"How do you deploy an inflatable ballute from a craft entering an atmosphere at 20km/s? "
You deploy it outside the atomosphere. The clue is from *outside* the atmosphere. Inital atmospheric pressure is a millionth of ground level. Its *differential* pressure that keeps it solid.1KPa (c0.147psi) is enough to keep it rigid at this altitude. The vehicle is enteriing at a shallow (<10 deg max) angle to the horizontal.
How do you keep the ballute attached to the craft?
I'll presume your looking at the cords. Both Alumina and Zirconia based fibres are available (Melting point to 1800c/3300F) but its not clear if this is available in long form. Carbon fibre would need protection. FeCrAlY is in wire form and usable to 1400c. The ami is to keep the deceleration low and the lift high.
" How do you Stop the ballute deflating if it's hit by a micro-meterorite?"
Initial work on this in the 1960s has the high temperature mesh/fibres on the outside with the pressure membrane. Its an inside out tyre.
"Yet another business designed on the model of consuming R&D money for profit."
Ex NASA guys get their old buds to cough up some cash to pursue their pet project.
Sure sounds that way. But this idea has knocked round since the 1960s and it should be pushed further. SBIR is a good idea in theory but I wonder just how many of those SBIR start-ups actually blossom into self-financing companies with *real* incomes and products someone can buy. Otherwise its basically corporate welfare.
Mine is the one with the basic re-entry book written in the 1960s in the pocket.