No escape tower on Dragon / Falcon 9

On Sep 29, 11:05*pm, Jochem Huhmann wrote:
writes:

"the company is considering replacing the escape tower with an
integrated escape system using propellant intended for deorbit,
“because you’re going to want to escape or deorbit, but not
both,” Musk noted."

Straight thinking, but a bit too straight... These are very different
scenarios: In one you want the capsule to move away from an exploding
booster as fast as possible, with very little need for an exact
trajectory, and in the other you want a rather gentle, but very precise
firing. Deorbiting by getting a hell of a kick in the butt with 20g is
not exactly what you want anyway.

So use an adequate number of smaller motors. For escape, fire them
all at once. For de-orbit, fire a few at a time, symmetrically-
positioned.

Since escape thrust should be reliably survivable, and de-orbit
acceleration can be at least as great as average ascent acceleration,
the total number of motors need not be large.

Align the motors through the centre of gravity, so that if one fails
to light the capsule is not made to spin and is sent not far off-
course.

--
(c) John Stockton, near London, UK. Posting with Google.
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