"djarvinen" escribió en el mensaje
oups.com...
On Aug 21, 10:07 am, "hg" wrote:
"nmp" wrote in
...
djarvinen wrote:

I was watching the live pics of STS-118 landing today and noticed that
the landing gear doesn't come down until what appears to be just
seconds
(10-15?) before landing.

So what's the procedure if the gear doesn't come down? I'm pretty
sure
a go-around isn't an option.

I'm no technologist or expert but even I can figure that one out. The
procedure is: put her down with her belly on the ground, and let's see
what happens. Like you said, there is no alternative either way.

Could be a problem as the orbiter has a flat underside. Sounds like a
recipe for a flip-over tail-over-nose.

I was kind of wondering if they had some sort of emergency gear down
procedure; perhaps an explosive type mechanism that would force them
down. But it seems like the time frame is so small, that that kind of
solution might be worse than than no gear down at all.

Certainly they must have some plan, even if it is only 'hang on!'.


http://www.globalsecurity.org/space/.../sts-gear.html
For deployment of the landing gear, the uplock hook for each gear is
activated by the flight crew initiating a gear-down command. The uplock hook
is hydraulically unlocked by hydraulic system 1 pressure applied to release
it from the roller on the strut to allow the gear, assisted by springs and
hydraulic actuators, to rotate down and aft. Mechanical linkage released by
each gear actuates the respective doors to the open position. The landing
gear reach the full-down and extended position within 10 seconds and are
locked in the down position by spring-loaded downlock bungees. If hydraulic
system 1 pressure is not available to release the uplock hook, a pyrotechnic
initiator at each landing gear uplock hook automatically releases the uplock
hook on each gear one second after the flight crew has commanded gear down.

--

Cheers