Author Topic: Blue Moon Mk1 Single Use Lunar Cargo Lander  (Read 6442 times)

Offline Steve G

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Re: Blue Moon Mk1 Single Use Lunar Cargo Lander
« Reply #20 on: 11/01/2023 11:51 am »
The Mk-2 cargo lander won't be able to carry cargo on top. It will be restricted to where the crew module is located. Way back when, I did a poor rendition of the cargo lander. Here it is again.

I wouldn't be surprised if Blue used a modified component of the Blue Moon architecture for a third stage using the BE-7. Sorry, the first upload attempt for the lander got nuked.
« Last Edit: 11/01/2023 11:54 am by Steve G »

Offline warp99

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Re: Blue Moon Mk1 Single Use Lunar Cargo Lander
« Reply #21 on: 11/04/2023 03:29 am »
Looking at the Mk1 few questions spring to my mind:
- is this self-funded? Are they hoping to get picked up for CLPS or indend to compete for some form of HLS services. I don't remember it being mentioned in the HLS proposal. 
- Is there money/option in Artemis for payload services like this?
- Why design two different vehicles? Can't they make a cargo variant of the Mk2?
- How is the payload going to get unloaded?

I have many of the same questions, plus a few others:

- Are they out of their freakin' minds continuing work on Mark 1?  Why aren't they just doing an HDL version of Mark 2 (Human-Class Delivery Lander, the cargo version of HLS, as specified in the SLD/SLT BAA) and relegating Mark 1 to the dustbin of history?

- Why would Nelson, Melroy, and Free allow themselves to be photographed in front of this thing?

- Is this actually happening, or are they simply using an old Mark 1 mockup to do BE-7 fit checks of some kind?

My Mark 2 (HLS) modeling, using the 16t dry mass stated in the the Blue PR blurbs after source selection, requires 48t of hydrolox to be able to do NRHO-LS(polar)-NRHO, assuming Isp=450s for the BE-7.  This obviously requires refueling in NRHO by the cislunar transport.

But I can get 3t of payload to the lunar surface with no refueling at all if the HDL dry mass is 10t (i.e., the crew module weighs 6t and is removed), and it launches with 40t of prop.  That requires that New Glenn be able to put 53t into LEO, which is more than the magic 45t number.  But the magic 45t number assumes a reusable core.  Doesn't it make a lot more sense just to expend a core for the odd CLPS mission than to engineer two completely different vehicles?

Sometimes I wonder if Jeff actually knows about the sunk-cost fallacy.

I guess the other explanation could be that the NASA PR folks were getting squirrelly about lack of anything that could be shown to the public, and they just wanted the most plausible photo they could get.  I would hope that they had a mockup of Mark 2 available by now, but we are talking about Blue here: step-by-step, with agonizing hesitations between each step.
The key advantages of Mk 1 is that it only requires a single launch of New Glenn to get to the Moon which is a huge advantage compared to Mark 2 which may require up to five launches.  So no refueling requirement, no docking in LEO and NRHO, only one vehicle with a single engine to design, no zero boiloff technology to develop with a 3-4 day mission duration and no worries if landing damages the engine bell. 

So consider it a technology demonstrator in line with SpaceX using Hopper as a technology demonstrator for Starship.  Same engine and guidance system but a much more basic construction and smaller scale.

Offline TheRadicalModerate

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Re: Blue Moon Mk1 Single Use Lunar Cargo Lander
« Reply #22 on: 11/04/2023 04:54 am »
The key advantages of Mk 1 is that it only requires a single launch of New Glenn to get to the Moon which is a huge advantage compared to Mark 2 which may require up to five launches.

That's what I was driving at up above, though:  You should be able to get 3t on a partially fueled Mark 2 pretty close to a lunar landing, with no refueling at all.  It takes about 53t to LEO, which is a bit beyond New Glenn's advertised reusable performance, but it sure seems as if expending a New Glenn would be lot cheaper than managing the engineering for two different landers that have very little to do with one another.

Quote
So consider it a technology demonstrator in line with SpaceX using Hopper as a technology demonstrator for Starship.  Same engine and guidance system but a much more basic construction and smaller scale.

If it weren't Blue, I'd give them the benefit of the doubt for having done the cost/benefit analysis and rationally deciding that maintaining the old platform was worth it.  But they seem to get awfully fond of their ideas early in the cycle, and they just won't let go.

I still think the most likely explanation is that NASA wanted to put Bill in front of something that said "Blue Moon" on the side, and this was the only hunk of finished foam board they had.  That of course would pretty much make the whole press opportunity a lie, but it wouldn't be the first time something like that happened.

I became considerably more jaded when that horrid Christian Davenport animation came out in the WaPo a couple days later.  There were clearly PR flacks in the loop.

Offline warp99

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Re: Blue Moon Mk1 Single Use Lunar Cargo Lander
« Reply #23 on: 11/05/2023 07:47 pm »
The key advantages of Mk 1 is that it only requires a single launch of New Glenn to get to the Moon which is a huge advantage compared to Mark 2 which may require up to five launches.

That's what I was driving at up above, though:  You should be able to get 3t on a partially fueled Mark 2 pretty close to a lunar landing, with no refueling at all.  It takes about 53t to LEO, which is a bit beyond New Glenn's advertised reusable performance, but it sure seems as if expending a New Glenn would be lot cheaper than managing the engineering for two different landers that have very little to do with one another.

Quote
So consider it a technology demonstrator in line with SpaceX using Hopper as a technology demonstrator for Starship.  Same engine and guidance system but a much more basic construction and smaller scale.

If it weren't Blue, I'd give them the benefit of the doubt for having done the cost/benefit analysis and rationally deciding that maintaining the old platform was worth it.  But they seem to get awfully fond of their ideas early in the cycle, and they just won't let go.

I still think the most likely explanation is that NASA wanted to put Bill in front of something that said "Blue Moon" on the side, and this was the only hunk of finished foam board they had.  That of course would pretty much make the whole press opportunity a lie, but it wouldn't be the first time something like that happened.

I became considerably more jaded when that horrid Christian Davenport animation came out in the WaPo a couple days later.  There were clearly PR flacks in the loop.

There is a considerable assumption in this modified Mark 2 scenario which is that you can replace a crew cabin massing 6 tonnes with nothing.  I am not sure that the crew cabin is that high a percentage of the 16 tonnes of dry mass but even if it is a cargo lander needs a load platform, fold out ramps or davits and enough structure to support the landing legs on the sides and the engines on the bottom. 

Note that the (toroidal?) LOX tank is used as the main structural member but that still needs to be tied to the crew cabin replacement structure to take the thrust of the engines and more importantly the considerable load of fully fuelled propellant tanks during launch.
« Last Edit: 11/05/2023 07:49 pm by warp99 »

Offline TheRadicalModerate

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Re: Blue Moon Mk1 Single Use Lunar Cargo Lander
« Reply #24 on: 11/05/2023 09:05 pm »
There is a considerable assumption in this modified Mark 2 scenario which is that you can replace a crew cabin massing 6 tonnes with nothing.  I am not sure that the crew cabin is that high a percentage of the 16 tonnes of dry mass but even if it is a cargo lander needs a load platform, fold out ramps or davits and enough structure to support the landing legs on the sides and the engines on the bottom. 

Note that the (toroidal?) LOX tank is used as the main structural member but that still needs to be tied to the crew cabin replacement structure to take the thrust of the engines and more importantly the considerable load of fully fuelled propellant tanks during launch.

I assume that Blue bid the human-class delivery lander (HDL) option, so there's some kind of cargo delivery configuration.  However, I admit that the 6t for the crew module is a sheer wild-ass guess.  Seems about right for a crew of 4, though.

I'm pretty sure that the LOX tank isn't toroidal, but rather just an ellipsoidally capped cylinder with zero-height cylinder walls.

I'm >95% confident that the HDL version will have a variant of the "nothing" that you were objecting to.  The real limitation with the HDL isn't the empty space; it's the restrictions that the finite empty space puts on the payloads.  They have to be low enough profile that they fit in the gap, and there absolutely has to be some set of trusses that transmit thrust, so the payload can only be so wide to fit through the gaps. 

Another SWAG:  That the landing leg receptacles are part of the load transmission system, i.e., there will be four trusses, spaced 90 apart.  If they get really clever, the trusses may swing out when the legs deploy, providing more deployment space between them.

PS:  You're right that some amount of dry mass is required for deployment, but Blue may be counting that as "payload".  That's what usually happens with launchers, isn't it?
« Last Edit: 11/05/2023 09:07 pm by TheRadicalModerate »

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