[Campion]

If they’re launching from orbit, they’re starting at Mach 25. To enter the atmosphere, they have to slow down, not speed up. (If you’re in orbit and you speed up, you go to a higher orbit, or you achieve escape velocity and leave earth.)

[doorgunner69]

From my shallow understanding of orbital mechanics, the slow down speed up is assuming a velocity vector in the direction of travel.

What happens if the thrust is directly down toward earth? I know de-orbiting space capsules have to be careful not to come in too steep and burn up, but with a rod, just make it steep enough to retain velocity?

[CodeToad]

“If they’re launching from orbit, they’re starting at Mach 25. To enter the atmosphere, they have to slow down, not speed up. (If you’re in orbit and you speed up, you go to a higher orbit, or you achieve escape velocity and leave earth.)”

Umm....no.

You only escape Earth’s gravity if you are headed away from Earth. If they are accelerating towards Earth how do they leave Earth??