RCgothic

Cool, if all SpaceX wanted to do is send a flag and footprints mission to the moon or *maybe* Mars. And that might be a sensible way forward (for the getting Orion to the moon portion of Artemis before Starship gets rated for lunar returns) if SLS gets cancelled. But that is *not* what SpaceX wants to do. SpaceX wants a permanent base on the moon. They want a city on Mars. They want the ability to brake hundreds of tonnes of mass into orbit of the outer planets. And they want all that to be affordable on their own budget. Starship Superheavy expendable can accomplish some useful missions soon in the short term for a reasonable price. But frankly SpaceX would find that to be a distraction from what they actually want to do. If, as a nation, the US has different priorities, then I'm sure SpaceX wouldn't say no to a big cheque. But humanity would advance faster by investing in the long term goals SpaceX are pursuing rather than distracting them with short term dead-end avenues like flag and footprints (again).

SLS was also really good at shaking sensitive scientific payloads to pieces with those enormous SRBs. Nearly every bit of Artemis except the Landers and the EVA suits could be ditched and nothing of value would be lost. Getting rid of Gateway, Orion and SLS would save a lot of money for more regular flights and actual mission hardware.

The fabrication tolerances won't even hold 0.5cm over the whole booster. Thermal expansion/contraction alone would be much larger than that.

I would personally find 0.5m much more credible.

They have a second launch tower nearly ready. Not a big setback if they break the first. Much useful data to learn.

And even so there's no way impact explosion damage outweighs launch explosion damage. The quantities of propellant involved are just so vastly different.

Also the shipping channel is not exactly free from contaminants either. Of course SpaceX shouldn't be releasing contaminants into the environment. But I struggle to see how the deluge system puts anything into the ecosystem other than would be washed in by the regular storms.

Hypothetically it could come back safe 99 times out of 100 and still not meet human spaceflight safety criterion. Just because it came back safe this time doesn't mean astronauts should have been aboard. Clearly there was division over whether it was "good enough" or not, and we're not particularly well placed on the outside to second guess.

If they could even match Apollo cadence of 2-4/year this wouldn't be a problem. Kick the crew off the next flight to test and delay by 3-6 months. No big deal. Considering the space shuttle SLS is derived from managed significantly better than that in stretches I am genuinely baffled how they've so failed to match what came before.

This

Again, sure, if all we wanted to do was repeat Apollo. But we don't.

Whilst you wouldn't want to stay in the Van Allen belts, this isn't anything humans haven't done before. It'd take just under two months of exposure to the worst bits to accumulate a fatal dose with shielding of 3mm aluminium (25sv/year). Dragons are considerably better shielded than this, the trajectory will avoid the worst areas, and they aren't going to be staying there for months. A few orbits only. Apollo and Gemini both transited the belts with no ill effects to astronauts. Apollo doses were dominated by solar particles outside earth's magnetic field. I think it's awesome people are going beyond LEO for the first time since Apollo.

An RFA rocket just exploded at the UK's Shetland launch site: https://www.bbc.co.uk/news/articles/cy54wqzz0kvo.amp

Hardly anyone else even has a reusable S1. Only electron, to nowhere near the extent of F9 thus far. Reusable vs reusable battle is a long way off IMO. It's cool that Stoke, RL and BO are working on potentially competing approaches. Maybe Stoke's approach might be more easily realisable than starship. But for certain payloads (e.g. propellant) if each approach is fully realised that won't be anywhere close to as rapidly relaunchable as a "land on the launch tower". Additionally, having an enormous mass margin will certainly not hurt. If Starship achieves full and rapid reusability, but it only manages 25t payload to orbit and something like 300 tonnes are required for rapid reuse, that still undercuts Falcon, current market leader in cost efficiency per payload, by a factor of at least 5. If Stoke needs 50t dry mass to LEO for rapid reusability but total mass to orbit ends up being 40t, they'll be stuck. Also the "but it'll be oversized!" case is somewhat rebutted by pointing at the transporter missions that are currently eating smallsat launchers' lunch. If there's a payload capacity of 200t and a customer only needs to send up 2t, it'll be sent up with 50-100 other payloads and the "Cesna" won't compete against the "A320" outside of extremely niche applications.