jinnantonix

I am thinking that is the least of problems. I also think the LED and camera technology has improved enough to overcome the issue.

No, the whole point of the crater is that it is thought to contain millions of tons of recoverable raw materials for fuel manufacture. It may be unpopular, but nuclear power is needed to research and establish the manufacturing of those fuels.

Here is a model of the two stage lander, This was simulated successfully and has just enough dV to launch from the LOP-G, land on the lunar surface and return to the LOP-G. The ascent vehicle comprises of a 3.5t Orion pressure vessel with RTG (yes, it needs RTG), ladder, and is assumed to have a mass of 4.0t. It uses 4 x AJ10-190 engines at ISP = 316 (vac), assumes 2+2 redundancy, which tests really well. The craft weighs just under 16t fully fueled so theoretically can be launched to TLI by a Falcon Heavy. The expendable transit vehicle is just a big hypergolic fuel tank with a tight cluster of 3 x SuperDRAC engines. It has a mass of 28t fully fueled, but could be launched partially fueled on a Falcon Heavy. I have assumed both craft expend dV ~ 800m/s for rendezvous with LOP-G. The problem is that it actually takes two launches of a partially fueled transit vehicle on a Falcon Heavy along with docking and fuel transfer at the LOP-G to ready the craft for transit from LOP-G to lunar surface and return to LOP-G. So to complete just one crewed lunar surface mission requires 4 x launches of the Falcon Heavy, plus crewed launch of the SLS/Orion. Ouch. At this point, I am thinking that using a 3.5t Orion pressure vessel is not going to work and that a purpose built and much smaller 2-man lunar lander is needed if the proposed two stage lander is going to succeed as part of the Artemis program. Have you seen the sides of Shackleton Crater? Way too steep for a rover. I read somewhere that there was a proposal to power ISRU in the crater by positioning automated mirror reflectors on the crater rim. Feasible I suppose, but the setup would be costly and expensive, and prone to reliability issues that could spell disaster. OTOH, use a RTG.

Posted 27 minutes ago (edited) Link please. LOP-G in NRHO is to ensure access to the south pole. Landing at the south pole is to investigate the availability of water ice for manufacturing fuel. This ice is ONLY located in quantity in the permanent darkness of the crater floor. Landing on the rim does not meet the mission objectives. Obviously. Correct, but that is just the first phase. Of course humans are not going to be landed in Shackleton Crater without an accurate robotic survey and robotic testing of a full scale craft. I am agreeing with comments that state that 2024 for first crewed landing is not possible, a successful uncrewed landing must be completed first.

Wrong. That's why NASA is contracting out to get low cost, light weight science payloads there first. The surface will be accurately mapped and modeled, and landing sites will be picked out. The landing of anything in Shackleton Crater will be automated and will not rely on visuals.

SpaceX and Blue Origin are a long way from getting their respective large launch vehicles to orbit, let alone getting fully approved human rating. Honestly, Starship just looks like a silly PR stunt, who is going to pay for a human rated launch on this craft? Cargo versions of BFR and New Glenn will make SLS obsolete, and the sooner that happens the better. It won't be for at least 5-10 years, so at best will engage at Artemis 4. While the Artemis Program lunar lander construction is contracted, NASA is still be under-writing the human rating. I think this issue not given the weight it deserves, and remains the main reason why I believe NASA and SLS will be the most likely to get humans to the moon first. Then the crew will freeze and suffocate on the floor of Shackleton Crater.

@sevenperforce I like your idea, attractive in it's simplicity. The AV loses some efficiency by needing to carry around ladders and landing legs. This to be balanced around not needing the equipment for undocking the AV from the DV at lunar launch. Also, any excess weight, logistics packaging, science instruments, etc would need to be manually dropped from the AV prior to launch. Assuming the AV is re-usable, what engine configuration would you use? I would suggest an array of 4 engines with N+1 redundancy. Modified RL10 or AJ10-190 plus an array of hypergolic thrusters for fine tuning would seem suitable. I am not sure of the re-usability of RL10s? I would suggest the transfer vehicle would use SuperDraco's plus DRACO docking thrusters as it will only need to fire main engines twice, first during insertion into NRHO, then to de-orbit the AV. Delivery would require two Falcon Heavy launches (would this give SpaceX a monopoly?). The Orion with crew launched on a SLS Block 1B. Probably the refuelling could be delivered using a Cygnus piggybacking on the SLS? Or at worst a third commercial launch on a Vulcan or Falcon 9. The Cygnus would need to be beefed up for the insertion into NRHO.

From what I can tell, the intention is for the crew to survey the lunar surface for minerals, water and organic compounds suitable for manufacturing fuel, and to test the surface to allow the design of an ISRU facility. They would need to take a lot of instruments for in situ collection of data, of course the instruments will all be left behind. Regarding the Lockheed Martin design, I think the Orion pressure vessel is unnecessarily large. Lunar missions really only need two crew, and basic facilities for a two week stay. On the other hand, the pressure vessel I am using in my model is tiny, only 1.8m diameter and 2.3 m in length, weighing 1.1t. , not a realistic size for two crew, it would need to be at least double the volume and mass.

@sevenperforce the model of the Ascent Vehicle in my simulation had a wet mass of 3.64t, excluding payload and LS resources. It is capable of launching from the surface to the LOP-G. It uses a pair of AJ10-190 hypergolic fuelled engines.

You make that sound like a bad thing. Had you considered that the more the SLS/Orion and LOP-G is suited to a specific mission, the less suitable it is for others. My understanding is that NRHO was chosen because the location could be a staging post for non-lunar missions, such as deep space probes to asteroids or repairing space probes located in heliocentric orbit, or Mars. Why would you want to burn all the way to LLO if not going to the moon? If there really is an ability to manufacture fuel on the moon, surely it is more cost effective to position the refuelling station in HLO or at a Lagrange point. I have no link, I believe an RTG is required because in my simulation it is not possible to land in Shackleton Crater and do anything there without RTG. In fact by my reckoning the entire mission to the lunar south pole can and should be done with RTG only and no solar panels. I am talking about the Artemis Program, the subject of this thread. No, actually it's not. Yes, actually it is. Look up the meaning of the word "variant". And what have you got against the SRBs? Seems to me to be a simple and cost effective solution to a difficult problem. Sure there are alternatives, but how long would NASA need to prove the technology, and how much would it cost? I suspect this is why the option of an in-transit rendezvous at LOP-G ( and maybe also a RTG) is excluded from the initial spec for the lunar lander. They may wish to just get an uncrewed test craft to the surface at an equatorial location, in order to test more challenging aspects of the craft and mission, e.g. docking with the transit vehicle, multiple firing of the ascent and transit vehicle engines, and docking the ascent craft at LOP-G. I maintain however that the successful completion of the Artemis program, which specifies landing at the lunar south pole, will require the lunar lander to meet the Orion at LOP-G for crew transfer, and it will require a RTG.

Having completed a simulation of the Artemis program I have a qualitative impression of the capability of Orion for the requirements of the program. The capsule itself is relatively heavy, but that is to be expected because the craft is big and roomy (compared to Apollo) and it needs to be robust enough for re-usability, and have features that support a crew of 4-6 for periods of 21 days (or more). The outcome of a heavy capsule, is that the SM has a lot of mass to push around, and that is going to limit Orions range. The SM also has some constraints: Firstly it has a lot of redundancy to satisfy human rating requirements, it needs facilities to provide for safely carrying resources for a long mission, and it needs to be cost effective (since it is fully expendable). To meet these constraints, it is not surprising the SM does not have a huge delta-V capability, it is enough to get to NRHO or lunar DRO and return, that is what it is designed for and it does that well, and with a reasonable design factor built in. Get humans to high lunar orbit, and bring them back safely. Tick. It has always been assumed that a large part of the heavy lifting would be done on non-human rated, commercial carriers. Hence the idea that there be a staging post in HLO where crew would transfer from Orion to very carefully built and fully tested facilities for lunar landing (2 crew) and return to HLO. The challenge being presented now to contractors is substantial - to build a human rated craft capable of 2 weeks on the lunar surface, to travel from HLO to surface and return, and to be powered and heated at least partially by RTG (yes, this will be a requirement). This is a much bigger design problem than faced by Grumman Aircraft in building Apollo's LEM. NASA's SLS will work (it's just a variant of the Space Shuttle technology), and commercial carriers like SpaceX with Falcon 9 and Falcon Heavy, and ULM Vulcan can lift the cargo reliably and cost effectively. In my opinion the whole plan for a 2024 landing rests on successfully proving the design of a human rated lunar lander that can reach HLO unmanned, and then complete a manned landing and return to HLO. If it is re-usable in any way will be a bonus. If it is cost effective enough to meet the requirements of the Artemis program, I will be amazed.

Nuclear engines (NTERs) provide an excellent solution for powering a re-usable tug for moving payloads from LEO and lunar surface to lunar orbit, asteroid research and even Mars. They can use hydrogen or methane propellant for initial burn from Earth (utilising the Oberth effect), and potentially use ammonia as it requires smaller, lighter tanks, and remains stable and easy to store without cryogenics for long term flights. Using nuclear power means the craft can visit deep space or in the shadows of planets and moons since not reliant on solar power. A nuclear tug without the need for angling solar panels can more easily spin to create artificial gravity. If NASA is successful in establishing mining on on the moon, nuclear electric power generation will be required to power the mining, milling and enrichment process, and nuclear tugs offer a good solution for launching the fuel to lunar orbit and beyond.

I do think it is feasible to integrate the mining, milling, enrichment/processing and storage of fuels in a single launch unit, which roves the surface dropping spoil as it goes, and which docks directly with the space tugs to refuel them. The rate at which a unit can produce fuel is an issue, especially with no solar power, and I would argue this may possibly be resolved by having many units. Technically doable, but is this commercially viable? I doubt it.

All good questions @Geschosskopf. I think the problem is that we don't yet understand the resources that are available, all planning stems from that knowledge. We need to get to Shackleton Crater and find out - I would argue that Peregrine Lander should already be making plans. Whatever the ultimate design of the ISRU facility, it is going to be a remarkable engineering feat. I don't see tradesmen ever setting foot on the moon - all equipment will built on Earth to operate autonomously. Whilst my roving robotic nuclear powered ISRU rig is a somewhat simplistic model, the ultimate solution cannot be too far from that concept, or the whole endeavour will be commercially non-viable, and launch from LEO will again be the preferred method for deep space exploration.

What type of craft will be used? Below is the nuclear tug concept. The three NERVA engines are arranged in a redundant N+1 configuration, on gimbal base so if one engine fails the others supply sufficient balanced thrust to make lunar orbit. The craft refuels on the lunar surface from the South Pole ISRU facility, and consumes about 40% of the lower tank hydrogen fuel mass in achieving NRHO. The craft then as sufficient dV to transport a habitation module with spin gravity from lunar NRHO to Mars orbit. The upper tank contains sufficient ammonia propellant to return to lunar NRHO. There will be two or three tugs operating to provide payload delivery to local asteroids, comets, Mars and Venus.

At the completion of the Artemis program, NASA will have a functioning Lunar Orbital Platform - Gateway in NRHO (near rectilinear halo orbit) around the Moon. This simulation suggests that the best case outcome of the program is the deployment of a functioning ISRU facility at the Moon's South Pole. What type of resource will ISRU be based on? Water ice can be converted into hydrogen and oxygen. If there are carbon compounds available, methane may be a possible fuel. If there is nitrogen, perhaps ammonia, a very useful propellant for for NERVA engines as it is very stable, and unlike hydrogen and methane does not need costly cryogenics, and does not boil off over time. Would it be feasible to manufacture hypergolic fuels, such as Aerozine/NTN? All these options will require a lot of energy, and this cannot be provided by solar power in the darkness of the south pole. Is it feasible to deploy nuclear power, sufficient to manufacture fuel at a suitable rate? What type of craft will be used? Assuming fuel is manufactured on the lunar surface, NASA would need to contract for development of suitable craft to use the fuel. I envisage the development of highly efficient re-usable nuclear tugs with ISP >800. These craft would utilise nuclear fuel for energy, possibly with NERVA engines (a well proven technology), and using lunar manufactured propellant (hydrogen, methane or ammonia). They could be used for lifting payloads from LEO to lunar orbit, or for any number of deep space exploration needs, including ferrying payloads such as rovers and even humans to Mars orbit. The craft would be re-usable, and only require occasional re-fuelling with nuclear fuel, most likely in LEO. These craft would be capable of landing on the lunar surface for direct refueling from the ISRU facility. A manned mission to Mars? By 2030, it is likely that SpaceX and Blue Origin will be competing for launch contracts with their Falcon Super Heavy and New Glenn rockets. Despite the hype, it seems unlikely that these craft will be human rated, concepts like Starliner seem fanciful from a commercial and safety perspective, and seem to just be a PR exercise. However the ability to lift low cost interplanetary craft to orbit is feasible, and even likely. Such craft would be autonomous, and potentially travel direct to Mars from LEO, or be refuelled in lunar orbit, to deliver surface logistics and redundant re-usable methane powered Martian ferry craft (MAVs) and ISRU facilities on the Martian surface in preparation for human arrival. Human rated equipment would rendezvous via LOP-G and utilise Orion for ferrying to/from the Earth's surface. A craft with spin gravity could dock with nuclear tugs for the trip to/from Mars orbit. The MAVs would be used to ferry humans to/from the Martian surface. By this means, an international effort could potentially land humans on Mars by 2040.

The LTV had just enough fuel to do the job, remember the tank is designed to be big enough to decelerate with fully fueled LAV and LDV 850m/s from TLI to encounter with LOP-G, then have enough fuel for the lunar landing and return. The tank looks small in the video, but it's not small. By fully refilling the tank from a Cygnus resupply module the LTV has just enough dV to get the LSA and lander to LLO (100km alt). See below. It is a done by remote control of the LTV. The only trick is ensuring the ladder on the LDV lines up with the door of the LAV. IRL the Orion crew would probably use the robotic arm to assist, but I didn't need to.

Artemis 8 - Airlock Module and Lunar Surface Asset Deployment 2028 SLS Block 1B Crew Artemis 8 Delivery of Airlock Module and lunar landing of crew and "Asset"

Artemis 8 - Airlock Module and Lunar Surface Asset Deployment 2028 SLS Block 1B Crew Artemis 8 Delivery of Airlock Module and lunar landing of crew and "Asset"

Artemis 8 - Airlock Module and Lunar Surface Asset Deployment 2028 SLS Block 1B Crew Artemis 8 Delivery of Airlock Module and lunar landing of crew and "Asset"

Artemis 8 - Airlock Module and Lunar Surface Asset Deployment 2028 SLS Block 1B Crew Artemis 8 Delivery of Airlock Module and lunar landing of crew and "Asset" The final mission in the Artemis program. This series could not have been done without SSTU.

Artemis 7 - Lunar Surface Asset Delivery to Gateway Features SSTU components in the SLS Block 1B Cargo and lunar landers.

Artemis 7 - Lunar Surface Asset Delivery to Gateway 2028 Falcon Heavy** Artemis 7a Uncrewed delivery of fuel resupply module and lunar descent vehicle 2028 SLS Block 1B Cargo Artemis 7 Delivery of "Lunar Surface Asset" (large lunar surface module) to LOPG

Artemis 7 - Lunar Surface Asset Delivery to Gateway 2028 Falcon Heavy** Artemis 7a Uncrewed delivery of fuel resupply module and lunar descent vehicle 2028 SLS Block 1B Cargo Artemis 7 Delivery of "Lunar Surface Asset" (large lunar surface module) to LOPG

Artemis 7 - Lunar Surface Asset Delivery to Gateway 2028 Falcon Heavy** Artemis 7a Uncrewed delivery of fuel resupply module and lunar descent vehicle 2028 SLS Block 1B Cargo Artemis 7 Delivery of "Lunar Surface Asset" (large lunar surface module) to LOPG