On 19 Sep 2003 08:22:53 -0700
(Vincent Cate) wrote:

When a stuntman jumps off of a build, he lands on a large airbag. The
idea of having a reusable capsule land on a huge airbag seems interesting.
If the capsule has some lift (like Apollo) and a parafoil, it seems
we could get a capsule to do a pinpoint landing and even flare at the
end. This should be gentler on the people and avoid the salt water
corrosion problem of landing in water.

You would of course want 2 parafoils, 2 computers, 2 differential GPS units,
etc. The capsule would be reusable as long as it hit the airbag, and
have a crumple zone (like a car, Armadillo Aerospace, or Apollo seats)
in case it missed. It might not be reusable if it missed, but the people
should survive. People survive car crashes with less deceleration
protection than a form fitting couch.

As long as the crumple zone is made of things you needed anyway, it
should be lighter than landing rockets, landing gear, or a large parachute.

Does a crumple zone seem reasonable?
Is the pinpoint landing the only big problem with this?
Could it be done reliably?

I think it would be better if the airbag was attached to the spacecraft. Wasn't this the issue with John Glenn's heat shield? That instruments suggested that an airbag had dislodged the heatshield?

The airbag would only have to be a metre deep or so to significantly reduce the G load at impact. And they are light, and they have been known to work: Pathfinder.

How about using a contact probe to trigger the bag inflation? Perhaps the sequence could be:

1. Drop the heat shield
2. Deploy the contact probe
3. Fire the airbag when the probe detects the surface.
----
Michael Smith
Mail address and GPG key available from www.netapps.com.au

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