanifested with Orion to enable single launch Lunar missions, or something that can fit on small commercial launch vehicles. Beyond simplified logistics and not needing to develop refueling technologies, I can't think of any large reasons why you would want to make the tremendous sacrifices needed to get a lander that small.

As you so thoroughly explain after this, the actual requirements completely disallow such a small lander. It MUST be able to deal with aborts that can then phase with Gateway/NRHO, so a crew duration of weeks. This ignores the fact that SLS/Orion is a garbage stack for this use case, and will never be able to comanifest a lander. If a single stack launch was desired for SLS, we first need to invent a time machine, and spec SLS to be useful for this. Smaller Orion? When was Orion first started, 20 years ago? Either our time machine deals with that (Shelby has an "accident" via time machine?), or tag on another 20 years.

Artemis exists as a program because Bridenstine was put in place with a lousy, expensive vehicle that exists to move dollars to districts, and came up with something actually useful for it to do. Was the useful thing landing humans on the Moon? NO. That is not the point of Artemis. The point of Artemis is to get "new space" to build cislunar stuff using the COTS/CCV mechanism.

Just as the point of SLS/Orion was to throw money at old Shuttle contractors and NASA centers, the point of Artemis is to throw money at "new space"—albeit much less money than SLS/Orion (pushing what, $50B now?)—to have in house capability in the future that allows for actual usefulness.

3 hours ago, Ultimate Steve said:

Airlock. Not having to depressurize the spacecraft for every EVA and having some provision for having the moon dust not getting everywhere (including the astronauts' lungs). There are many different levels of this you can have, but in any case it means more volume and more mass.

Excellent point, and also the new suit size is large, so more volume to store those. Gotta wonder about the bearings on the rotating parts and dust, too. More volume really helps here.

[Ultimate Steve]

23 minutes ago, tater said:

the actual requirements

Do you happen to have a document with the actual requirements somewhere? I looked briefly and couldn't find it.

[tater]

Initial talks about what a Gateway lander might look like (Gerst presented this):

36t min. 43t max.

Doesn't list requirements, just min masses for components tells us something. The Ascent Element is at min 2X the mass of the Apollo LM, nearly 3X at max.

Here, scroll down to Attachment F (a zip)

https://sam.gov/opp/d5460a204ab23cc0035c088dcc580d17/view

 

Bullet points (for initial landing, higher requirements for all landings beyond that—reuse, 4 crew vs 2, etc):
 

Quote

 

HLS-R-0318 HLS Operations Mass Delivery from Lunar Orbit - Initial
The HLS shall deliver 865 kg (threshold) and 965 kg (goal) from Lunar Orbit to the lunar

surface in accordance with the Departure Mass and Volume Allocation Table 8.

Rationale: The 865 kg is based on delivery of two crew, and government furnished equipment for high-level surface operations, but surface mission refinements will set final value.

 

 

Quote

HLS-R-0319 HLS Operations Mass Delivery Return to Lunar Orbit - Initial
The HLS shall return at least 525 kg from the lunar surface to Lunar Orbit in accordance

with the Ascent Mass and Volume Allocation Table 9.

Rationale: Required mass to be carried based on return of two crew, and government furnished equipment for current, high-level surface operations approach but surface mission refinements will set final value. 500kg assumes the xPLSS is discarded before ascent. It is an agency preference that the xPLSS be returned if possible. Assume an xPLSS return mass budget of 205kg for a total ascent mass of 705 kg. This mass reflects return after a nominal surface mission.

 

Quote

HLS-R-0324 HLS Habitation Capability - Initial

The initial HLS shall provide a habitable environment for two crew for an 8 earth day lunar sortie without pre-emplaced surface infrastructure.

Rationale: In the initial architecture, no pre-emplaced surface assets will be available at the landing site. The HLS will provide all habitability functionality throughout the sortie. This will drive consumables requirements, as well.

 

Quote

HLS-R-0058 Abort to Crewed Staging Vehicle (CSV)
The HLS shall be capable of conducting a safe return and dock to the crewed staging

vehicle within lunar orbit in the event of an abort.

Rationale: The agency requires crewed vehicles to have the capability to abort to a safer location. For the case of a lunar sortie mission, the requirement is for the crewed vehicle to be able to return to lunar orbit for rendezvous and dock. Astrodynamic considerations may dictate that the HLS provide a “shelter in place” capability until the next available launch window presents itself. For the purpose of this requirement abort is defined as : Abort: Same as Mission Abort. The forced early return of the crew to the crewed staging vehicle when failures or the existence of uncontrolled catastrophic hazards prevent continuation of the mission profile and a return to the crewed staging vehicle is required for crew survival.

! Next launch window for what ? SLS, lol?

 

[RCgothic]

I'm never going to get on board with paring back Artemis.

I want permanent off-world habitation. Single-stack SLS missions are never going to achieve that. 

[tater]

3 minutes ago, RCgothic said:

I'm never going to get on board with paring back Artemis.

I want permanent off-world habitation. Single-stack SLS missions are never going to achieve that. 

Luckily for you, single stack SLS missions to accomplish literally anything useful are not possible, and can never be possible!

[RCgothic]

True. But say (impossibly) they were. Then what? What does that SLS-Orion-Apollo do next? What are its stretch goals, what can it achieve? Maybe 12t of down mass every other year, disregarding crew missions? Can't achieve anything lasting that way. It'll get rapidly cancelled after its flag and footprints.

The HLS landers are the genuinely useful bits of Artemis. Suddenly the downmass is hundreds of tonnes, multiple times a year.

Habs. Labs. Construction equipment. Solar collectors. ISRU. Refuelling stations. Giant surface telescopes. Permanent off-world inhabitation for dozens to hundreds of individuals. Enabling technologies for Beyond Earth/Moon exploration!

And the development costs to enable those sorts of plans are essentially peanuts in spaceflight terms.

"It's too hard!"

Not as hard as closing SLS's 20 tonne mass budget deficit I'd wager.

"It'll be delayed!"

Not as delayed as any alternative program would be.

"It's a waste of money!"

 This can't possibly be serious.

Edited May 8 by RCgothic

[tater]

40 minutes ago, RCgothic said:

The HLS landers are the genuinely useful bits of Artemis. Suddenly the downmass is hundreds of tonnes, multiple times a year.

This. Minus huge landed mass on the lunar surface, going back at all is pointless and stupid. Flags and footprints—been there, done that. A real base, or stay home.

[magnemoe]

6 hours ago, Ultimate Steve said:

You keep saying that Artemis should not be "Apollo on steroids" and that the focus should be on a very small lander that can fit on SLS comanifested with Orion to enable single launch Lunar missions, or something that can fit on small commercial launch vehicles. Beyond simplified logistics and not needing to develop refueling technologies, I can't think of any large reasons why you would want to make the tremendous sacrifices needed to get a lander that small. Please let me know what reasoning you have for this. I have come away with the opposite impression, that NASA does not want another Apollo, they want something more capable and comfortable than this thing:

Granted, designing SLS to be big enough and Orion to be capable enough to support a more capable lander in the first place is a thing that would have been great. In the Apollo days they had the freedom to plan like that, but these days, not really.

Here's just a short list of the things we know NASA would prefer the Artemis lander to be able to do that Apollo didn't do:

• Carry four people. This obviously increases volume requirements and therefore structural mass requirements, means you need to take 2 more space suit, and means you need to carry twice as much life support.
• NRHO. I know you like to try to find ways around this by redesigning the Orion ESM and SLS second stage, but the lander starting from NRHO is pretty much non negotiable at this point.
• Stay on the surface for a week. Or more than a week, eventually. The longest Apollo landings were only 3 days, and we can assume that they will want to be able to hang out for at least one Gateway orbital period in case their burns don't go quite right and they need to try a second time. Gateway takes 7 days to orbit, we're looking at 2 weeks, at least 4x longer than Apollo. This means 4x as much life support - 8x accounting for the increased crew size. This also means more batteries on a battery based architecture, or a switch to solar (or fuel cells). That's more mass. If the duration gets long enough, you want provisions for various forms of hygiene.
• Airlock. Not having to depressurize the spacecraft for every EVA and having some provision for having the moon dust not getting everywhere (including the astronauts' lungs). There are many different levels of this you can have, but in any case it means more volume and more mass.
• Bathroom. Even if it's just what they have on Orion or Dragon, a small box with a curtain, that's still mass.
• Better sleeping arrangements. This is more minor, but to be productive on the Moon you want to sleep well. Being hammocked in like Tetris pieces, almost nose to rear, is not conducive to good sleep. While something like the ISS compartments is ideal, you probably won't get that even on a heavier lander, but just about anything is better than what they did on Apollo.
• More downmass. They'd love to have more experiments to run.
• More upmass. Apollo 17 managed to grab ~110kg of rocks over 3 days with 2 people. While it won't be a linear relationship, at a certain point you've got to pick and choose your samples, it stands to reason 4 people over a week are going to be able to collect more samples, and more samples is better.

And things they want to pay attention to in the long term:

• Reuse. Landers would be designed with refueling ports, with materials that wouldn't wear out as quickly, with more solar than necessary because solar does wear out, non single use landing gear if single staged, more docking ports if two staged, and with micrometeoroid protection. There would also be a pressure towards single staged vehicles (Or, I guess, that weird 3 stage concept, which has its own drawbacks), which means you have only one go at the rocket equation, which means more mass.
• ISRU. This is waaayyy out there but there is a very slight preference for propellants that are producible on the Moon. Hydrogen and Oxygen would in theory allow for less mass due to higher isp, but then you have to add mass for boiloff prevention, add a ton of volume if it is hydrogen because of its density, and probably make your RCS a little bit more complicated.
• Evolvable into something that can deliver a Moon base. You can't deliver a 10 ton base module if you are limited to 15 tons total.

This is Apollo on steroids. A light version of this might not need to be on quite as many steroids as Altair was, but the pressures listed above certainly push it closer to Altair than the LEM. 15 tons for something that can even do some of the above is a lot to ask.

And another thing, Orion/Gateway are going to be operating at a higher pressure than Apollo - 62kpa is the lowest number I've seen, Apollo used 34kpa. For HLS to be compatible, it has to be able to hold at least that much pressure. A bit more structural mass and a very small amount of additional gas mass is required.

I totally agree, had another post above that Moonship was oversize for the initial landings. Now I would use another Moonship with an orbital module for the orbital moon station, it would be an fuel depot and even an rescue ship.
But the BO lander is probably more practical but might likely more expensive / slower, SpaceX is testing Starship. Yes New Glen is less ambitions but its not SS more like falcon heavy as I understand. 
So you use your 18 wheel truck to buy an burger as its cheaper / faster than other options like taxi or meal delivery services.  
You obviously want SS for the base, they should also be pretty easy to turn into base modules. Then the talk ISRU and hydrolox become more relevant again. 
 

[RCgothic]

I also suspect one of the reasons Delta Cryogenic Second Stage was chosen over Centaur for the basis for ICPS and EUS was the separate tanks make an explosion due to propellant mixing less likely. A lander based on Centaur would go against this philosophy. 

(So does Starliner on Atlas/Vulcan, but that's not a NASA designed vehicle).

[tater]

52 minutes ago, RCgothic said:

I also suspect one of the reasons Delta Cryogenic Second Stage was chosen over Centaur for the basis for ICPS and EUS was the separate tanks make an explosion due to propellant mixing less likely. A lander based on Centaur would go against this philosophy. 

ICPS shows being built by Boeing and ULA, while Centaur shows just ULA.

Centaur is already crew rated, and is unambiguously a better stage than ICPS/EUS I think—it's arguably one of the best rocket stages ever built. I think the issue with a Centaur based lander (XEUS) was refilling the tank (per Shelby a no no), and obviating SLS (also Shelby).