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 into the ocean, after a complete parachute failure.

Spy satellite film capsules (remember film?) were 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 a guesstimated unladen structural load limit of 1.7 gees, the stall speed might be 90 m/s. Inverted at this velocity, the 90° vertical turn radius (from horizontal flight to a vertical dive) would be less than 500 meters.

A StratoCatcher aircraft would be much smaller than Stratolaunch, designed for 10,000 km flights. It would be designed to capture a 20 tonne spacecraft (perhaps a Mars crew return vehicle, 3.6 times the mass of the Apollo command module) in a 170 m/s vertical dive at perhaps 9000 meter altitude. Before the drogues deployed, the Apollo command module descended at that speed 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. A backup aircraft would drop motorized rafts, survival gear, and recovery crew for support, until a seaplane could be sent to collect the crew and return them to a major airport.

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).


150 m/s is the free-fall velocity from a 2.3 kilometer drop. I can imagine developing this capability by playing "catch" between two modified 300 knot jet aircraft a few hundred miles off the Pacific coast, hundreds of tests per month. The first application might be scavenging; characterizing satellites with decaying orbits and catching them on the way down. DoD might pay big bucks for a peek at satellites lost by "the competition", and to keep their own satellites from (literally) falling into the competition's hands. Catching nuclear powered satellites might require special handling, but it could avoid multimillion dollar ground cleanups.


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 supplied by a launch loop, the designated landing area could be serviced by dozens of StratoCatchers. Each aircraft could recover many crew return capsules per day.

Servicing emergency 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 good solution --- yet.

Almost every space wannabee obsesses about launch, but launch can be more profitable if missions are more valuable. Missions are more valuable if their success probability improves, and less hardware (primary and backup) is needed for successful completion. This is a neglected opportunity that can be dominated by early entrants; why risk multimillion dollar missions on newbies without track records?

Useful technique will be developed with experience, not with patent applications; while patents may enrich the early entrants, knowing what to patent will come from experience, not theorizing, and demonstrating a technique (recording and witnessing and timestamping the experiments) is the best way to establish prior art. Just Do It, so your lawyers can win.

StratoCatcher (last edited 2018-09-16 09:06:07 by KeithLofstrom)