Unmanned U.S. Air Force space plane lands after secret, two-year mission

Re:Unmanned U.S. Air Force space plane lands after secret, t... by nradov on Tuesday May 09, 2017 @12:40AM (#14297774)

Orbital velocity is no asset. In fact rather the opposite. You can't just start aerobraking. There isn't enough air in orbit for parachutes or wings to have any noticable effect. The only practical way to get out of orbit using current technology is to conduct a de-orbit burn with chemical rockets.

Of course that's all pointless because a ballistic missile launched from Earth could accomplish the same mission at a far lower cost with greater reliability and survivability.

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Re:Unmanned U.S. Air Force space plane lands after secret, t... by ethbro on Tuesday May 09, 2017 @12:59AM (#14297832)

You absolutely can just start aerobraking if you have maneuverability on the launch vehicle (because it's small, packed with fuel, and limited duration).

Regardless of what orbit you start from, you dip into the atmosphere, deploy your payload from there, voila.

Now anything you dropped has to deal with a furnace of superheated air, and the question of whether it's possible to have control in those conditions, but it's definitely going to de-orbit.

And the atmosphere is going to supply most of the energy, rather than direct retro burns from the delivery vehicle.

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