totm dec 2023 Artemis Discussion Thread

[tater]

27 minutes ago, SunlitZelkova said:

But it would be dangerous to go straight to 90 day long stays on the Moon or longer. Even if there is equipment ready, the steps should be incremental.

The thermal environment is one issue, radiation another. For longer term stays, they need a lower hab, covered with regolith, Lower relative to Starship. Still, the rad environment is 50% of Gateway right off the bat, as they have a regolith shield the entire thickness of the Moon covering half the sky. The thermal environment is not any more difficult than gateway, just different—Gateway is in constant sun, but there's little reflection, lunar surface has both reflection and direct sunlight, but it gets conduction as a possible control modality (or radiators in a shadowed area). Lunar habitation has been worked on by the civil engineering guys for many decades. Longer term stays are not really that difficult.

Yeah, there are unknowns, the way to find them is to put people there for longer stays. Not send 2 people for 2 weeks every year or two. The way to do it is to just do it.

[SunlitZelkova]

2 hours ago, tater said:

Yeah, there are unknowns, the way to find them is to put people there for longer stays. Not send 2 people for 2 weeks every year or two. The way to do it is to just do it.

I think (and hope) that part of the rational for once a year missions (besides the elephant in the room that is SLS development) is to give leeway for rescheduling them if the first one goes well.

So if the first two week mission goes well in 2028, the next one can be reconfigured for 20-25 days, and then if that goes well in 2030 we have a month long stay on the Moon, followed by regular long duration stays with the surface habitat (whether that be another LSS or something else). Artemis III is 6.5 days, so we can already see “doubling” in Artemis V.

Sending a pressurized rover in 2029 when the LTV should already be there feels quite fishy.

[tater]

44 minutes ago, SunlitZelkova said:

I think (and hope) that part of the rational for once a year missions (besides the elephant in the room that is SLS development) is to give leeway for rescheduling them if the first one goes well.

There is no leeway.

SLS/Orion has ZERO schedule margin at this point. Later missions—and honestly all crew missions for safety reasons—should have EUS... which does not even exist yet.

On top of that, the only useful mission is landing people on the Moon. NRHO is a pointless place to put people. You can make an argument for a halo orbit for a facility, prop depot, etc, but there is zero reason to put people there except to move them to the surface. All that NRHO<—>surface transit is done by not SLS/Orion.

If Lunar Starship works, then SLS/Orion are no longer needed. Load crew in LEO via some tested system (Dragon, etc), take them RT back to LEO, EDL on Earth whatever way is safe and available.

 

[RCgothic]

Also, without SLS/Orion swallowing such a large chunk of the budget, there would be enough money to spend on things like extra missions and surface habs.

Congress won't give that same budget to anything other than SLS/Orion. That's the part of the problem that needs to change. Because this schedule is pitiful.

[SunlitZelkova]

5 hours ago, tater said:

There is no leeway.

What I meant was changing the flight plan for the lunar surface stay. This should be pretty easy to do.

The launch and landing dates will remain the same no matter what due to the way SLS development is, as you mention.

6 hours ago, tater said:

On top of that, the only useful mission is landing people on the Moon. NRHO is a pointless place to put people. You can make an argument for a halo orbit for a facility, prop depot, etc, but there is zero reason to put people there except to move them to the surface. All that NRHO<—>surface transit is done by not SLS/Orion.

It’s surprising that they don’t consider a four person landing crew given that the lesser landers are out.

[RCgothic]

But if they don't have someone staying at the gateway what is the point of the gateway /s

[tater]

4 hours ago, SunlitZelkova said:

What I meant was changing the flight plan for the lunar surface stay. This should be pretty easy to do.

The launch and landing dates will remain the same no matter what due to the way SLS development is, as you mention.

Once they get to Gateway they can get to the surface every 6.5 days or so. A benefit of NRHO is apparently a broad range of transfer windows.

 

4 hours ago, SunlitZelkova said:

It’s surprising that they don’t consider a four person landing crew given that the lesser landers are out.

Yeah, seems like any alternate lander needs to be cheaper, or better.

[wumpus]

On 3/29/2022 at 1:21 PM, Beccab said:

That was about the "power" part, which is definitely and extensively covered by HLS. For the thermal part it wouldn't be hard to go the Shuttle way, i.e. foldable (and retractable) radiators Space Tug style
 

You shouldn't need that, I'm fairly sure the ISS has less area of solar panels than radiators.  Running thermal lines around starship might not be fun, but probably easier then making a fold-out scheme like that.

[tater]

Quote

"Starship can land 100 tons on the lunar surface," said Aarti Matthews, Starship Human Landing System program manager for SpaceX. "And it’s really hard to think about what that means in a tangible way. One hundred tons is four fire trucks. It’s 100 Moon rovers. My favorite way to explain this to my kids is that it's the weight of more than 11 elephants."

 

Quote

"We all need to be thinking bigger and better and really inspirationally about what we can do," Matthews said. "Anyone who has worked on hardware design for space application knows you’re fighting for kilograms, and sometimes you’re fighting for grams, and that takes up so much time and energy. It really limits ultimately what your system can do. That’s gone away entirely."

 

Quote

With her comments last week Matthews extended that challenge to Michel and other engineers and scientists at the space agency.

"If you, as an engineer, are developing an in-situ resource utilization system, what does your system look like when you have no mass constraint?" she asked. "What about when you have no volume constraint? That would be the exciting thing that I would like to hear from NASA engineers, what they can do with this capability."

 

[SunlitZelkova]

Uh… what about the money constraint?

Are things really only small because of mass constraints?

Or does NASA not actually do any sort of cost reduction measures in the first place?

[sevenperforce]

36 minutes ago, SunlitZelkova said:

Uh… what about the money constraint?

Are things really only small because of mass constraints?

Or does NASA not actually do any sort of cost reduction measures in the first place?

Well, the primary constraints are mass and volume; remove those, and you've got a lot of room to work. Especially because miniaturizing things costs more money too.

[tater]

48 minutes ago, SunlitZelkova said:

Uh… what about the money constraint?

Are things really only small because of mass constraints?

Or does NASA not actually do any sort of cost reduction measures in the first place?

Making things small/light makes them more, not less expensive.

17 minutes ago, sevenperforce said:

Well, the primary constraints are mass and volume; remove those, and you've got a lot of room to work. Especially because miniaturizing things costs more money too.

Also, say they get one chance to land a specific experiment. It's small, make super light and small. And it MUST work, or you might not get another chance for years.

Make it slightly bigger, a lot cheaper—and send a few, just in case.

[Silavite]

22 minutes ago, tater said:

Make it slightly bigger, a lot cheaper—and send a few, just in case.

That said, the, "send a few," part of this has been done before. Viking 1/2, Pioneer 10/11, Voyager 1/2, Spirit/Opportunity were all probes which were launched in pairs. Going beyond 2 would increase margins, however.

Edited May 2, 2022 by Silavite

[tater]

1 minute ago, Silavite said:

That said, the, "send a few," part of this has been done before. Viking 1/2, Pioneer 10/11, Voyager 1/2, Spirit/Opportunity were all probes which were launched in pairs. Going beyond 2 would increase margins, however.

Yeah, but those were still expensive. We're talking about gear placed on the ground by humans in this case.

[Codraroll]

4 minutes ago, tater said:

Making things small/light makes them more, not less expensive.

This close to midnight (on the side where the distance keeps increasing), I forget where I heard it, but Starship can really be a game changer for Moon exploration.

Mass constraints and a very high launch cost makes the space programs go to greath lengths to shave off a little bit of mass. It means custom-machined titanium parts, assembled by hand, to the tune of several tens of thousands of dollars, if it makes the equipment a few hundred grams lighter. All worth it because you only get to launch so many kilograms, at such a high cost, which means you get to do more stuff if you can fit more parts within the mass limit. And the high launch cost means that optimizing your equipment to do two things will almost always be cheaper than sending two different sets of equipment.

But if Starship lets you launch a few tons to the moon in one go, for a comparably low price, then suddenly it makes less sense to spend a fortune on the hardware. No need to make a Moon excavator from scratch using custom-machined titanium parts, just modify some Caterpillar equipment off the shelf. If it doesn't work, buy another (cheap) and send it up (also cheap). Well, cheaper than doing it all from scratch yourself. Best thing is, Caterpillar itself might be capable of building it for you.

Several terrestrial machine manufacturers already make equipment rated for extremely harsh conditions. Bores for deep-underground mines at boiling temperatures, rovers that inspect pools of corrosive chemicals, devices that poke into nuclear storage sites to collect practically-glowing debris, swimming robots that traverse thermal vents on the seafloor, extinguisher robots that crawl into hydrocarbon fires, injection pumps for oil wells rated to push soap into porous rock underneath a kilometer of salt water ... The Moon may be a harsh mistress, but there are some fiendishly tough environments on Earth as well, and we build equipment that work just fine in them. Building for the Moon wouldn't be an insurmountable challenge, if mass isn't a concern.

The problem with space equipment at the moment is that payloads are built to match the limitations of the launch vehicles, and they have to be optimized around those limitations to give the greatest bang for the (considerable) buck it takes to buy a launch. But make it all cheaper, and suddenly the limits for what can be a payload changes dramatically. That makes payload manufacturing a lot more accessible, and it opens up space for a host of new ventures.

[sevenperforce]

Once you’re in orbit, you’re halfway to anywhere.

Earth’s gravity well gives us a delightful atmosphere that supplies us with delicious oxygen and protects us from all manner of outer-space harm and makes sunsets pretty, but both the gravity and that atmosphere make it just tremendously difficult to get into space. So the barrier to exploration is rather high. Space missions are a little like climbing Pike’s Peak: it’s not THAT hard, but if it you don’t have a way to make it to the foot of the trail, you’re certainly not making it to the top. 

But once you have low-cost access to LEO, everything else becomes much, much easier.

 

[SunlitZelkova]

4 hours ago, Codraroll said:

But if Starship lets you launch a few tons to the moon in one go, for a comparably low price, then suddenly it makes less sense to spend a fortune on the hardware. No need to make a Moon excavator from scratch using custom-machined titanium parts, just modify some Caterpillar equipment off the shelf. If it doesn't work, buy another (cheap) and send it up (also cheap). Well, cheaper than doing it all from scratch yourself. Best thing is, Caterpillar itself might be capable of building it for you.

Sort of reminds me of how Toyota will be making the pressurized lunar rover for Artemis, in all likelihood to be launched by Starship HLS.

Building a purpose built transport lander and launching it on an expensive expendable rocket wouldn’t make sense unless it was Japanese, but I think (guess) H3 Heavy does not have the payload to do that, and it won’t debut until the 2030s anyways. The rover is supposed to land in 2028 or 2029.

Also, something I just thought of is that it would be rather unfortunate to have the rover ready but the mission delayed because of SLS.

[tater]

 

[tater]

 

[wumpus]

Bill Nelson may well publicly state that "cost plus is a plague on us", but that won't stop senators from making sure NASA maximizes the pork on pork-heavy spending bills.  It might help try to eliminate any cost-plus contracts in the budget they send to the White House (who may have friends to add some in) and in turn sends the combined federal budget to the House.  But nothing stops the congress from funding the projects as "cost plus".

This has been your US specific civics lesson for today.

[Beccab]

6 minutes ago, wumpus said:

Bill Nelson may well publicly state that "cost plus is a plague on us", but that won't stop senators from making sure NASA maximizes the pork on pork-heavy spending bills.  It might help try to eliminate any cost-plus contracts in the budget they send to the White House (who may have friends to add some in) and in turn sends the combined federal budget to the House.  But nothing stops the congress from funding the projects as "cost plus".

This has been your US specific civics lesson for today.

Yup, but with Ballast having at least some control on congress and Shelby retiring this year there's room for at least some change. It probably won't be a lot, but at least I doubt it will get worse

[tater]

 

Some details on actual launch windows for Artemis I. Looks like 3 days every 2 week window are actually available for SLS. Starship OTF? <shrug> No good idea on a date.

[tater]

This is way down the line for the "sustainable" base with ISRU, but interesting:

https://www.sciencedirect.com/science/article/pii/S0094576522001965

Dust mitigation.

[tater]

 

[Beccab]

God, yes please