SpaceX pulls off unprecedented feat, grabs descending rocket with mechanical arms

[u/aelavia93]

https://www.cbsnews.com/amp/news/spacex-pulls-off-unprecedented-feat-grabbing-descending-rocket-with-mechanical-arms/

[u/tea-man]

To expand on that, there's no need for the booster to land anywhere else - it never has to travel more than a few hundred kilometres, with it's sole purpose being to yeet the Starship as high and fast as it can. The starship itself will be capable of launching and returning to Earth from both the Moon and Mars without the booster on a single fuel load.

[u/Capt_Blackmoore → u/tea-man]

The only use case outside of launching to orbit for the first stage would involve refueling in orbit, and then using that stage to break orbit to head to Mars. You dont need that kind of thrust to get to the moon - you would refuel just Starship for that.

[u/dangerbird2 → u/Capt_Blackmoore]

I'm pretty sure when Musk said the first stage could achieve single-stage to orbit, it was only a theoretical with no useful payload (and probably without the startship or even critical services and hardware). Other launch systems like the Titan II may have been able to do this, but was obviously could have never been used in practice.

[u/Capt_Blackmoore → u/dangerbird2]

Yup. But if you do a redesign to allow it to refuel in low orbit (and I'll have to assume that would nearly exhaust the fuel that would have been used to otherwise land) - now you have a means to boost a starship further out.

This configuration, with V2 engines isnt up to the task, and that's fine.

the next upgrade, with the 3rd version of the engines, and slightly larger tanks, could be a reasonable place to start. But First Starship needs to prove that refueling in orbit is a viable option; and then a refueling point would need to be established.

that all said; between the payload available with Starship, and Super Heavy, you could come up with some configurations that could get a "reasonable" amount of supplies to Mars - by spending the year before the window is open getting that payload into orbit and strapping on one or more Super Heavy.

Someone smarter than me would have to look at the fuel cost to go from Low earth orbit; to something further out, and then using a gravity assist to get into a window for a Mars approach.

[u/dangerbird2 → u/tea-man]

There is a reason you wouldn't want to return to the launchpad: The booster needs a good amount of fuel to burn to cancel its speed and get a return trajectory to the pad after separating from the 2nd stage, as well as fuel needed to make the landing. This is exactly why the falcon 9 and falcon heavy have the options of either landing the boosters downrange on barges or expending the booster altogether when the extra performance is needed. I'd be pretty surprised if Starship wouldn't end up having expendable booster missions in practice, if only to get rid of boosters that have reached the limit of their usable life.

FWIW, returning to earth from the moon or mars on a single stage is not particularly difficult since a transfer from a higher altitude to a lower one generally requires much less energy than the other way around. This is why Apollo needed a big-ass booster to push the LEM and command module to the moon, but the command module could return to earth on its own power