NASA Human Landing System

[DDE]

7 hours ago, tater said:

My idea would be:

Your idea is bad because it doesn’t account for the 2024/2028 administration reverting to another Journey to Mars and requiring the LOP-G to become a staging ground for what used to be the DST. A Moon base would be less useful in that role, especially given how lunar ISRU isn't in the picture of most NASA DRAs.

I think everyone in this thread has forgotten the context of the DSG proposal from a few years back: it was a compromise solution designed to adapt to differing requirements from differing administrations (while not properly committing to either goal).

Never, never, never ever leave politics out of the picture.

Edited February 17, 2019 by DDE

[sevenperforce]

What kind of engines exist and are appropriate at this time?

 

It makes no sense whatsoever to use an entire CPL logistics supply launch just to refuel the transfer element when you can simply re-launch a brand new transfer element.

[wumpus]

8 hours ago, DDE said:

Never, never, never ever leave politics out of the picture.

No bucks, no Buck Rogers.  And with the exception of Blue Origin and the self-funding parts of SpaceX (not necessarily the Mars dream) the bucks require politics.

[sevenperforce]

If the crew/ascent vehicle is small, then it is basically a space taxi between LOP-G (or wherever) and the lunar surface, and you need existing infrastructure on the surface to support exploration and science activity. Suitable for a flags-and-footprints mission as a proof-of-concept and for regular exploration missions once the infrastructure is in place.

I advanced a wet-workshop-airlock before, an idea I am definitely fond of...but an alternate approach is to have a descent stage which includes a ready-built airlock and permanent science/exploration/habitation modules already built in. So you're not expending the descent stage as much as you are using the descent stage for emplacement of base modules. Each new mission adds a new section of the base. 

[tater]

9 hours ago, DDE said:

I think everyone in this thread has forgotten the context of the DSG proposal from a few years back: it was a compromise solution designed to adapt to differing requirements from differing administrations (while not properly committing to either goal).

Never, never, never ever leave politics out of the picture.

While this is completely true, Mars has never been a serious NASA mission for human spaceflight. Not ever. They've yet to fund anything that isn't made of paper on the subject, and they lack the budget to ever do it. International partners are actually interested in the Moon for the simple reason that it's actually possible to do.

1 hour ago, sevenperforce said:

So you're not expending the descent stage as much as you are using the descent stage for emplacement of base modules. Each new mission adds a new section of the base. 

This is possible, but unless the components get attached to each other, it's sort of pointless. Going outside uses expendables every single time, and it's a mess. Ideally a lunar base would have a large airlock, complete with showers in an lesser "airlock" to the hab so that they don't drag dust in (perhaps the airlock between the real airlock and the hab is a shower.

[YNM]

14 hours ago, EchoLima said:

Now somehow it takes three... 

It'll take much more when we build an outpost on the Moon.

[tater]

It takes more launch vehicles since SLS can't do the job itself, and since it's so expensive and complicated to build, it can only fly once a year, so even if they could do it with just 2 launches, that's not a thing, either.

Meanwhile in China:

 

[EchoLima]

20 minutes ago, tater said:

They've yet to fund anything that isn't made of paper on the subject, and they lack the budget to ever do it.

That's because all the funding is going to LOP-G and Orion. It would be far better to just focus on Mars, and develop technologies to get there. A lunar program won't help. 

[tater]

6 minutes ago, EchoLima said:

That's because all the funding is going to LOP-G and Orion. It would be far better to just focus on Mars, and develop technologies to get there. A lunar program won't help. 

Gateway and Orion are sorta pointless, but they don't slow down Mars, NASA was never going to Mars (with humans).

Things NASA doesn't know how to do for Mars (that are critical, and this is not exhaustive at all, just a few bullets):

1. Land large vehicles precisely on Mars ("precisely" means easy walking distance from each other?). Thinking harder here, the vehicles need to also not damage the others upon landing, not trivial on an unprepared surface that will send high velocity ejecta sideways from each landing). They might have to land each in a small crater to shield the neighbors, actually.

2. Have life support that works for years without constant resupply of parts due to break downs.

3. ISRU needs to, you know, actually exist.

4. Have the ability to loft the requisite number of pieces of each Mars transfer vehicle within days of each other. Assume SLS works. the MAV needs a few SLS launches (4 according to NASA I think). The crew vehicle/hab needs 3-4 more. So 8 launches in a couple years, with a vehicle NASA can't possibly fly more that at most twice a year (only with massive budget increases).

Mars is not a thing, and will not ever be a thing unless commercial vehicles obviate SLS entirely.

[StrandedonEarth]

28 minutes ago, tater said:

1. Land large vehicles precisely on Mars ("precisely" means easy walking distance from each other?). Thinking harder here, the vehicles need to also not damage the others upon landing, not trivial on an unprepared surface that will send high velocity ejecta sideways from each landing). They might have to land each in a small crater to shield the neighbors, actually.

Could this be mitigated using a SkyCrane approach, putting the engines farther from the surface? Presumably the farther the engines are from the ground, the smaller/lighter the particles that get kicked up. Still not really ideal.

The only logical approach to basebuilding anywhere, Mun Moon, Mars, or anywhere that isn't a sheet of ice (which would present its own challenges, is that the first lander should be dedicated to building a landing pad. The best way to do that probably depends on the surface composition. Short of mixing up some sort of cement, it might be easiest to melt the surface , which would probably require either nuclear power or some sort of solar focusing arrangement. (lenses or mirrors). Regardless, a berm would need to be built around the LZ, and maybe a higher shield wall to protect  valuable assets. At least if the LZ is on the outskirts, protection is only needed on one side.

Something similar to the OctaGrabber would be useful to remove landed craft from the prepared LZ

Edited February 17, 2019 by StrandedonEarth

[tater]

The ejecta issue is actually critical to the on-topic use of landers at a lunar facility.

Typically I think the idea is to sinter the surface.

 

 

https://sciences.ucf.edu/class/landing-team/the-science-of-plume-effects/

[kerbiloid]

58 minutes ago, tater said:

Things NASA doesn't know how to do for Mars (that are critical, and this is not exhaustive at all, just a few bullets):

1. Land large vehicles precisely on Mars ("precisely" means easy walking distance from each other?). Thinking harder here, the vehicles need to also not damage the others upon landing, not trivial on an unprepared surface that will send high velocity ejecta sideways from each landing). They might have to land each in a small crater to shield the neighbors, actually.

2. Have life support that works for years without constant resupply of parts due to break downs.

3. ISRU needs to, you know, actually exist.

4. Have the ability to loft the requisite number of pieces of each Mars transfer vehicle within days of each other. Assume SLS works. the MAV needs a few SLS launches (4 according to NASA I think). The crew vehicle/hab needs 3-4 more. So 8 launches in a couple years, with a vehicle NASA can't possibly fly more that at most twice a year (only with massive budget increases).

They should just ask Musk. He knows.

P.S.
Why sinter regolith instead of making regolith&plastic bricks for the same purpose.

P.P.S.
...(If they dislike the sand bags.)
Why not make 20 m long plastic sausages, put it around/on top of a module and fill with sand regolith.

P.P.P.S.
... (If they dislike deep and wide trenches to put the modules inside and cover with ground regolith.)

Edited February 17, 2019 by kerbiloid

[tater]

22 minutes ago, kerbiloid said:

Why sinter regolith instead of making regolith&plastic bricks for the same purpose.

Because it’s easy to do in situ for a landing pad that likely needs to be many hundreds of square meters.

Sand bags (the robot rover that smooths the area to be sintered could do this) could be stacked around the landing area as a berm.

[kerbiloid]

7 minutes ago, tater said:

Because it’s easy to do in situ for a landing pad that likely needs to be many hundreds of square meters.

I would be afraid to land a plane on a field of tiles made of sintered regolith with stones and caverns inside.

Upd.
I mean, it's ok to sinter them inside a brick sintering facility from the milled and sorted regolith, stack aside, and then cover the landing place (previously levelled by a dozer).

Edited February 17, 2019 by kerbiloid

[YNM]

1 hour ago, tater said:

Meanwhile in China...

Indeed.

[StrandedonEarth]

2 hours ago, kerbiloid said:

Why sinter regolith instead of making regolith&plastic bricks for the same purpose.

Because plastic would need to be imported. The less that needs to be imported, the better.

1 hour ago, kerbiloid said:

I would be afraid to land a plane on a field of tiles made of sintered regolith with stones and caverns inside.

Except nobody would be landing a plane on the Moon. Presumably the site would be analyzed first to ensure there are no hollow pockets. And really, all the sintering needs to do is ensure there are no pieces light enough to be kicked up by exhaust.

[tater]

Some sintering concepts are presumably sort of 3d printers that collect regolith powder (scoop it up, then sort, then crush everything under a certain scale size). They'd sinter the flat area they scooped from, then go back over it, adding a thin layer of regolith, while sintering that to the previous layer until they get a decent thickness. It likely has to be at least as thick as the concrete that would be required.

[Cunjo Carl]

[-] DecronymAcronyms Explained
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

Fewer Letters	More Letters
ACES	Advanced Cryogenic Evolved Stage
BE-3	Blue Engine-3
CLPS	Commercial Lunar Payload Services
CNSA	China National Space Agency
CSM	Command Service Module (of Apollo)
CPL	Co-manifested Payload (of SLS)
CMP	Configuration Management Plan
DRA	Design Reference Architecture
DSG	Deep Space Gateway
DST	Deep Space Transport
ET	Eastern Time (GMT+4 or GMT+5)
ESA	European Space Agency
EUS	Exploration Upper Stage (of SLS)
hab	Habitat Module
ISS	International Space Station
ISRU	In-situ Resource Utilization
LH2	Liquid Hydrogen
LEO	Low Earth Orbit
LLO	Low Lunar Orbit
LOP-G	Lunar Orbit Platform-Gateway
LOR	Lunar Orbit Rendezvous
LOX	Liquid Oxygen
LZ	Landing Zone
MAV	Mars Ascent Vehicle
MDRA	Mars Design Reference Architecture
MEMS	Micro Electro-Mechanical Systems
MMOD	Micrometeoroids and Orbital Debris
MNA	Mean Anomaly at Epoch (a KSP term)
NASA	(US) National Aeronautics and Space Administration
NRHO	Near Rectilinear Halo Orbit
nav	Navigation
PR	Public Relations
SLS	Space Launch System
Roscosmos	(Russia's Space Agency)
TLI	Trans-Lunar Injection

^{Not actually using Decronym, just figured younger forum goers might want a translation guide for all the TLAs!}

[DDE]

30 minutes ago, Cunjo Carl said:

Not actually using Decronym, just figured younger forum goers might want a translation guide for all the TLAs!

Good bot

[Cunjo Carl]

25 minutes ago, DDE said:

Good bot

Many people are familiar with the Turing test, but the real test of wits for a conscious AI will be to convince people it's still just a bot!

No one here but us chickens...

[sevenperforce]

6 hours ago, tater said:

7 hours ago, sevenperforce said:

I advanced a wet-workshop-airlock before, an idea I am definitely fond of...but an alternate approach is to have a descent stage which includes a ready-built airlock and permanent science/exploration/habitation modules already built in. So you're not expending the descent stage as much as you are using the descent stage for emplacement of base modules. Each new mission adds a new section of the base. 

This is possible, but unless the components get attached to each other, it's sort of pointless. Going outside uses expendables every single time, and it's a mess. Ideally a lunar base would have a large airlock, complete with showers in an lesser "airlock" to the hab so that they don't drag dust in (perhaps the airlock between the real airlock and the hab is a shower.

Well, you don't need that at all if you have a pressurized rover.

The more I think about the idea, the more I like it. Your reusable crew taxi has tanks above, engines on the sides, and a single docking port in the floor. Each mission carries a new surface hab which is left behind at the end of the mission. All hab modules have a docking port in the side for ingress/egress by pressurized rover. Move by rover to any previously-landed module, one of which would be your dedicated airlock.

[tater]

Or add some sort of flexible tube.

[sevenperforce]

13 hours ago, tater said:

Or add some sort of flexible tube.

Possibly, but that does tend to make landing precision a bit hairy unless your flexible tube is really really long (which is its own issue anyway). Unless you have sintered landing pads across the board then you end up with touchdown debris potentially puncturing the tube.

The disadvantage of a rover-based base (LOL) is that you are tied to the rovers to move around, and you are in a bad place if a rover dies, gets stuck, or the like. Can mitigate by having multiple pressurized rovers and by putting suitports in the rover (which you'd probably want anyway) with either a suitport entry or a standard airlock in the hab modules.

NASA could order habitation modules from Bigelow or someone. The nice thing about having a permanent hab serving as the docking port connection to the ascent module is that you can "stretch out" into the hab during the flight to the lunar surface (though of course you'd close the hatch during descent in case you ran into a contingency abort situation). Your ascent capsule can be more of a taxi, which lowers the barrier for access. And there is no particular reason why anyone really needs the docking port on the ceiling; it's just sort of been standard over the years since most vehicles are earth-launched and have a single axial engine underneath.

 

[tater]

Yeah, the idea of a base with multiple habitats (I'm lumping labs, etc as habs, ie: anything people can go inside) ceases to be useful at all if you have to go outside to get to the other buildings, IMHO. At that point, they might as well sortie to different places of interest.

I'd forgotten about relative distance and the risk there.

I suppose alternatively, you land a regolith-moving rover (bulldozer), then land a dedicated airlock hab. Robot berms around the hab, and the next hab lands close (possibly with crew), with the berm protecting it. The berm is cut between the 2, and the flex tube is used to connect them. The distance between the airlock hab and the berm, and between the berm and the new lander would intentionally be just far enough that the robot rover could get between and cut the berm, so this is not an EVA activity. The astronauts then EVA, and connect the 2 habs. They can end their EVA in the airlock, clean up, and use the tube to get back home to their habitat lander. The rover could push some regolith to the side of the tube, and eventually the sintering bot could cover it.

[sevenperforce]

3 minutes ago, tater said:

Yeah, the idea of a base with multiple habitats (I'm lumping labs, etc as habs, ie: anything people can go inside) ceases to be useful at all if you have to go outside to get to the other buildings, IMHO. At that point, they might as well sortie to different places of interest.

If you have a pressurized (shirtsleeve-environment) rover to get from hab to hab, then you can make it work...at least for long enough until you eventually use a crane or whatever to put the habs closer together. 

You'd have dedicated installations...a multipurpose airlock, lab for science, a sleeping area, showers, a hab for food storage and prep, etc.

Each manned landing adds a new component to the base.