Hacker News Reader

Comment by scottrogowski | Hacker News Reader

I have a genuine curiousity (because I can't seem to find it in the news reports). The contract is going to the starship design. What exactly are they planning to take that requires such a large ship? The lunar landers were tiny because the Moon has such a small gravity well. For that payload capacity, I assume you would have most or all of a habitable lunar base.

Edit: There is this: https://blogs.nasa.gov/artemis/2020/10/28/lunar-living-nasas.... I wonder whether NASA will now try to include it on one of the two missions.

View on HN

> What exactly are they planning to take that requires such a large ship?

NASA didn't ask for such a big ship, and would have accepted a smaller one. But if SpaceX bids a big ship, they can't say "no" to it just because it is bigger than they thought they needed.

For the first few landings they probably won't even use most of the capacity. But I'm sure NASA will get to work coming up with ideas of things to do with it.

One option is to have a much bigger crew.

Another option is cargo such as lunar rovers, lunar base modules, ISRU demonstrators, etc. (I wonder if SpaceX will design a slightly different variant optimised for lunar surface cargo delivery.)

They definitely won’t use most of the capacity because they can’t deliver/return even a tiny percentage of it using star liner!

You mean Orion, not Starliner.

For inbound cargo, they definitely can use it to its full cargo capacity, since the cargo can be launched with it from Earth.

For crew, yes for now the limiting factor is Orion – Orion can only take a crew of four, so that's a maximum number of people you can take onboard, without resorting to multiple flights (infeasible given the cost of the SLS+Orion stack)

However, once Starship is crew-rated for launch and re-entry, the number of possible crew is going to increase – I don't know what the limit is, but at least 10, maybe even 20.

(Orion is initially also a limiting factor for returning cargo. However, they could use a cargo Starship, provided the returning cargo can be transferred to the cargo Starship in lunar orbit. This may happen before crew-rating Starship for launch and re-entry does.)

> However, once Starship is crew-rated for launch and re-entry, the number of possible crew is going to increase – I don't know what the limit is, but at least 10, maybe even 20.

Elon has mentioned Starship carrying 100 people. NASA however, has fewer than 50 astronauts.

That's for Crew Starship. The HLS Starship has a different design and may have less crew capacity. 10-20 is just a guess on my part, I don't know what the actual crew capacity is. But I expect SpaceX to trade-off a lower crew capacity for a bigger cargo capacity, since (at least initially) NASA is going to have a much greater need for cargo to the lunar surface than for crew to the lunar surface.

Also, Musk talks now about a 100 person capacity for Crew Starship, it probably will shrink as the design progresses. The same thing happened to Dragon – it went from 7 seats down to 4 – NASA safety requirements had some role in that, but the same thing might have happened even without NASA.

I think the crew capacity will also depend on the length of the trip. A trip to Mars needs a lot more supplies than a trip to the Moon, and the more supplies you need to take with you, the fewer people you can fit on the ship. This is not supplies for the destination, it is supplies for the journey – a 6 month journey requires 6 months worth of supplies; you can always send separate cargo ships to the destination for supplies you need after you get there. (Unless, you could dock with a cargo ship mid-journey and transfer more supplies over – that would be possible in principle, but probably more complexity than it is worth in practice.)

You’re right, thanks for the starliner/Orion correction!

I think we are all curious about that. NASA didn't plan for this. Its a lucky break that SpaceX 'over-delivered' to an absurd degree.

There must be people inside NASA that are over the moon about this. You can now fly a full geology lab to the surface of the moon. You can take a big rover. You can do all sorts of crazy things.

You can just land one of these on the moon and leave it there as a whole moonbase. One Starship is comparable to ISS.

NASA will have so many options, its gone be interesting to see what they and SpaceX come up with for the interior.

Starship is big because it's meant to do other things. The mission parameters didn't require it.

Reply on news.ycombinator.com