Author Topic: NASA HLS (Human Landing System) Lunar Landers  (Read 757277 times)

Offline Exastro

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2500 on: 08/13/2021 12:07 am »
Perhaps strangely, a normal Starship could do the LEO->Lunar Surface->LEO trip with plenty of payload, because it has the advantage of using aerobraking on the return leg.  I suspect the reason that's not being done is that NASA isn't comfortable with a manned Starship EDL.  Of course they must have considered putting the crew in a capsule just ahead of reentry, but appear to have rejected that for some reason.

What assumptions are you using?  How big a crew module?  I can't get LEO-LS-LEOAero to work with 1200t of prop, 120t dry, and (my assumption) a 20t crew module.  I can get a 95t dry + 20t crew + 1400t prop LSS to make it back, but of course it can't aerobrake--at least not in one pass.

I screwed up and forgot to include the 1.87 km/sec needed to get from the Lunar surface to LLO.  Apologies for that!

I assumed a mVeh = 130*tonne Starship, total dV = (5.93+1.87+1 = 8.8) km/sec after fixing the above error, exhaust velocity vEx = 375*sec*gee = 3.679 km/sec (Rvac only burn), starting propellant mass in LEO mProp = 1200*tonne, and computed the resulting payload, including the crew cabin and propellant residuals, using:

mPay = (mVeh*exp(dV/vEx)-mVeh-mProp)/(1-exp(dV/vEx))

This gives mPay = -9*tonne, unfortunately, which means my post was qualitatively wrong.

If I change the assumed mVeh to (95+20)*tonne and the assumed mProp to 1400*tonne I get 25.9*tonne (including propellant residuals) back through TEI.  But of course, as you point out, you don't want to do that in a Starship without a heat shield unless you're willing to expend it and it's packing an Orion (which might actually work if it can do EDL without the ESM, hmm...)

OTOH the standard Starship makes a dandy shuttle between LEO and LLO.  I'm finding a round-trip payload of 278*tonne, which seems to make it capable of carrying a 30*tonne (dry) single-stage lander and its propellant for one sortie with plenty of reserve capacity.


(Edit: formatting and a typo)
« Last Edit: 08/13/2021 12:14 am by Exastro »

Offline TrueBlueWitt

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2501 on: 08/13/2021 01:12 am »
Perhaps strangely, a normal Starship could do the LEO->Lunar Surface->LEO trip with plenty of payload, because it has the advantage of using aerobraking on the return leg.  I suspect the reason that's not being done is that NASA isn't comfortable with a manned Starship EDL.  Of course they must have considered putting the crew in a capsule just ahead of reentry, but appear to have rejected that for some reason.

What assumptions are you using?  How big a crew module?  I can't get LEO-LS-LEOAero to work with 1200t of prop, 120t dry, and (my assumption) a 20t crew module.  I can get a 95t dry + 20t crew + 1400t prop LSS to make it back, but of course it can't aerobrake--at least not in one pass.

I screwed up and forgot to include the 1.87 km/sec needed to get from the Lunar surface to LLO.  Apologies for that!

I assumed a mVeh = 130*tonne Starship, total dV = (5.93+1.87+1 = 8.8) km/sec after fixing the above error, exhaust velocity vEx = 375*sec*gee = 3.679 km/sec (Rvac only burn), starting propellant mass in LEO mProp = 1200*tonne, and computed the resulting payload, including the crew cabin and propellant residuals, using:

mPay = (mVeh*exp(dV/vEx)-mVeh-mProp)/(1-exp(dV/vEx))

This gives mPay = -9*tonne, unfortunately, which means my post was qualitatively wrong.

If I change the assumed mVeh to (95+20)*tonne and the assumed mProp to 1400*tonne I get 25.9*tonne (including propellant residuals) back through TEI.  But of course, as you point out, you don't want to do that in a Starship without a heat shield unless you're willing to expend it and it's packing an Orion (which might actually work if it can do EDL without the ESM, hmm...)

OTOH the standard Starship makes a dandy shuttle between LEO and LLO.  I'm finding a round-trip payload of 278*tonne, which seems to make it capable of carrying a 30*tonne (dry) single-stage lander and its propellant for one sortie with plenty of reserve capacity.


(Edit: formatting and a typo)

Even without Tiles, Lunar Starship can still do significant areobraking.
It just can't do it all in one pass, it would have to skip a few times. Correct?
« Last Edit: 08/13/2021 01:13 am by TrueBlueWitt »

Offline Exastro

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2502 on: 08/13/2021 03:20 am »
Perhaps strangely, a normal Starship could do the LEO->Lunar Surface->LEO trip with plenty of payload, because it has the advantage of using aerobraking on the return leg.  I suspect the reason that's not being done is that NASA isn't comfortable with a manned Starship EDL.  Of course they must have considered putting the crew in a capsule just ahead of reentry, but appear to have rejected that for some reason.

What assumptions are you using?  How big a crew module?  I can't get LEO-LS-LEOAero to work with 1200t of prop, 120t dry, and (my assumption) a 20t crew module.  I can get a 95t dry + 20t crew + 1400t prop LSS to make it back, but of course it can't aerobrake--at least not in one pass.

If I change the assumed mVeh to (95+20)*tonne and the assumed mProp to 1400*tonne I get 25.9*tonne (including propellant residuals) back through TEI.  But of course, as you point out, you don't want to do that in a Starship without a heat shield unless you're willing to expend it and it's packing an Orion (which might actually work if it can do EDL without the ESM, hmm...)


Even without Tiles, Lunar Starship can still do significant areobraking.
It just can't do it all in one pass, it would have to skip a few times. Correct?


I don't have a good answer to that rather interesting question, so here's a bad one:

For an unshielded ship the rate at which you can aerobrake is set by the maximum thermal flux info the skin, which is a function of the ship's speed through the air and the density of the air it's passing through.  (I think it goes like the cube of the speed times the density, but take that with a grain of salt).  Without enough propellant to brake you can't do much about the speed, which is going to be very roughly 10 km/sec (IIRC), but if you maneuver early you can still control how deeply you enter the atmosphere and hence the max air density you face. 

The hard part of this is figuring out how much thermal flux the ship can take.  The limiting factor is the softening of the metal skin, which depends on its temperature, which in turn is mostly set by the balance between (friction heat + radiation from the shock) vs radiation by the skin itself.  Since the skin radiation goes like the fourth power of the ship's surface temperature, even a modest loss in the skin's ability to handle high temperatures does a lot to reduce the effectiveness of the aerobraking it can survive. 

Based on that, I think the unshielded ship will have to do a whole bunch of passes through the upper atmosphere before it can get to something like LEO.  And I think most of those passes are going to reach apogees above or inside the inner Van Allen belt, which is a really nasty place to spend time if you're not carrying a massive radiation shield, which if you could you'd probably be better off bringing the heat shield instead.

So I think this kind of aerobraking might possibly be practical for bringing an unmanned ship home, but not a manned ship.  You could consider having the crew bail out in an Orion for a direct EDL while the ship spends weeks(?) working its way home to LEO, but again, if you have the mass performance for that it's probably better to use it to put a heat shield on the ship.

« Last Edit: 08/13/2021 03:21 am by Exastro »

Online TheRadicalModerate

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2503 on: 08/13/2021 04:39 am »
Even without Tiles, Lunar Starship can still do significant areobraking.
It just can't do it all in one pass, it would have to skip a few times. Correct?

Multi-pass aerobraking with a crew is a terrible idea.  You get two full Van Allen Belt transits per pass.  But if you had a direct reentry vehicle (a D2, for example), you could send the crew home straight to EDL but then brake the LSS over a period of a couple of months.

If you're interested, there was a thread about how to do this here.  Opinions ranged from this being pretty easy to it being impossible.

Online MaxTeranous

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2504 on: 08/13/2021 07:42 am »
That isn’t an issue for Artemis 3 ofc, as the crew will be coming back on Orion. But I can certainly see SpaceX trying it anyway post transfer, as at that point the LSS primary mission is over. Using the asset to gather data and maybe get it back into LEO is very SpaceX, the equivalent of the test booster landings in the early days of reusability.

Offline TorenAltair

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2505 on: 08/13/2021 09:29 am »
Did we have this post-GAO-decision „info“graphic already?

https://www.blueorigin.com/assets/lunar-starship-complexity-infographic.jpg

Offline joek

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2506 on: 08/13/2021 09:40 am »
Did we have this post-GAO-decision „info“graphic already?
Yes.
edit: Doh, yeah, looks like this is new.
« Last Edit: 08/13/2021 09:55 am by joek »

Offline ugordan

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2507 on: 08/13/2021 09:44 am »
Did we have this post-GAO-decision „info“graphic already?

https://www.blueorigin.com/assets/lunar-starship-complexity-infographic.jpg

This is a new one to me.

Offline TorenAltair

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2508 on: 08/13/2021 09:47 am »
Did we have this post-GAO-decision „info“graphic already?
Yes.
It is a different image as in your link or I am dumb and blind. This one is referencing the GAO decision.
« Last Edit: 08/13/2021 09:47 am by TorenAltair »

Offline joek

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2509 on: 08/13/2021 10:03 am »
Sorry, yup, that's new; edited previous comment.
Document properties for this one shows it was created 12-Aug.

If you scroll down to the end of the page https://www.blueorigin.com/blue-moon/national-team
looks like they have consolidated pro-National anti-whoever collateral.
EXPERT: SECOND LANDER LEGAL THROUGH APPENDIX H
WHY APPENDIX N/LETS WON'T WORK
NASA'S DECISION WRONG FOR USA SPACE LEADERSHIP
SECOND LUNAR LANDER IS REQUIRED
« Last Edit: 08/13/2021 10:12 am by joek »

Online meekGee

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2510 on: 08/13/2021 09:44 pm »
I think this encapsulates Blue’s current position:

https://twitter.com/sciguyspace/status/1425623692323835905

Quote
Take our deal or we sue. That’s the offer on the table now from Blue Origin? Remarkable.

You don’t talk about leaving open the possibility of further legal action unless you at least want the other party (NASA) to think that you’re prepared to take such action, if you don’t reach agreement first.

Edit to add:

As pointed out in tweet below, a few years ago Jeff Bezos gave a pretty accurate comparison of 60s Apollo program speed vs today

https://twitter.com/delta_v/status/1425835300484358153

Quote
This will never not be funny.
It just occurred to me, with all the BS that's flying around, Bezos has an implicit threat available to him - he can pack up his toy and go home, leaving ULA with no future rocket, and the USG at an awkward position.

So the USG basically has to call his bluff, relying on the fact that such a move will probably also irreversibility damage BO..
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Offline tssp_art

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2511 on: 08/13/2021 11:13 pm »
Does anyone know if the Blue Origin and Dynetics base contracts were extended? Not the proposals, but the base contracts for HLS. They were both due to expire on 9-August and Blue was pleading for a no cost extension to keep open the possibility of an award under that contract.

Online niwax

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2512 on: 08/14/2021 12:01 am »
I think this encapsulates Blue’s current position:

https://twitter.com/sciguyspace/status/1425623692323835905

Quote
Take our deal or we sue. That’s the offer on the table now from Blue Origin? Remarkable.

You don’t talk about leaving open the possibility of further legal action unless you at least want the other party (NASA) to think that you’re prepared to take such action, if you don’t reach agreement first.

Edit to add:

As pointed out in tweet below, a few years ago Jeff Bezos gave a pretty accurate comparison of 60s Apollo program speed vs today

https://twitter.com/delta_v/status/1425835300484358153

Quote
This will never not be funny.
It just occurred to me, with all the BS that's flying around, Bezos has an implicit threat available to him - he can pack up his toy and go home, leaving ULA with no future rocket, and the USG at an awkward position.

So the USG basically has to call his bluff, relying on the fact that such a move will probably also irreversibility damage BO..

Not only would this mean significant contract cancellation payments, no one working at BO would ever get near a public contract again. Oh, and handing all national security launches over the next decade to SpaceX.
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Online meekGee

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2513 on: 08/14/2021 12:03 am »
It just occurred to me, with all the BS that's flying around, Bezos has an implicit threat available to him - he can pack up his toy and go home, leaving ULA with no future rocket, and the USG at an awkward position.

So the USG basically has to call his bluff, relying on the fact that such a move will probably also irreversibility damage BO..

Not only would this mean significant contract cancellation payments, no one working at BO would ever get near a public contract again. Oh, and handing all national security launches over the next decade to SpaceX.
Yup agreed.  That's why take toy and go home.  Still a valid threat though.  He can have other hobbies, he doesn't HAVE to play space engineer.

How credible is such a threat?  Depends how dejected he appears to be...
« Last Edit: 08/15/2021 02:09 am by meekGee »
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Offline Kiwi53

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2515 on: 08/14/2021 01:21 am »
Yup agreed.  That's why take toy and go home.  Still a valid threat though.  He can have other hobbies, he doesn't HAVE to play space engineer.

How credible is such a threat?  Depends how dejected he appears to be...
That almost seems like a decision that would burn bridges for his whole empire. If I'm the military (or any other department), do I want to trust my cloud infrastructure to the guy who just threw a tantrum and screwed up a bunch of my national security launches?

Maybe there's nothing they could do in the bid process (at least not openly) for JEDI 2.0 or whatever, especially as Amazon is totally, 100% not affiliated with BO (why would you even think that?), but I can't imagine it would get Amazon brownie points.

Personally, I find BO's argument to be backwards. I want NASA to be pushing the boundaries and striving for something game-changing, even if the risk is greater (not that it necessarily is in this case). I don't want them spending billions of dollars on a slightly better version of Apollo that reuses a bunch of parts we have lying around, especially if pushing the boundaries is eminently achievable.

I want this to be the next Apollo in vision, not just a copy of Apollo's capability!

Offline yg1968

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2516 on: 08/14/2021 05:19 am »
Does anyone know if the Blue Origin and Dynetics base contracts were extended? Not the proposals, but the base contracts for HLS. They were both due to expire on 9-August and Blue was pleading for a no cost extension to keep open the possibility of an award under that contract.

As mentioned elsewhere, Blue's contract for the base period now ends on August 23rd. Dynetics has completed their base period contract (it ended on August 9th).

SpaceX's contract is slighter higher than before at $3B ($3,031,455,921.24 to be more precise). The current end date of SpaceX's contract is Feb 28th 2025. SpaceX received $300M on July 30th (on the day that the protests were denied). See the links below.

Over on reddit user spacerfirstclass dug up total contract value numbers for HLS: https://www.reddit.com/r/spacex/comments/hkju5i/total_contract_values_for_nasa_human_landing/

The whole post is worth reading but it comes down to this:
SpaceX award 80MSFC20C0034: Total Contract Value $2.252B
Dynetics award 80MSFC20C0035: Total Contract Value $5.273B
Blue Origin award 80MSFC20C0020: Total Contract Value: $10.182B

The links are the following ones:

SpaceX:
https://www.usaspending.gov/award/CONT_AWD_80MSFC20C0034_8000_-NONE-_-NONE-
Dynetics:
https://www.usaspending.gov/award/CONT_AWD_80MSFC20C0035_8000_-NONE-_-NONE-
Blue:
https://www.usaspending.gov/award/CONT_AWD_80MSFC20C0020_8000_-NONE-_-NONE-
« Last Edit: 08/14/2021 05:43 am by yg1968 »

Offline pochimax

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2517 on: 08/14/2021 10:01 am »
There is no need for an "authorization to proceed", like in the Dragon XL contract? (than hasn' t happened yet in that case AFAIK)

Offline VaBlue

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2518 on: 08/14/2021 11:06 am »
There is no need for an "authorization to proceed", like in the Dragon XL contract? (than hasn' t happened yet in that case AFAIK)

There is always an ATP, there has to be.  Although, once the contracts are signed, the ATP is little more than a milestone date on which the schedule starts.  There's usually a kick-off meeting, where the contractors and gov't both outline there readiness to start (ie: showing that personnel, processes, facilities, etc are in place and ready to go), and its usually packaged with the ATP milestone on the program schedule.  But it's mostly a schedule formality once the contract is signed by all the various lawyers and fiducial authorities on both sides.

Offline joek

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #2519 on: 08/14/2021 11:46 am »
There is no need for an "authorization to proceed", like in the Dragon XL contract? (than hasn' t happened yet in that case AFAIK)
There is always an ATP, there has to be.  Although, once the contracts are signed, the ATP is little more than a milestone date on which the schedule starts.  There's usually a kick-off meeting, where the contractors and gov't both outline there readiness to start (ie: showing that personnel, processes, facilities, etc are in place and ready to go), and its usually packaged with the ATP milestone on the program schedule.  But it's mostly a schedule formality once the contract is signed by all the various lawyers and fiducial authorities on both sides.

Yes, as noted in the BAA; e.g., "Proposed long lead purchases are only allowed beginning one month after ATP. Each long lead item shall be proposed as a separate sub-CLIN". (IIRC there is a more detailed list of post-ATP gates but can't find it.)

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