StratoCatcher

Launch is important. Returning intact is even more important. Sending a parachute to Mars and back is expensive; insuring that ithe parachute still works after years of outgasing, radiation, and heat cycling may be more difficult than the mass-cost of launching the parachute system.

Apollo deployed drogue chutes at 150 m/s and 7300 meters altitude. What if those parachutes, or the main parachutes, had failed?

The 275 kg Genesis sample return capsule crashed in 2004 with a terminal velocity of 86 m/s after a 11 km/s entry - about the same velocity as an Apollo crash would have been, after a complete parachute failure.

Spy satellite film capsules used to be snagged in midair by aircraft; that got the film to the analysts pronto. After an emergency in space, getting wounded astronauts to full-capability hospitals is also time critical. The US deployed large recovery fleets for NASA space capsule landings, because we had the fleets and it was great publicity for the Navy. Private space can't afford this, and we can't afford to launch expensive planetary sample return missions that fail.

In the thin (0.3 surface density) air at the 11 km launch altitude of the Stratolaunch aircraft, with presumed structural load limit of 1.7 gees, the stall speed might be 90 m/s. Inverted at this velocity, the vertical turn radius would be less than 500 meters.

A StratoCatcher aircraft would be much smaller than Stratolaunch, but with a much farther service range. It would be designed to capture a 20 tonne spacecraft (3.6 times the mass of the Apollo command module) in a 170 m/s vertical dive at perhaps 9000 meter altitude, the vertical ballistic velocity of the descending Apollo command module at that altitude. The StratoCatcher would then deploy (very sturdy) drag flaps and lift at 1 gee while decelerating, pulling back to level flight at perhaps 4000 m altitude.

If capture failed, the spacecraft would depend on its (backup) parachutes and water landing flotation. Subsequently on and motorized rafts, survival gear, and auxiliary surface crew dropped by the StratoCatcher.

However, "business as usual" would be the StratoCatcher slowing and reeling in the spacecraft, securing it for landing and transferring the spacecraft crew to the main aircraft. They would be flown to a crew receiving center at a major commercial airport.

A libreoffice spreadsheet with guesstimated Apollo capsule descent (no drogue or main parachutes).

Why?

The Earth is huge, and space centers and hospitals rare. Oceans cover 70% of the planet, and arranging to return to a specific landing site after a long journey is troublesome to arrange in the best of circumstances. In an emergency, a spacecraft might come down almost anywhere. A small fleet of StratoCatchers can be deployed around the globe, and participate in spacecraft reentries over a wide region, especially emergency re-entries, minimizing surface infrastructure and greatly reducing the need for recovery fleets.

For a construction orbit serviced by a launch loop, the designated landing area could be serviced by dozens of 1StratoCatchers. Each aircraft could recover many crew return capsules per day. Servicing crewed launch aborts, which might descend over a broad swath of the ocean or land almost anywhere west of the launch loop, is a big problem with no solution --- yet.

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