Question about Human Landing System

[Involute]

Newb here.  As I understand it, the mission profile for an Artemis moon mission involves using SLS to send astronauts to the Gateway in an Orion.  A Human Landing System (modified Starship) will be waiting there, after having been topped off in LEO by multiple Starship refuelings.  The astronauts transfer to the HLS and descend to the moon.  They return in the HLS, transfer to Orion, and return to Earth.

What happens to the HLS?  Even if it arrives at the Gateway with enough fuel for multiple Gateway-moon-Gateway trips, eventually it will run out of gas.  Is there a plan to send one or more Starships from Earth to refuel it?  Or a topped off HLS to replace it (so the first gets abandoned)?  Am I misunderstanding the mission profile?

Thanks for any clarification.

[punder]

I’ve been here a while and would like to hear this explained as well!

But my general impression, as a mere poorly informed enthusiast, is that NASA has no firm ideas past Artemis III for HLS reuse, and that for Artemis III the lander is simply abandoned. But I could be totally wrong.

Welcome!

Edit, or Artemis IV. At the moment I forget which is the first crewed landing.

[DanClemmensen]

Newb here.  As I understand it, the mission profile for an Artemis moon mission involves using SLS to send astronauts to the Gateway in an Orion.  A Human Landing System (modified Starship) will be waiting there, after having been topped off in LEO by multiple Starship refuelings.  The astronauts transfer to the HLS and descend to the moon.  They return in the HLS, transfer to Orion, and return to Earth.

What happens to the HLS?  Even if it arrives at the Gateway with enough fuel for multiple Gateway-moon-Gateway trips, eventually it will run out of gas.  Is there a plan to send one or more Starships from Earth to refuel it?  Or a topped off HLS to replace it (so the first gets abandoned)?  Am I misunderstanding the mission profile?

Thanks for any clarification.

SpaceX is contracted to NASA to provide the HLS service as you described it. the HLS remains SpaceX's property and they can do what they want with it after that: it's not part of the contract. There are actually two HLSs: the uncrewed demo that flies prior to Artemis III, and then the actual Artemis III HLS. (Note, we don't know that depot is in LEO. it might be in a higher EO).

We do not know what SpaceX will do with those HLSs. I personally don't think are will be permitted to simply abandon them in NRHO, so at a minimum they must be disposed of, probably by crashing into the Moon.

Attempting to refuel HLS in NRHO is a major undertaking, requiring a multiple tanker flights. To get a tanker to NRHO, you start by sending multiple tankers to the depot in EO, and then send one tanker (or possibly the depot) to NRHO with enough fuel to get itself plus HLS back to EO.

[DanClemmensen]

I’ve been here a while and would like to hear this explained as well!

But my general impression, as a mere poorly informed enthusiast, is that NASA has no firm ideas past Artemis III for HLS reuse, and that for Artemis III the lander is simply abandoned. But I could be totally wrong.

Welcome!

Edit, or Artemis IV. At the moment I forget which is the first crewed landing.

NASA has fairly firm plans for the follow-on HLS, which is referred to as the "sustainable" HLS. the plan calls for competition, but realistically the only candidate for the second crewed landing is a new versio of Starship HLS. Therefore, NASA will excersize "Option B" of the existing HLS contract with SpaceX to acquire this "sustainable" version of Starship HLS. NASA will also get competitive bids under "Appendix P" of the NextSTEP program from multiple companies for their "sustainable" HLSs. These HLSs will compete with the sustainable Starship HLS for landings after the first two.

I know that NASA has announced these plans. I do not know if Congress will fund them, but Congress pretty much mandated the whole "appendix P" thing.

[StarshipTrooper]

It seems that after completing their contract, either of the HLS vehicles would be a useful resource with all the huge amount of living and storage space. They could have great utility attached to the Gateway, in lunar orbit, or even returned to the surface of the moon.

[yg1968]

Newb here.  As I understand it, the mission profile for an Artemis moon mission involves using SLS to send astronauts to the Gateway in an Orion.  A Human Landing System (modified Starship) will be waiting there, after having been topped off in LEO by multiple Starship refuelings.  The astronauts transfer to the HLS and descend to the moon.  They return in the HLS, transfer to Orion, and return to Earth.

What happens to the HLS?  Even if it arrives at the Gateway with enough fuel for multiple Gateway-moon-Gateway trips, eventually it will run out of gas.  Is there a plan to send one or more Starships from Earth to refuel it?  Or a topped off HLS to replace it (so the first gets abandoned)?  Am I misunderstanding the mission profile?

Thanks for any clarification.

SpaceX's hasn't been clear about this. SpaceX has said that Starship would be refueled in Earth orbit. It's not clear what Earth orbit means in the circumstances, it might not be LEO.

[VSECOTSPE]

Everyone else has covered the question.  But I’ll just point out that there’s a Missions to the Moon board (scroll down a bit from this Orion one) where there’s lots more of this lander stuff.

[DanClemmensen]

It seems that after completing their contract, either of the HLS vehicles would be a useful resource with all the huge amount of living and storage space. They could have great utility attached to the Gateway, in lunar orbit, or even returned to the surface of the moon.

Perhaps true in the abstract. However, NASA is paying SpaceX $2.89 million dollars to provide a specific service with specific requirements, and SpaceX as a for-profit commercial company has little incentive to add capabilities to do stuff that is not in the contract, such as landing on the Moon after the end of the mission and sustaining itself in some sort of usable condition for months or years on the lunar surface, or acting as part of Gateway.  The first two HLSs will be in NRHO prior to the arrival of the first two Gateway modules (PPE and HALO) and would need to sustain themselves until its arrival. Gateway probably does not have sufficient docking capacity for those two HLSs in addition to its other customers (Orion, Dragon XL, the next HLS), and HLS is HUGE compared to the rest of Gateway, which may be a technical challenge and is certainly a political embarrassment.

Starship HLS will vastly exceed the HLS contract requirements, but SpaceX did this to save money, not to provide freebies to NASA. The cheapest way to meet NASA's requirements was to adapt Starship, and that resulted in the extra capabilities.

[yg1968]

The post by Woods170 below is relevant to the original poster's question:

https://ntrs.nasa.gov/api/citations/20220003725/downloads/22%203%207%20Kent%20IEEE%20paper.pdf

From that image, it doesn't look like the Propellant Starship is coming back to Earth. I guess that it can stay in Earth orbit and be used more than once.

Depot ship stays in Earth orbit and is to be used for BOTH missions (uncrewed demo mission and the crewed landing).

On a further note: some SpaceX personnel informally refer to the depot ship as "the Shelby", in an obvious stab at a certain senator.

[eric z]

  Since no one else seems to want to, I will volunteer to take the plunge! What have we gotten ourselves into? Am I the only one here who thinks this "Program", and I use that term loosely, is completely ridiculous? Rockets that don't exist.
Rockets that maybe only fly once a year. Years between flights. Massive refueling operations in space - must be simple, they do it in the movies!
  Let's play spin-the-bottle to decide whose space suit to use. Let's junk the "Commercial" capsules we just developed, they don't fit the "architecture". Oh yeah, we need a new "commercial"space station while we're at it, but we will have a baby station in lunar orbit for astronauts to chill and have a beer as they roast in radiation on their way down to the moon base - oh wait, there is no moon base.
 
 I wanted to live at least long enough to see us back on the moon, for good, but I am getting quite pessimistic, sorry!

[yg1968]

  Since no one else seems to want to, I will volunteer to take the plunge! What have we gotten ourselves into? Am I the only one here who thinks this "Program", and I use that term loosely, is completely ridiculous? Rockets that don't exist.
Rockets that maybe only fly once a year. Years between flights. Massive refueling operations in space - must be simple, they do it in the movies!
  Let's play spin-the-bottle to decide whose space suit to use. Let's junk the "Commercial" capsules we just developed, they don't fit the "architecture". Oh yeah, we need a new "commercial"space station while we're at it, but we will have a baby station in lunar orbit for astronauts to chill and have a beer as they roast in radiation on their way down to the moon base - oh wait, there is no moon base.
 
 I wanted to live at least long enough to see us back on the moon, for good, but I am getting quite pessimistic, sorry!

That's a very negative way of seeing things.

Commercial crew capsules will be used for the Commercial LEO Destinations program. NASA is not giving up on LEO.

In terms of SLS, yes once a year is not enough but the development of HLS-Starship and Starship gives me hope that a commercial alternative to SLS will exist in a few years. Hopefully, NASA will take advantage of it once it is operational. 

NASA's plans is to eventually have a commercial lunar destinations program. These plans are for the late 2030s but I suspect that these plans will be accelerated once Starship is operational. NASA's current plan is to have a lunar base camp with only one habitat but eventually in the late 2030s to use commercial lunar habitats.

[punder]

  Since no one else seems to want to, I will volunteer to take the plunge! What have we gotten ourselves into? Am I the only one here who thinks this "Program", and I use that term loosely, is completely ridiculous? Rockets that don't exist.
Rockets that maybe only fly once a year. Years between flights. Massive refueling operations in space - must be simple, they do it in the movies!
  Let's play spin-the-bottle to decide whose space suit to use. Let's junk the "Commercial" capsules we just developed, they don't fit the "architecture". Oh yeah, we need a new "commercial"space station while we're at it, but we will have a baby station in lunar orbit for astronauts to chill and have a beer as they roast in radiation on their way down to the moon base - oh wait, there is no moon base.
 
 I wanted to live at least long enough to see us back on the moon, for good, but I am getting quite pessimistic, sorry!

You are not alone.

[TrevorMonty]

Newb here.  As I understand it, the mission profile for an Artemis moon mission involves using SLS to send astronauts to the Gateway in an Orion.  A Human Landing System (modified Starship) will be waiting there, after having been topped off in LEO by multiple Starship refuelings.  The astronauts transfer to the HLS and descend to the moon.  They return in the HLS, transfer to Orion, and return to Earth.

What happens to the HLS?  Even if it arrives at the Gateway with enough fuel for multiple Gateway-moon-Gateway trips, eventually it will run out of gas.  Is there a plan to send one or more Starships from Earth to refuel it?  Or a topped off HLS to replace it (so the first gets abandoned)?  Am I misunderstanding the mission profile?

Thanks for any clarification.

Attempting to refuel HLS in NRHO is a major undertaking, requiring a multiple tanker flights. To get a tanker to NRHO, you start by sending multiple tankers to the depot in EO, and then send one tanker (or possibly the depot) to NRHO with enough fuel to get itself plus HLS back to EO.

Refuelling HLS in NRHO is relatively straightforward and cheaper than replacing it. Use a disposable tanker that is topped up in EO. Tankers are cheap and light weight as there is no heatshield or need for landing engines.

HLS will need its life support consumerables replaced by next crew. Cargo vehicle or Orion could transport these consumerables to Gateway.

[punder]

Thanks for any clarification.

Ha ha! I think I speak for all of us when I say “You’re welcome.”

/s 

[DanClemmensen]

Newb here.  As I understand it, the mission profile for an Artemis moon mission involves using SLS to send astronauts to the Gateway in an Orion.  A Human Landing System (modified Starship) will be waiting there, after having been topped off in LEO by multiple Starship refuelings.  The astronauts transfer to the HLS and descend to the moon.  They return in the HLS, transfer to Orion, and return to Earth.

What happens to the HLS?  Even if it arrives at the Gateway with enough fuel for multiple Gateway-moon-Gateway trips, eventually it will run out of gas.  Is there a plan to send one or more Starships from Earth to refuel it?  Or a topped off HLS to replace it (so the first gets abandoned)?  Am I misunderstanding the mission profile?

Thanks for any clarification.

Attempting to refuel HLS in NRHO is a major undertaking, requiring a multiple tanker flights. To get a tanker to NRHO, you start by sending multiple tankers to the depot in EO, and then send one tanker (or possibly the depot) to NRHO with enough fuel to get itself plus HLS back to EO.

Refuelling HLS in NRHO is relatively straightforward and cheaper than replacing it. Use a disposable tanker that is topped up in EO. Tankers are cheap and light weight as there is no heatshield or need for landing engines.

HLS will need its life support consumerables replaced by next crew. Cargo vehicle or Orion could transport these consumerables to Gateway.

The incremental cost of a replacement HLS instead of a disposable tanker is low, and you end up with a fully-provisioned and updated HLS, and no need to figure out how to transfer propellant from a tanker to an HLS. There is no such need in the nominal HLS mission: fuel transfers from tankers to depot and then from depot to HLS, not from tanker to HLS, and we do not know how it will be done.

[TrevorMonty]

Newb here.  As I understand it, the mission profile for an Artemis moon mission involves using SLS to send astronauts to the Gateway in an Orion.  A Human Landing System (modified Starship) will be waiting there, after having been topped off in LEO by multiple Starship refuelings.  The astronauts transfer to the HLS and descend to the moon.  They return in the HLS, transfer to Orion, and return to Earth.

What happens to the HLS?  Even if it arrives at the Gateway with enough fuel for multiple Gateway-moon-Gateway trips, eventually it will run out of gas.  Is there a plan to send one or more Starships from Earth to refuel it?  Or a topped off HLS to replace it (so the first gets abandoned)?  Am I misunderstanding the mission profile?

Thanks for any clarification.

Attempting to refuel HLS in NRHO is a major undertaking, requiring a multiple tanker flights. To get a tanker to NRHO, you start by sending multiple tankers to the depot in EO, and then send one tanker (or possibly the depot) to NRHO with enough fuel to get itself plus HLS back to EO.

Refuelling HLS in NRHO is relatively straightforward and cheaper than replacing it. Use a disposable tanker that is topped up in EO. Tankers are cheap and light weight as there is no heatshield or need for landing engines.

HLS will need its life support consumerables replaced by next crew. Cargo vehicle or Orion could transport these consumerables to Gateway.

The incremental cost of a replacement HLS instead of a disposable tanker is low, and you end up with a fully-provisioned and updated HLS, and no need to figure out how to transfer propellant from a tanker to an HLS. There is no such need in the nominal HLS mission: fuel transfers from tankers to depot and then from depot to HLS, not from tanker to HLS, and we do not know how it will be done.

Tanker, SS, depot or HLS they will all use the fuel transfer system. The HLS has to be top up on its maiden mission so why would it be any different 2nd time round.

[DanClemmensen]

Newb here.  As I understand it, the mission profile for an Artemis moon mission involves using SLS to send astronauts to the Gateway in an Orion.  A Human Landing System (modified Starship) will be waiting there, after having been topped off in LEO by multiple Starship refuelings.  The astronauts transfer to the HLS and descend to the moon.  They return in the HLS, transfer to Orion, and return to Earth.

What happens to the HLS?  Even if it arrives at the Gateway with enough fuel for multiple Gateway-moon-Gateway trips, eventually it will run out of gas.  Is there a plan to send one or more Starships from Earth to refuel it?  Or a topped off HLS to replace it (so the first gets abandoned)?  Am I misunderstanding the mission profile?

Thanks for any clarification.

Attempting to refuel HLS in NRHO is a major undertaking, requiring a multiple tanker flights. To get a tanker to NRHO, you start by sending multiple tankers to the depot in EO, and then send one tanker (or possibly the depot) to NRHO with enough fuel to get itself plus HLS back to EO.

Refuelling HLS in NRHO is relatively straightforward and cheaper than replacing it. Use a disposable tanker that is topped up in EO. Tankers are cheap and light weight as there is no heatshield or need for landing engines.

HLS will need its life support consumerables replaced by next crew. Cargo vehicle or Orion could transport these consumerables to Gateway.

The incremental cost of a replacement HLS instead of a disposable tanker is low, and you end up with a fully-provisioned and updated HLS, and no need to figure out how to transfer propellant from a tanker to an HLS. There is no such need in the nominal HLS mission: fuel transfers from tankers to depot and then from depot to HLS, not from tanker to HLS, and we do not know how it will be done.

Tanker, SS, depot or HLS they will all use the fuel transfer system. The HLS has to be top up on its maiden mission so why would it be any different 2nd time round.

We do not know that the refuelling connections are symmetrical. We know that a tanker can connect to a depot, and we know an HLS  can connect to a depot. We do not know that a tanker can connect to an HLS. It's possible, and even reasonable that the depot is the only Starship that can connect to other Starships for fuel transfer. There is an extensive thread discussing in-orbit refuelling:
   https://forum.nasaspaceflight.com/index.php?topic=50157.0
If this is true and if you want to refuel HLS in NRHO, then you will need to send Depot to NHRO to do that. Sending Depot on an out-and-back to NRHO is feasible, but the entire mission will take quite a few tanker flights.

[deadman1204]

The "disposable tanker" in lunar orbit will still be a FULL ROCKET getting thrown away. The only difference will be refueling hardware instead of a human compartment.

[TheRadicalModerate]

Refuelling HLS in NRHO is relatively straightforward and cheaper than replacing it. Use a disposable tanker that is topped up in EO. Tankers are cheap and light weight as there is no heatshield or need for landing engines.

You don't need a disposable tanker when you take prop from LEO to NRHO.  Two potential conops:

1) Use a regular lift tanker, filled from the LEO depot, to take the prop to another depot in NRHO.  Then the lift tanker (which is capable of EDL) can return direct to EDL from cislunar space.

2) Use the lift tanker to refuel the Lunar Starship directly, with no depot at all in cislunar, after which it returns to EDL.

Option #1 requires a second depot, but only one depot for an indefinite number of missions.  Option #2 is more parsimonious in terms of hardware, but it requires that the LSS be able to manage boiloff for an extended period of time, until the Orion shows up.  However, I think that's probably a requirement to get Option A to work in the first place.

[TheRadicalModerate]

If this is true and if you want to refuel HLS in NRHO, then you will need to send Depot to NHRO to do that. Sending Depot on an out-and-back to NRHO is feasible, but the entire mission will take quite a few tanker flights.

But once the depot is in NRHO, it can be fueled via lift tankers, which can then return direct to EDL. (I'm assuming that the TPS will be engineered to support EDL from translunar.)  So, even if depots can't do EDL, you only need two, and everything else carrying prop is a lift tanker, which is reusable.