sevenperforce

Total and complete non-starter. You might as well try to suggest trying to manufacture JP-1 while flying over the Pacific ocean in a 747.

Per NASA, the first ICPS burn after staging off the SLS core does an insertion to a 185km x 2900km orbit. The second ICPS burn raises the stack to a 378km x 109,400km orbit. Then Orion provides the final burn at perigee for TLI. A circular LEO at 185 km is 7.80 km/s, and so the initial ICPS orbital insertion is about 640 m/s more than that (velocity at perigee = 8.44 km/s). The second ICPS burn would need to add about 2.21 km/s (velocity at perigee = 10.56 m/s). That puts them in a 42-hour orbit which NASA is saying for "spacecraft checkout" and practice. Then Orion burns about 3 tonnes of its propellant to complete the TLI. Should be a 5-6 minute burn. So yeah, that's four extra passes through the inner Van Allen Belt and two extra passes through the outer Van Allen Belt. All to get a free-return that Falcon Heavy and Crew Dragon could do with ease. And then with Artemis III they won't even be able to achieve the safety of a free-return.

Holy crap THE PRECISION What an amazingly precise orbital insertion to still be that close after that many orbits. There are plenty of contingency situations where you might want two capsules to dock.

Artemis I will enter a distant retrograde orbit. Orion will do a very close flyby -- 100 km -- in order to do a mostly gravitational capture into the distant retrograde orbit. So there will be the nice close-up views that @YNM wants...except for the fact, of course, that there is no one on board. After six days in the distant orbit, it will lower its perilune and do another Oberth burn to get to Earth entry interface. Artemis II has to do a multi-translunar injection with two burns (unlike Artemis I) because a free-return is more dV-costly. Artemis III will not be able to do a free-return since it will be setting up to enter NRHO. But sure, let's keep SLS because it is soooooooooooooooo safe.

As others have pointed out, even a Tesla can technically be coal powered. I believe that Tom Sawyer Abroad features a nuclear-powered balloon but it is properly a parody of Verne's work. EDIT: Ah, yes, here's the quote. It was a noble big balloon, and had wings and fans and all sorts of things, and wasn’t like any balloon you see in pictures. It was away out toward the edge of town, in a vacant lot, corner of Twelfth street; and there was a big crowd around it, making fun of it, and making fun of the man. The professor had been quiet all this time, as if he was asleep; but he broke loose now, and he was mighty bitter. He says something like this: "Idiots! They said it wouldn't go; and they wanted to examine it, and spy around and get the secret of it out of me. But I beat them. Nobody knows the secret but me. Nobody knows what makes it move but me; and it’s a new power—a new power, and a thousand times the strongest in the earth! Steam’s foolishness to it! They said I couldn’t go to Europe. To Europe! Why, there’s power aboard to last five years, and feed for three months. They are fools! What do they know about it?" I believe at some other point in the book he says the balloon's power is heat, and it comes from the same source as the sun. Not that Samuel Clemons knew what nuclear fusion was, mind you.

Not really. Medusa and Orion are about equally achievable.

If you're going interstellar then just bite the bullet and light up a NSWR.

I don't anticipate any quadcopters on the moon. The challenge for making a bigger Ingenuity is going to be power. Ingenuity uses its solar cells to recharge its battery, but it depends on its battery for its hops. It can do about 90 seconds but you'd need more than 90 seconds of flight time on a larger version. Adding more batteries is going to add more weight which is a vicious cycle for something operating so close to the limit of...well, everything. The air really isn't dense enough to do anything with a Coanda effect.

They are decidedly not too small to take into account. They have a dramatic effect.

I don't mean using the Lunar Starship alone; I mean using the Lunar Starship as the tug. It merely needs to have one post-TLI retank. Exactly the same mission architecture as above, except that Crew Dragon remains attached to the Lunar Starship after step 6.

That's fine if you want the CCV to be the primary vehicle for getting to and from the moon, but neither Starliner nor Crew Dragon are really designed for that. And it requires the creation of a third vehicle. Easier to just use Lunar Starship for everything.

Well, that concept would do retanking in GTO, not GEO, which means you have phasing concerns and the same Van Allen belt issue. There are a lot of mission architectures which would be quite efficient but wouldn't be acceptable to NASA. Nor should they be. You need an intact abort mode at all times -- or, if that's not possible, you need an intact abort mode for as much of the time as possible. And once you have crew on a vehicle, you want as few "mission-critical" steps as possible. So NASA would not be okay with a mission architecture that requires a retanking event before the crew can come home. You wouldn't want to end up with a situation where the crew are stuck for an extra week in a prop-depleted Lunar Starship, floating in GTO, because something went wrong with GSE and the retanking mission got delayed. That doesn't mean you can't have a retanking event with crew on board. It just means that you have to do it in such a way that an intact abort mode is preserved if the retanking goes wrong. For example, if you want to do Artemis with Crew Dragon and Lunar Starship, you could do this: Launch LS to LEO Retank LS Launch a Tanker Starship (TS) to LEO Retank TS Launch Crew Dragon to LEO on Falcon 9 Crew Dragon docks to LS, crew transfers TS and LS both burn for TLI with a free-return Immediately after the TLI burn, TS and LS rendezvous TS retanks LS TS makes its loop around the moon and then re-enters and lands at Boca Chica LS performs lunar mission and propulsive return to LEO Crew Dragon docks to LS, crew transfers Crew Dragon deorbits with crew Return to step 2 This way if there is a problem somewhere in steps 7-9, LS still has more than enough propellant to cancel the landing and just return to LEO propulsively. The "retank-after-TLI" option above would work perfectly well with "take-the-CCV-with-you" architecture.

I want to see Iron Man suits for EVA, damn it. Rigid mechanical counterpressure to provide constant-volume joints for a flexible pressure suit. Oh, wow! I didn't realize he gave me the shoutout. Lemme go thank him. An intermediate option not noted in the video: you can man-rate Falcon Heavy but not otherwise update Dragon 2, which allows SpaceX to put an ordinary Dragon 2 into GTO. Dragon 2 already has enough propellant onboard to get back to Earth from GTO. So then you stage everything from GTO from start to finish. The only issue is phasing -- you have a smaller window of possible return dates since you have to match Dragon 2's argument of periapsis. Obviously doing a dedicated tug as you have proposed opens everything up even more.

I'm not inclined to read too much into the graphic.

Where?

@taterOh these are fun. Dynetics: "Mass estimate physically impossible and at negative margin" Blue Origin: "Unsubstantiated claims for commercial approach" Dynetics: "Lack of awareness of schedule risk" Dynetics: "Lack of detail and technological justification for refueling process" Blue Origin: "Uncertainty over propulsion system component suppliers"

I wonder how many refueling missions this will take and whether they will have reserves to attempt an aerocapture return to LEO.

I agree with all of the above. My point is that they now have a similar OML to the regular starship, which would suggest commonality, but there is none. I will point out, however, that they still need to actuate in the first place. They can't launch deployed like that -- the aero loads would be impossible.

Looks like four banks of six engines each for a total of 24.

Close view on the legs. This just looks like a really ridiculously sloppy render to me. See how the feet clip through the fairing on one side but not the other?

We've got new legs! And they look remarkably similar in shape to the ones shown in the most recent #dearMoon renders. But...but there's no way SpaceX would put a seam in their heat shield! Would they? Could they? And even if they did, surely the heat shield wouldn't contact the ground directly! I'm convinced that they are just spitballing at this point. Those new legs don't have any actual actuation path.

Only mean if you make them in RO. It's mean by calling more attention to it, I think

Whatever "the aliens" used to get here would require some pretty extreme technology. Even if their tech was anything we could possibly create (such as the Orion), they would be likely be operating on timescales of thousands or millions of years. Such an alien "invasion" might not contain any members of the species/culture/whatever who built it but would be just a delivery pod for the "de-terraforming" equipment and lifeforms (assuming the "equipment" is some sort of self-replicating nanotech, the differences would be academic). Oh, I'm not talking about aliens getting here. I mean if aliens were using Orion drives to zip around in their own respective solar systems. Thermonuclear weapons are momentarily brighter than a star and produce distinct x-ray signatures, though of course total luminosity is not comparable to that of a star. But suppose there were aliens on some of the planets or moons in the Alpha Centauri system. Suppose further that they were spacefaring and had graduated to Orion Drive vehicles to use for moving stuff around their system. Would any of our telescopes be able to pick up the characteristic pop-pop-pop-pop-pop of an Orion Drive? Or would the energy output be just noise against the background of the star system?

The sheer hilarity of tiny Orion docking with that gloriously massive Starship

Would they potentially only choose one? UPDATE: They chose SpaceX alone. https://www.washingtonpost.com/technology/2021/04/16/nasa-lunar-lander-contract-spacex/