totm dec 2023 Artemis Discussion Thread

[jinnantonix]

On 5/1/2020 at 12:15 PM, tater said:

Yeah, they said launch vehicle agnostic. They could potentially send 1 drop tank with a SpaceX cargo delivery (already a thing) as DragonXL unpressurized cargo, perhaps? Send another with some other LV, and the lander with Vulcan?

I personally like the look of the Dynetics option, mainly because it is LV agnostic.  The BO and SpaceX options will be designed and costed to use their own launch systems, and that is not ideal for enhanced commercial competition.  So I am putting my money on Dynetics to be the 2024 lander.

Also obviously Dynetics will not use EUS as shown in the video, I reckon that was just sucking up to NASA  with a sly "SLS is awesome" shoe-horned into their submission.  Savvy sales.  And also does not give away the commercial carrier that will be commissioned to do the TLI injection.

With regard to the Blue Origin lander, I need to think about how Northrup Grumman would build the transit stage, likely it will be low mass, low thrust, hypergolic fueled, probably multiple BT-4 thrusters as used on the Cygnus SM.  This will get the craft from TLI to NRHO at least, and likely also in progressive circularising to LLO.   Interesting to see that the design includes laterally ejected drop tanks in the descent phase - I like the idea, it is very efficient.  Also expect that the ascent phase engines are ejected prior to LLO, and the lander can proceeds to NRHO on hypergolic thrusters.

Edited May 5, 2020 by jinnantonix

[tater]

5 minutes ago, jinnantonix said:

Also obviously Dynetics will not use EUS as shown in the video, I reckon that was just sucking up to NASA  with a sly "SLS is awesome" shoe-horned into their submission.  Savvy sales.  And also does not give away the commercial carrier that will be commissioned to do the TLI injection.

https://www.dynetics.com/newsroom/news/2020/dynetics-to-develop-nasas-artemis-human-lunar-landing-system

Their website says:

Quote

The Dynetics HLS can be fully integrated and launched on the Space Launch System (SLS) Block 1B vehicle. For commercial launches, it can be flown aboard United Launch Alliance's Vulcan Centaur rocket.

Even though the NASA site says LV agnostic.

[jinnantonix]

21 minutes ago, tater said:

https://www.dynetics.com/newsroom/news/2020/dynetics-to-develop-nasas-artemis-human-lunar-landing-system

Their website says:

Even though the NASA site says LV agnostic.

As mentioned previously, the reference to SLS as a potential  LV is likely just salesmanship.  Vulcan will be cheaper, much cheaper.

[ndiver]

A small test done to compare the size of the landers (according to the size of the astronauts, LEM included for comparison):

[Exoscientist]

15 hours ago, tater said:

The Dynetics lander vid shows it attached to EUS. This implies it is north of 40 tons.

I like the lander, but unless they can send it in pieces, it's dead to me, lol. Any profile that requires 2 SLS launches is idiotic.

 

 

 An EUS can also mean a smaller lander that you want to send to the Moon with a single launch of the SLS.

 The Boeing EUS is unaffordable. But there will be several cryogenic upper stages that will be available as early as 2021 that could be used for a much cheaper EUS:

  Bob Clark

Edited May 1, 2020 by Exoscientist

[tater]

9 minutes ago, Exoscientist said:

 The Boeing EUS is unaffordable. But there will be several cryogenic upper stages that will be available as early as 2021 that could be used for much cheaper EUS:

Yeah, that would be ideal, but I don't see it happening. Heck, a Centaur upper stage would be the gold standard (or ACES).

[Exoscientist]

7 minutes ago, tater said:

Yeah, that would be ideal, but I don't see it happening. Heck, a Centaur upper stage would be the gold standard (or ACES).

 

 We can always be optimistic. There is no law that Boeing has to build the EUS, especially since it already has the contract for the SLS core stage.

 Perhaps we can start a letter writing campaign to Bridenstine to open up a competition for the EUS, like they did for the lander, with preference for the cryogenic upper stages already being planned.

 

  Bob Clark

Edited May 1, 2020 by Exoscientist

[ndiver]

I just realized that the solar panel of the Lunar Starship are on the top around the nose (the large dark navy blue zone).

[tater]

Just now, ndiver said:

I just realized that the solar panel of the Lunar Starship are on the top around the nose (the large dark navy blue zone).

Yeah, I might have said it in another thread, but this is ideal for a polar landing site on a crater rim with a grazing sun angle (being up high).

[ndiver]

7 minutes ago, tater said:

Yeah, I might have said it in another thread, but this is ideal for a polar landing site on a crater rim with a grazing sun angle (being up high).

Not really, the more efficient for polar landing site is the solution of Dynetics with vertical solar panels.
The problem of the Starship solar panels in polar landing is that 50% of them are in the shadow and they cannot be orientated to maximize the energy flow they receive. But that's probably compensated by advantages as strength and massive surface.

Edited May 1, 2020 by ndiver

[tater]

22 minutes ago, ndiver said:

Not really, the more efficient for polar landing site is the solution of Dynetics with vertical solar panels.
The problem of the Starship solar panels in polar landing is that 50% of them are in the shadow and they cannot be orientated to maximize the energy flow they receive. But that's probably compensated by advantages as strength and massive surface.

Yeah, but the area is still huge, and there is nothing to deploy, so no failure modes. Like everything else, a trade off.

[RCgothic]

Also starship can spare the mass budget for a slightly inefficient and therefore oversize solar array.

Edited May 1, 2020 by RCgothic

[EchoLima]

My guess is NASA goes with Dynetics, at least for the early non-sustainable landings. 

Blue Origin's lander is overly complex, and who knows when a flight ready Starship will be available. The more hardware available by the time the administration changes, the less likely it will be for Artemis to be cancelled, so I think Dynetics is the best option - their lander is the smallest and presumably simplest to build.

[Nightside]

56 minutes ago, EchoLima said:

My guess is NASA goes with Dynetics, at least for the early non-sustainable landings. 

Blue Origin's lander is overly complex, and who knows when a flight ready Starship will be available. The more hardware available by the time the administration changes, the less likely it will be for Artemis to be cancelled, so I think Dynetics is the best option - their lander is the smallest and presumably simplest to build.

As long as it can launch on an existing rocket, like Delta IV Heavy, or Atlas its a safe bet. They are partnered with ULA, so it seems likely. Hopefully their Vulcan will be live-long-and-prospering by then, but better not to count on it.

[tater]

1 hour ago, EchoLima said:

My guess is NASA goes with Dynetics, at least for the early non-sustainable landings. 

Blue Origin's lander is overly complex, and who knows when a flight ready Starship will be available. The more hardware available by the time the administration changes, the less likely it will be for Artemis to be cancelled, so I think Dynetics is the best option - their lander is the smallest and presumably simplest to build.

I tend to agree this is the most likely choice.

The 2 remaining vehicles are likely to continue development regardless, so it's win-win for NASA. They get the one they throw money at, then the others get made anyway, and when demonstrated, they can use those, too.

[jinnantonix]

42 minutes ago, Nightside said:

As long as it can launch on an existing rocket, like Delta IV Heavy, or Atlas its a safe bet. They are partnered with ULA, so it seems likely. Hopefully their Vulcan will be live-long-and-prospering by then, but better not to count on it.

My next simulation for Artemis 3 will be Dynetics lander on a Vulcan with Centaur, via NRHO Orion rendezvous (no Gateway)  I think this is by far the most likely solution for a 2024 landing.  Vulcan appears to be on track for 2024.  Or have I missed something?

[ndiver]

NASA report on the 3 selected propositions with strengths / weaknesses : https://beta.sam.gov/api/prod/opps/v3/opportunities/resources/files/3488c1f1556745cb87c046135d8ffe00/download?api_key=null&token=

And this article: https://spaceflightnow.com/2020/05/01/nasa-identifies-risks-in-spacexs-starship-lunar-lander-proposal/

[sh1pman]

15 hours ago, tater said:

I tend to agree this is the most likely choice.

Also, Dynetics is based in AL, so the choice is almost certain.

[tater]

1 hour ago, sh1pman said:

Also, Dynetics is based in AL, so the choice is almost certain.

So far the House doesn't like these selections (guess the steamer trunks of money from Boeing arrived), but yeah.

SN got stiffed on commercial crew, so I like them getting some of this (it was important to make sure that one of the 2 commercial crew providers could get everything right the first time, even if they were grossly more expensive, don't you know).

[Barzon]

 

[RCgothic]

I suppose Orion could also dock into a port opposite the lift. That way there's one airlock level with the crew compartment above.

[jinnantonix]

Scott Manley's view https://www.youtube.com/watch?v=_t6pLNEXh18 .  Scott favours Blue Origin, not sure why.
Marcus House's view with a SpaceX slant:  https://youtu.be/MAQeI_h5P8U

Here are a few of my humble opinions on this:
What is NASA's modus operandi for decision-making?  NASA is going to be watching the dollars, and risk.  So they will favour designs which utilise re-usability (to save money long-term), but will look for simplicity short-term.  All of the landers have some level of re-usability conceptually, although SpaceX seems to have this covered best.  NASA will also be looking for simplicity, lower risk, and here I think Dynetics have the best concept, and Blue Origin looks like a loser - 3 parts to be assembled in lunar orbit is complex.  NASA also likes the idea of testing, and BO and SpaceX have both committed to sending descents stages to the surface.  Finally NASA will want to ensure that the R&D investments of contractors are rewarded to some degree to ensure viable long-term competition between commercial operators, in a nutshell they will want to be fair.

Here is my guess on how this will play out:
The 2024 landing will be awarded to Dynetics, as they will represent the lowest cost, lowest risk, for a fully expendable craft.  The question is - will they do a fully autonomous test landing prior to the manned landing, and I think they will have to - will this delay the crewed landing?  I don't believe Dynetics will ever be implemented with re-usability, as this will add complexity and cost - Dynetics are best positioned for low cost, and fully expendable.
By 2024, both Blue Origin and SpaceX will have completed tests with fully autonomous landings on the lunar surface.  Based on these tests, I believe NASA will award the lunar payload contract.  Here is where I think Blue Origin and Draper may be selected, which sets them on a path for Earth and Moon orbit cargo delivery contracts, ultimately using the New Glenn launch vehicle.  
In the short-term SpaceX won;t be ready, they have a lot of work to do on (for example) decent RCS thrusters and crew rating.  Longer term, SpaceX will likely demonstrate full re-usability (and associated cost effectiveness) through implementing their full "Starship ecosystem" of craft (Super Heavy, Starship and the lander) and also proven crew capability, and so when fully developed later in the decade, may take over from Dynetics for the latter part of the Artemis program, as well as compete with BO for payload contracts.  Ultimately they will have the ability to deliver both crew and payload to the lunar surface.  In the short-term they will still win contract for commercial launches eg for Gateway components.
If the above thinking is correct, in addition to to Boeing, the National Team members Lockheed and Northrup Grumman will lose out on HLS.  However NASA can still claim to have been fair on their awarding of contracts:  Boeing has SLS.  Lockheed has Orion.  NG has a number of NASA contracts, like the James Webb Space Telescope and Dawn asteroid explorer.

So what do we all think? 

 

 

 

Edited May 5, 2020 by jinnantonix

[jinnantonix]

Dynetics have the option of assembling the drop tanks in orbit.  Anybody have any idea exactly how this would be done?

[sevenperforce]

2 hours ago, jinnantonix said:

Dynetics have the option of assembling the drop tanks in orbit.  Anybody have any idea exactly how this would be done?

There are two ways to go about it, I suppose. Are the inboard tanks also droppable? If so, it's very straightforward. A new outboard tank is mounted to a new inboard tank on Earth (with sacrificial/expendable decouplers) and both are stacked on a Vulcan Centaur Heavy, which can send 7-8 tonnes direct to NRHO. The inboard tank interfaces with the lander via a docking port connection, so the lander (which has been loitering in NRHO since dropping astronauts off at Orion) uses whatever residuals it has to rendezvous with Centaur. It drops the tank on one side and then uses residuals from the tank on the other side to dock. Repeat with another Vulcan Centaur Heavy, and you're good to go.

If the inboard tanks are permanent, then the docking connection is between the inboard and outboard tanks, and you need prop transfer from a dedicated refill launch. Challenging because you need to transfer fuel, oxidizer, and pressurant. Of course we don't know the engine cycle of the Dynetics lander yet. With those giant solar panels, an electrically-turbopumped methalox lander would be a good choice. Also simplifies prop transfer because you don't need pressurant or high-pressure fluid transfer.

The whole thing really is an extraordinarily Kerballed solution.

I'm assuming that the lander uses more than 7-8 tonnes of propellant per sortie, but if not then the whole refill operation could be done from a single Vulcan launch.

[jinnantonix]

50 minutes ago, sevenperforce said:

There are two ways to go about it, I suppose. Are the inboard tanks also droppable? If so, it's very straightforward. A new outboard tank is mounted to a new inboard tank on Earth (with sacrificial/expendable decouplers) and both are stacked on a Vulcan Centaur Heavy, which can send 7-8 tonnes direct to NRHO. The inboard tank interfaces with the lander via a docking port connection, so the lander (which has been loitering in NRHO since dropping astronauts off at Orion) uses whatever residuals it has to rendezvous with Centaur. It drops the tank on one side and then uses residuals from the tank on the other side to dock. Repeat with another Vulcan Centaur Heavy, and you're good to go.

If the inboard tanks are permanent, then the docking connection is between the inboard and outboard tanks, and you need prop transfer from a dedicated refill launch. Challenging because you need to transfer fuel, oxidizer, and pressurant. Of course we don't know the engine cycle of the Dynetics lander yet. With those giant solar panels, an electrically-turbopumped methalox lander would be a good choice. Also simplifies prop transfer because you don't need pressurant or high-pressure fluid transfer.

The whole thing really is an extraordinarily Kerballed solution.

I'm assuming that the lander uses more than 7-8 tonnes of propellant per sortie, but if not then the whole refill operation could be done from a single Vulcan launch.

I am not so concerned with re-usability, I am assuming for the 2024 mission, the lander will be expendable.  I am more concerned about how to deliver the craft to NRHO with currently available launch vehicles (or expected to be available in 2024).  I am assuming here that there is no fuel transfer, that NASA really does not have the ability in the short-term to develop that capability for the HLS.  I am assuming simplicity -  the lander inner tanks are fixed, and only the outer tanks are dropped.

Below is my simulation under development in RSS.  Mass of total craft at launch is just under 32 tons , with the mass of the craft divided near equally between the lunar descent/ascent craft (15t) , and the two drop tanks with fuel for the transit from TLI to NRHO to LLO ( 17t). 

Launching the fully fueled two stage Dynetics lander craft to LEO is beyond the single launch capability of the Vulcan Centaur Heavy (max payload to LEO = 27.2 tons).  Only SLS Cargo and Falcon Heavy can lift the assembled craft to LEO.

Options:

1. Multiple Vulcan launches ( two or three) with assembly adding drop tanks in LEO and docking with a Centaur second stage for TLI -  high risk, cost and complexity. 
2. Single launch of the fully integrated craft on a SpaceX Falcon Heavy to LEO, dock with separate launch of Falcon 9 or Vulcan Centaur second stage for TLI.   Simpler LEO docking?  
3. SLS Block 1B Cargo, single launch to NRHO.  EUS?  Too expensive?  Available in 2024?

Edited May 6, 2020 by jinnantonix