I looked at this, and their "revolutionary" APU appears to be a piston engine. Liquid cooling, inverted oil system... this was old hat before WWII.
Helium-free pressurizing apparently means heating the cryogens to maintain pressure as liquid is taken off.
There were boosters which used the turbopump exhaust for attitude (particularly roll) control but I'm not enough of a fanatic to recall which ones. If the APU is running, there's your stream of exhaust for reaction control.
All of this could have been done 20, 30, 40 years ago. What went wrong?
I looked at this, and their "revolutionary" APU appears to be a piston engine. Liquid cooling, inverted oil system... this was old hat before WWII.
ReplyDeleteHelium-free pressurizing apparently means heating the cryogens to maintain pressure as liquid is taken off.
There were boosters which used the turbopump exhaust for attitude (particularly roll) control but I'm not enough of a fanatic to recall which ones. If the APU is running, there's your stream of exhaust for reaction control.
All of this could have been done 20, 30, 40 years ago. What went wrong?