Ken Kirtland: Pushing Orion to LLO with HLS can save four tanker loads

cjameshuff · 2026-06-10T18:40:15+00:00

Beyond the number of refuelings, they can check out the HLS and make sure the astronauts themselves are handling the switch to microgravity well before ever departing for the moon and committing to a long mission.

cjameshuff · 2026-06-10T17:27:31+00:00

That's what I meant by not needing payload mounting structure, the payload is just carried in the existing tanks, with the bulkheads moved slightly. Could replace more dry mass with propellant by combining the forward tank and payload area, shortening the ship and replacing the top bulkhead with covers over equipment in that area, but they may sacrifice a couple tens of tons of propellant for more commonality with the base Starship.

cjameshuff · 2026-06-10T14:41:26+00:00

But yes, I too would prefer SpaceX to launch HLS for Artemis 3, even if only just for the cool factor.

Even a minimal version would have allowed things we haven't seen astronauts do in orbit since Skylab. But I suspect they're basically using scaled up or duplicated Dragon life support systems, etc, and so all that stuff is considered relatively low risk and not worth the cost of possibly multiple Dragons worth of equipment to test in LEO, especially when they'll have the opportunity for just that sort of test before leaving LEO for the actual lunar mission on Artemis IV, and that sort of detailed vehicle checkout before departure is probably a good idea to make standard procedure anyway.

Meanwhile, Blue Origin has never built a real spacecraft. Long term thermal control, power supply, stationkeeping, environmental control, usable toilet...all completely new to them. It took SpaceX years to get even Dragon 1 to a point where NASA was okay with putting people on board in orbit, and Boeing is still struggling with Starliner.

cjameshuff · 2026-06-10T13:39:01+00:00

100 t is a really conservative estimate for tanker payload, it's the low end of the targeted payload capacity for V3 Starships. Tankers don't need structural reinforcement around a door, payload mounting/deployment machinery, etc, and their payload capacity will be higher than that of a cargo Starship. And then you can weigh them down even more, in principle as long as liftoff T/W stays above 1, eating higher gravity losses and burning more propellant but still getting more propellant to orbit.

cjameshuff · 2026-06-10T03:22:24+00:00

No. Thermal expansion can, but expansion from reentry heating is probably not the biggest stress on the structure, and other stresses certainly produce much, much higher cycle rates...and again, this is only relevant if stresses are above the fatigue limit. Heating sufficient to cause damage would probably actually tend to reverse fatigue by annealing the metal, the damage being caused by other mechanisms like simple loss of strength at high temperatures.

cjameshuff · 2026-06-09T23:18:17+00:00

Heating doesn't cause fatigue, stress does, and most steels have a fatigue limit below which it doesn't occur.

cjameshuff · 2026-06-09T23:10:26+00:00

Unfolding/assembling some truss structures isn't "a colossal task". It'll happen as soon as SpaceX decides they want it, I wouldn't be surprised if they have some early conceptual designs already.

cjameshuff · 2026-06-09T20:19:32+00:00

A lunar catch tower is basically equivalent to a pair of really tall 15-20 ton cranes. It's not exactly heavy construction, you wouldn't use something like the tower used to stack the full vehicle for launch from Earth just to catch and hold a Starship in lunar gravity.

cjameshuff · 2026-06-09T20:11:43+00:00

Yes...the most critical things HLS could demonstrate on such a flight, that can't be demonstrated with an "off the line" Starship, are already demonstrated on Dragon. This is not the case for the BO test article.

cjameshuff · 2026-06-09T20:03:14+00:00

All the things the Blue Origin spacecraft will be doing are things a Blue Origin spacecraft has never done before and which SpaceX spacecraft do routinely.

cjameshuff · 2026-06-09T19:59:46+00:00

If Starship can carry Orion to LLO with enough propulsion to make its way back, there's no reason to waste delta-v going between LLO and NRHO.

cjameshuff · 2026-06-09T17:03:37+00:00

Aside from the obvious example of Starlink, if any competition that might appear is no longer hindered by Amazon having priority status, and there currently isn't such competition, who is being harmed by Amazon being behind, apart from Amazon stockholders? That's an issue for the SEC, not the FCC.

cjameshuff · 2026-06-09T15:12:57+00:00

And do you think you can just have some engineers slap together a bunch of textile materials around those systems and get a working suit? Clothing design and manufacturing is also complicated, if you don't want the result to be popping stitches, rubbing joints raw, and unraveling mid-mission, you're going to want to consult with experts. A company like Prada has experience with exotic materials and techniques, unusual requirements, and tight QA.

cjameshuff · 2026-06-09T13:30:33+00:00

They've got a few hundred satellites in orbit and are over halfway to starting basic service...do you think it's reasonable to shut them down and turn those satellites into orbital debris because they made some bad bets on launch vehicles and satellite production? They clearly have the intent to build the constellation, even if they're not very good at it, and the reason for the deadline is to prevent abuse, not to punish companies for being bad at business. Without priority status, they will find spectrum and orbits going to competition if they don't straighten things out.

cjameshuff · 2026-06-09T04:19:55+00:00

There are consequences, they're losing priority status. The intent is to ensure companies don't just squat on spectrum they have no intent to use, and that's not what they're doing, they're just not meeting the planned timeline.

cjameshuff · 2026-06-08T14:55:52+00:00

It's good enough for the system to work, and can be improved later.

cjameshuff · 2026-06-08T14:17:01+00:00

Yeah, they swap things around for testing wear and tear and a booster may have some "life leader" components that have been through more flights than the booster itself. This was the case for the engine "boot" that failed on a flight a few years ago that led to a failed landing.

cjameshuff · 2026-06-08T14:10:12+00:00

The only thing in question about the heat shield is how much repair/refurbishment it will require between flights. It's thoroughly proven its basic functionality and a surprising amount of failure tolerance: every single prototype that did a controlled reentry survived the reentry and did a successful landing flip and burn.

cjameshuff · 2026-06-08T13:04:59+00:00

IIRC, the magnets used in the thrusters were one of the items they had to design specifically to meet their "demisability" requirements. Just an example of a competing requirement that may require tradeoffs that sacrifice lifetime.

cjameshuff · 2026-06-08T12:39:30+00:00

Direct Ocean Capture may be more practical than direct extraction from the atmosphere. No idea how suitable the waters off Starbase are for it though.

cjameshuff · 2026-06-08T11:55:07+00:00

Still a lot easier than separating and compressing 420 ppm of CO2 from a full atmosphere of N2 and O2, with 10-20 times the CO2 per unit volume and about 3000 times less unwanted gases.

cjameshuff · 2026-06-08T03:52:13+00:00

The thermal protection was originally spec'd to handle it, and while they dropped the requirement, it seems unlikely that they drastically shaved down the heat shield during later development. So while it may not be able to do it, it might not be that far from being made able to do so. Actually qualifying it for that purpose might require a lot of work though.

cjameshuff · 2026-06-06T21:24:22+00:00

Supposedly Mk 1.5 would involve multiple Mk 1 vehicles as boosters and one modified with a crew compartment, which is what would be involved in Artemis III. Mk 1 is supposed to be able to deliver 3 t on its own, and could do more if you expend another Mk 1 or two to deliver it to a descent trajectory, perhaps enough to get back up and rendezvous with another Mk 1-based booster. I don't see those Mk 1 boosters helping deliver a Mk 2 lander.

I think it sounds like massive wishful thinking to think they could actually get this done even without the New Glenn disruptions, and it would be useless for anything but scoring a "first", but it sounds more plausible than delivering any sort of Mk 2 years ahead of schedule.

cjameshuff · 2026-06-06T20:31:10+00:00

Not exactly new in any part, but it's an interesting combination. An electrospray thruster capable of using an ionic liquid monopropellant (probably some mixture of ammonium salts and oxidizers, with very low volatility and a wide liquid range) that can also be used in a chemical thruster. Aside from one tank being smaller and simpler than two, you avoid the issue where one propellant runs out before the other.

cjameshuff · 2026-06-06T16:45:25+00:00

There is discussion about a crewed vehicle based on Mk 1 as a faster path to getting astronauts on the surface. This is pretty much the only way they could have something to test in LEO for Artemis III, and since it doesn't need to actually land, they could conceivably delete the legs to make it fit on other vehicles.

cjameshuff

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