2 ms·

My understanding is second stage is harder, first because of the rocket equation. Every Kg on the second stage is much more costly than an additional Kg on the

My understanding is second stage is harder, first because of the rocket equation. Every Kg on the second stage is much more costly than an additional Kg on the first stage. Second, the second stage needs to go into orbit before it can return. That's much more speed and a harder reentry. Third, you have to deal with thrust. Falcon 9 has 9 engines, which means the landing burn can uses 1 engine for 1/9 of the thrust. This is still too much power and F9 currently needs to do a suicide burn. You can't do that with only one engine on a stage that is 1/10 lighter than the first one. Fourth, second stage has a vacuum engine with a nozzle not fit for atmospheric use. It's so thin and flexible it would probably crumble or disintegrate upon entry.

AstralStorm 10y ago
You could parachute it assuming it survives reentry, which is the first hard problem. The second problem is that chutes have to be replaced and are very tricky to install to work reliably. Plus they're another component. Second stage being lighter helps with parachuting it down. Also have to calculate if the extra weight of the chute makes it economical still.
- api 10y ago
  Hmm... well I doubt parachutes are any harder than landing a rocket on a barge, so I'm sure this could be done. Sounds like one possible path. The stage may sustain some damage on landing but it would allow at least some of its more costly parts (engines, electronics) to be re-used and the rest of the material to be recycled.