4 ms·
> Enjoy the view etc, and then the second stage relights to cancel your velocity to 0 That is not feasible. Your second stage would have to be roughly as large
by thebluehawk 8y ago
> Enjoy the view etc, and then the second stage relights to cancel your velocity to 0
That is not feasible. Your second stage would have to be roughly as large as an entire orbital rocket in order to slow itself down from orbital speeds to zero, which means your first stage would have to be massive in order to push the second stage into orbit.
The reason every vehicle that re-enters the atmosphere uses a heat shield is because it's way easier to carry a relatively light heat shield that sheds off the speed than to carry the massive amount of fuel to shed off the same speed.
See https://what-if.xkcd.com/58/ https://what-if.xkcd.com/58/
- SketchySeaBeast 8y agoIf instead of a circular orbit you just went for an arc with a really high apoapsis you could probably burn a little fuel to reduce the forward momentum to zero, and then proceed to slowly plummet back to earth... which then means you need a really big heat shield as that gravitational potential energy turns back into kinetic and you smack into the atmosphere at a ridiculous velocity. Scratch that, too much Kerbal.
- walrus01 8y agoa tall suborbital parabola that falls back into the atmosphere at an 85 degree angle is basically the same re-entry heat as if you were to do what you described, fly the parabola, and thrust retrograde at apoapsis to cancel out the downrange velocity, then fall into the atmosphere dead vertical. It's horizontal velocity (actual LEO velocity) that causes the heating effects a Soyuz or Dragon type capsule needs to survive with heat shield on re-entry.