Blue Moon Lunar Lander

[Steve G]

If you look at the hi-resolution pictures of the EVA training, in the top photo, you can see through the hatch and see a circular tubular structure in the middle. Also, on the bottom of the simulator, there is a half-moon cut out in the half-moon simulator that might represent the conduit corridor for the fuel. How that affects livingspace, is TBA.

[TheRadicalModerate]

If you look at the hi-resolution pictures of the EVA training, in the top photo, you can see through the hatch and see a circular tubular structure in the middle. Also, on the bottom of the simulator, there is a half-moon cut out in the half-moon simulator that might represent the conduit corridor for the fuel. How that affects livingspace, is TBA.

That shot in the video from the top of the mock-up, with the dummy, which is presumably about 5' 10" long, lets us estimate how wide that pathway is around the central cylindrical thingy.  Figure the dummy is sticking about 2.5' through the hatch, and there's about 2' between it and the thingy, and we're looking at about 1.4m  If the vehicle is 6.2m wide (the width of the static envelope for the NG fairing), that would make the thingy 3.4m wide, which is clearly wrong.

Seems like whatever that thing is, it's not a central conduit corridor, or at least it's not a coaxial corridor.  Seems like an off-axis half-moon shape is indeed correct, but why would you put prop lines off-axis but still on the inside of the vehicle?

Seems weird to have something like that restricting access to the hatch.  No clue what it is.

[JCRM]

Seems like whatever that thing is, it's not a central conduit corridor, or at least it's not a coaxial corridor. 

It seems a strange place to put it, but if they did run the propellant through the middle, I'd imagine they'd arrange a lot of the other "internals" in there too. cryogenic system  (fuel cells?) water storage, suit stowage, other lockers.

[catdlr]

Seems like whatever that thing is, it's not a central conduit corridor, or at least it's not a coaxial corridor. 

It seems a strange place to put it, but if they did run the propellant through the middle, I'd imagine they'd arrange a lot of the other "internals" in there too. cryogenic system  (fuel cells?) water storage, suit stowage, other lockers.

Similar to the New Shepard capsule, the substantial spherical object situated within the New Shepard crew cabin contains the retro rockets and their supporting apparatus. In the context of the BMLL, this will be represented by a cylindrical structure extending from the floor to the ceiling, which will accommodate the propulsion system (rocket). It may produce considerable noise.  Consider it a crew cabin ring surrounding the rocket cabin, ie, a donut.

[meekGee]

Seems like whatever that thing is, it's not a central conduit corridor, or at least it's not a coaxial corridor. 

It seems a strange place to put it, but if they did run the propellant through the middle, I'd imagine they'd arrange a lot of the other "internals" in there too. cryogenic system  (fuel cells?) water storage, suit stowage, other lockers.

If you're making a dog yard, it's best to put a big obstacle in the middle so they can go running around it, it makes the yard seem larger to the occupants.

Just saying.

[Nonexistence]

In light of recent attempts to land on the moon with tallish landers has this image produced any second thoughts or mitigation solutions to the high center of mass and narrow footprint? Or does Blue have it solved?
Or have the failed landings been mostly guidance control errors?

[sstli2]

In light of recent attempts to land on the moon with tallish landers has this image produced any second thoughts or mitigation solutions to the center of mass and narrow footprint? Or does Blue have it solved?
Or have the failed landings been mostly guidance control errors?

We know the issue is not center-of-mass because despite all the ruckus about the IM lander, it has all of its propellant and heavy components like engines on the bottom. It doesn't actually have a high center-of-mass.

Further, if there was some inherent problem with tall landers, Starship would be screwed. It's way more dimensionally skewed than Blue Moon is.

Intuitive Machines assessment of root cause for both IM-1 and IM-2 was issues with their lidars. I see not reason to believe this. If your sensors aren't working, and you don't have adequate redundancy, you're destined for failure, barring some contraption like Mars Pathfinder.

Alas it seems the Internet will continue to lose their minds over tall lunar landers.

[Nonexistence]

Lol not losing my mind yet

The image unfortunately raised the idea for me again.

The horse is dead I suppose.

[JCRM]

Seems like whatever that thing is, it's not a central conduit corridor, or at least it's not a coaxial corridor. 

It seems a strange place to put it, but if they did run the propellant through the middle, I'd imagine they'd arrange a lot of the other "internals" in there too. cryogenic system  (fuel cells?) water storage, suit stowage, other lockers.

If you're making a dog yard, it's best to put a big obstacle in the middle so they can go running around it, it makes the yard seem larger to the occupants.

Just saying.

more to the point, if you need to let one go, you can walk around to the other side, and deny all knowledge.

[meekGee]

Seems like whatever that thing is, it's not a central conduit corridor, or at least it's not a coaxial corridor. 

It seems a strange place to put it, but if they did run the propellant through the middle, I'd imagine they'd arrange a lot of the other "internals" in there too. cryogenic system  (fuel cells?) water storage, suit stowage, other lockers.

If you're making a dog yard, it's best to put a big obstacle in the middle so they can go running around it, it makes the yard seem larger to the occupants.

Just saying.

more to the point, if you need to let one go, you can walk around to the other side, and deny all knowledge.

Actually a bit of visual privacy is not that bad an idea. There's definitely up sides to this.

I can formalize my theory by saying that the apparent size of an enclosure corresponds to the shortest path from side to side.  So from a human factor perspective, a central obstacle increases the apparent size of the habitat.

[sdsds]

Actually a bit of visual privacy is not that bad an idea. [...] from a human factor perspective, a central obstacle increases the apparent size of the habitat.

This. The abort motor in the middle of the New Glenn capsule, even though it doesn't extend all the way to the ceiling as this Blue Moon downcomer would do, nonetheless provides each customer with a slightly more personal ride experience. This even works to some extent with the wheel on the Disney Teacups ride: it's okay that strange humans are sitting way over there on the other side of the wheel. <End Murderbot mode>

[Probably Fine]

Actually a bit of visual privacy is not that bad an idea. [...] from a human factor perspective, a central obstacle increases the apparent size of the habitat.

This. The abort motor in the middle of the New Glenn capsule, even though it doesn't extend all the way to the ceiling as this Blue Moon downcomer would do, nonetheless provides each customer with a slightly more personal ride experience. This even works to some extent with the wheel on the Disney Teacups ride: it's okay that strange humans are sitting way over there on the other side of the wheel. <End Murderbot mode>

I propose we call it the Hibachi Effect

[sstli2]

Actually a bit of visual privacy is not that bad an idea. [...] from a human factor perspective, a central obstacle increases the apparent size of the habitat.

This. The abort motor in the middle of the New Glenn capsule, even though it doesn't extend all the way to the ceiling as this Blue Moon downcomer would do, nonetheless provides each customer with a slightly more personal ride experience. This even works to some extent with the wheel on the Disney Teacups ride: it's okay that strange humans are sitting way over there on the other side of the wheel. <End Murderbot mode>

Regardless, the crew module will be an unprecedented 7m in diameter, and cylindrical and not conical, so even with space occupied for fuel lines I don't think habitable space will be a problem. It will dwarf Shuttle, Dragon, Starliner, and Orion (and of course, Starship will dwarf it).

[TheRadicalModerate]

Regardless, the crew module will be an unprecedented 7m in diameter, and cylindrical and not conical, so even with space occupied for fuel lines I don't think habitable space will be a problem. It will dwarf Shuttle, Dragon, Starliner, and Orion (and of course, Starship will dwarf it).

6.3m.  See diagram from the old New Glenn payload user guide.

Why would you put LH2 and LOX downcomers through a place that's supposed to be warm?  It makes the warm place colder, and the prop warmer.¹

It's probably a console or a bulkhead, not a downcomer.  However, I still don't understand why you wouldn't provide a straight shot into the crew cabin for the hatch.

Note that the hatch and the docking port are not the same thing.  I suppose it's possible that they prioritized straightforward access through the docking tunnel over access to the hatch.  After all, they'll have to load consumables and pressurized payloads through the docking tunnel.

___________
¹One could argue that it might be useful to cool the crew module during lunar daylight.  But we already know they're adopting a zero-boiloff architecture for their propellants, which means that they're just converting a fairly simple air cooling problem in the range of 20-30ºC into a cryocooling problem in the range of 20-90K.

Also, who wants to deal with the fights about who gets the bed next to the liquid hydrogen?

[sdsds]

Why would you put LH2 and LOX downcomers through a place that's supposed to be warm?  It makes the warm place colder, and the prop warmer.

If in fact this is the design it seems likely to include vacuum jacketing and thermally reflective coatings.

I still don't understand why you wouldn't provide a straight shot into the crew cabin for the hatch.

Even 6m diameter is huge. Take out a meter for the central column and the circular corridor is still 2.5m wide so ingress/egress through the side hatch looks like it would have comfy margins even for suited astronauts.

I don't understand how the crew would get past the propellant tanks if they entered through a docking port on top though. Does that diagram show both the hatch and the port on the crew cylinder? Orion would dock sideways?

[Nonexistence]

Are the tanks donut shaped up top to facilitate a tunnel to the docking port?

[Steve G]

The docking hatch is on the side of the crew cabin and not the top. You can see it on the renderings on the left side.

[sstli2]

6.3m.  See diagram from the old New Glenn payload user guide.

Why would you put LH2 and LOX downcomers through a place that's supposed to be warm?  It makes the warm place colder, and the prop warmer.¹

Do we know that it will even be launched with a fairing? And given the interior diameter will be less than 7m regardless, this seems like a pointless nitpick.

Also, why would there be any meaningful quantity of propellant in these lines when the engines are not firing? The BE-7s will only be fired for actual maneuvers, which is a tiny fraction of the actual trip, and not at all on the surface. Perhaps they could purge the lines upon engine shutdown. At other times, they do need to maintain attitude with thrusters, but that I assume will not be using cryogenics at all.

Finally, the MK II lander is pre-CDR. There are likely already numerous design changes from the initial drawing and your guess is as good as mine as to what it will actually look like. I'm going to bet you see a material evolution of the design, just like Starship HLS went from having solar panels on the body to extended ones (and likewise remains pre-CDR).

[sdsds]

Of course the attached diagram is entirely conceptual. Still it looks spacious for a crew of four. Plus the central column has the advantage that a wall is always close-by. My understanding is that astronauts in zero-g want this.

[clongton]

If I were on the design team, which I am not, I would recommend placing the engines above the crew cabin, below the tanks, canted outward to keep the exhaust plume away from the airframe. This also has the advantage of not blasting the landing spot beneath the lander. This leaves the crew cabin a nice clean design with easy access to the surface. It also allows for a cargo version that can lower the entire bottom (the floor) to the lunar surface for removal of the cargo. The only reason to put the engines on the bottom is tradition. There is absolutely no technical reason to continue doing that. It works fine for launch vehicles, but for landers on the moon, there is no reason not to have the cabin/cargo hold on the bottom instead.