[stetrain]

I think that understanding of the consensus is incorrect. The mission plan for Artemis 3 is that a specialized Starship upper stage will be refueled in LEO and then transfer to lunar orbit where it will wait for astronauts arriving on SLS/Orion.

Yes the mission profile is more complex, but that complexity can mostly be settled before the astronauts launch on their mission.

NASA seems to think it is a viable plan which is why they selected SpaceX to execute that part of the mission.

[fluoridation]

Wikipedia:

> After a multi-phase design effort, on April 16, 2021, NASA selected SpaceX to develop Starship HLS and deliver it to near-rectilinear halo orbit (NRHO) prior to arrival of the crew for use on the Artemis III mission. The delivery requires that Starship HLS be refueled in Earth orbit before boosting to the NRHO, and this refueling requires a pre-positioned propellant depot in Earth orbit that is filled by multiple (at least 14) tanker flights.

I stand by what I said: not happening. I'll believe it when I see it.

Can you imagine if to make a sightseeing trip to another city you had to stop in the middle of the highway and then make 14 round-trips with a second car to fill your first car back up? I can't imagine why someone would approve this plan, other than corruption.

[DarmokJalad1701]

> Can you imagine if to make a sightseeing trip to another city you had to stop in the middle of the highway and then make 14 round-trips with a second car to fill your first car back up?

If the alternative was throwing away and building/buying a new car for every trip? Absolutely.

They said the same about landing a first stage booster - impossible and pointless to attempt. And it just happened for the 400th time yesterday.

[dmbche]

False dichotomy - the mission profile dictates the refuelling station and all that, but it never was the only option. Somehow we've decided we needed to be able to do lots of trips to the moon for Artemis, but it's not clear to me that it's such a precious golden oportunity and warrants this spending/impact on the environnenent.

We didn't get to the moon with a refuelling station did we? How come we need one now? We're really seeing 15 starship launches per moon trip as reasonable, rather than just building a single trip program?

The mission itself is nonsensical. The problems are stemming from the SLS, I'll find a link to a relevant source.

[DarmokJalad1701]

> We didn't get to the moon with a refuelling station did we?

No. We did it by throwing away ~98% of the vehicle on the way there.

> How come we need one now?

Because building a new gargantuan tower and tossing that majority of it into the ocean/deep space every time we need to go the moon is not sustainable.

> We're really seeing 15 starship launches per moon trip as reasonable, rather than just building a single trip program

Yes. Because again. The alternative (dictated by physics) is that we expend the whole thing.

[dmbche]

And why do we need to do all this? This is the thrust of my point.

Making trips to the moon sustainable is pointless and nonsensical.

Edit0: good read https://news.ycombinator.com/item?id=40410404

[fluoridation]

>The alternative (dictated by physics) is that we expend the whole thing.

We can also, you know, not. We could put that money to something here on Earth instead of burning it up.

[DarmokJalad1701]

The money is not "burned up" - it is spent right here on Earth. It's paid to extremely skilled engineers, technicians and scientists.

The technology developed for doing such a difficult task will inevitably benefit all of humanity. It did so for Apollo. It will again in the future.

https://launiusr.wordpress.com/2012/02/08/why-explore-space-...

[stetrain]

The Apollo missions landed two crew members in a tin can with extreme limits on what weight they could bring with them in either direction.

A single trip launch will always be constrained like this due to the tyranny of the rocket equation.

A modular mission system with multiple launches is the best way to expand capabilities and enable things like landing larger payloads for more advanced or long-term missions.

[slipperydippery]

IIRC, the expected return payload for this is lighter than Apollo. In no small part because they're dropping all their return fuel and their entire return vehicle into the Moon's gravity well, rather than leaving it in orbit. Subjecting themselves to extra abuse from the good ol' rocket equation.

One of many wacked-out things about the plan.

[stetrain]

The vehicle that returns to Earth is Orion which stays in NRHO and does not bring its fuel to the lunar surface.

Return payload constraints are probably from using Orion as the return vehicle. Mass to the surface is much higher than Apollo since that is launched separate from the crew.

[fluoridation]

There's never going to be long-term crewed missions to the Moon. It has no scientific value. Even the little exploration we did in the '60s and '70s were a dubious proposition. There's not that much we could do by sending people that we couldn't do by sending robots.

[stetrain]

If you think there's no value to returning to the moon, building a base, etc. then fine. But you keep moving the goalposts of what you are taking issue with here.

[fluoridation]

And yet the boosters are not being reused. They're just making brand new engines for every launch. If we're generous they're being dismantled and recycled.

[stetrain]

They were talking about Falcon 9, which is absolutely being reused.

[fluoridation]

Alright, if we're talking about Falcon 9, I don't know what the cost savings are for a reusable rocket, or if there are any. If someone has that data, feel free to provide it.

[Powdering7082]

> As of 2024, SpaceX's internal costs for a Falcon 9 launch are estimated between $15 million[186] and $28 million,[185] factoring in workforce expenses, refurbishment, assembly, operations, and facility depreciation.[187] These efficiencies are primarily due to the reuse of first-stage boosters and payload fairings.[188] The second stage, which is not reused, is believed to be the largest expense per launch, with the company's COO stating that each costs $12 million to produce.[189]

From wikipedia: https://en.wikipedia.org/wiki/Falcon_9#Pricing

[0xffff2]

There are a lot of variables, but very roughly, the Falcon 9 has cut launch costs in half compared to its competitors.

[stetrain]

How did the fuel you put in your car get there? Your car didn't come with all of the fuel for the trip, nor did it spawn at the gas pump.

It was pumped, shipped, refined, and trucked to that point using a complex supply chain, enabling your final trip to happen with one fuel transfer.

[slipperydippery]

The mission is wildly more complicated than the Apollo missions. There's a whole oddball-orbit space station that has to be placed as a way-station, for one thing, and none of that's happened yet (remember how long it took to build the ISS?). Also, landing all your return fuel instead of leaving it in orbit, so a way heavier lander (with a smaller return payload than Apollo!), which is a pain in the ass. Multiple space ships launched by different rocket systems involved. The SLS still has to be finished for it to go forward. Orbital refueling of large fuel tanks is a hard problem that remains unsolved, and this goes nowhere without fixing that. The contracts for the return vehicles are disturbingly light on parts about making sure they can reliably work, including surviving re-entry.

I'm with you. Not happening. We're more likely to come up with a totally different, simpler plan, and do that instead, before this happens.

[stetrain]

> landing all of your return fuel

The fuel that is landed is used to get back from the lunar surface to lunar orbit, not to return to Earth. That fuel stays with Orion in NRHO.

[redox99]

You can easily mathematically prove that orbital refueling increases mission efficiency. This is a simple fact, it's not about Starship or whatever. Your analogy does not hold.

[stetrain]

> I stand by what I said: not happening. I'll believe it when I see it.

And it's totally valid for you to have that opinion. But it's your opinion, not "the consensus."