On 2020-07-05 6:04 PM, JF Mezei wrote:
On 2020-07-04 20:14, Sylvia Else wrote:
Will it actually be able to rise to 200,000 feet using buoyancy?

More questionable, is whether it is possible to accelerate such a body
to orbital speed using low thrust. As its speed rises, so will its
altitude, but also so will the drag from the residual atmosphere. It is
far from clear that it can achieve orbit that way.

Isn't it more likely that the ship would be dropped from the balloon and
ignite rockets to quickly accelerate to orbital speed before it falls
down to the ground?

And how do you get back down without a TPS? Or are you only interested
in a one-way trip?

You should read over the documentation a little more carefully.
It seems clear the "orbiter" part of the design is also a balloon in a
wedge shape. That is to allow for *gradual* descent back into the
atmosphere without having to worry about lift and control vs heating
during descent.

It's interesting tho, I didn't see how the engine configuration as drawn
shows how that's possible unless the engines have reversible thrust. The
balloon wedge geometry would be wrong if you inverted the craft for decent.

[snip]

Would be interesting for aircraft design though with regards to Max-Q.

I agree with the latter. This is the slow path to/from orbit.

Dave