Advanced Re-Entry Vehicle

[Ironclad]

Why would re-entry craft 'bounce' off the atmosphere when the upper atmos is so thin in depth and thin in gasses?

[Coito ergo sum]

Rear entry in a vehicle can be tricky.

[Ironclad]

No it isn't. In broad daylight it is legally dangerous mind.

[mistermack]

When you decelerate from orbit, you automatically lose altitude unless you apply lifting thrust, which would require that the spacecraft lug around huge amounts of extra fuel, from lift-off to mission completion. You'd wind up hauling so much fuel per tonne of payload that the whole thing would turn out to be unfeasable.

You can design the vehicle so that some of the drag forces supply lift, instead of just retardation. So the retardation is less, and therefore takes longer.

Like the linked article said, the re-entry of the John Glenn capsule was done without lift, and it experienced 8 g , whereas the shuttle employs a "lifting re-entry", it takes longer, and experienced 0.5 to 1 g. It actually spends time flying on it's side, in a series of s figures, so that the "lift" is not upwards, but sideways. I don't fully understand it, but that's what it says.

[mistermack]

Why would re-entry craft 'bounce' off the atmosphere when the upper atmos is so thin in depth and thin in gasses?

It's the vast speed, like if you skim a stone on a pond. The stone would normally sink (like a stone), but the speed results in upwards thrust.

Cos the pond is virtually flat, the stone eventually slows and sinks, but if the pond was a ball of water in space, the stone could skim off into space.