"JF Mezei" wrote in message ...

On 2020-01-04 10:40, Jeff Findley wrote:

No, because that propellant is needed in case of a launch abort.

I was asking on whether propellant used for abort = propelland needed
for propulsive landing. Aka: had SpaceX been allowed propulsive landing,
would the fuel tanks for the super dracos have been bigger?

No, you're missing the point. The propellant was for one OR the other. You
want to ensure you've got enough fuel to accelerate quickly and far enough
in an abort and you want reserve for landing. So no. I don't believe there
was any difference.



With regards to landing gear: I have to wonder if that might not have
been the show stopper for NASA. Mechannically deployed landing legs seem
like a accident begging to happen if one fails to deploy/lock.


There's this concept called redundancy. And also accepting a harder, but
still survivable landing if one doesn't.

BTW, did the shuttle crew have cranks to manually lower the landing
gears like on planes at some point in time? Or is the time between
landing gear deployment and touching ground so short that it was
pointless to add manual gear deploy cranks?

The landing gear on the shuttle was deployed very late on approach. There
was no time to hand crank anything. Not even really enough time for a short
prayer if they fail to deploy.

NASA relied on explosive bolts to force the gear to deploy and gravity to
lock it in position. It was nearly foolproof.




a propulsive landing. In the event of a launch abort, Dragon 2 would
have used parachutes to splash down in the ocean.

Can Starliner launch over land if after an abort, the combination of
parachutes and inflatable mattress lets it land anywhere?


No, because you still need to launch the Atlas V over water for aborts.



insertion propellant. And in the case of a complete failure of
Starliner to perform that orbital insertion burn, it will simply reenter
as Atlas V puts it into an orbit whose low point is within the earth's
atmosphere.

So in the context of the recent Starliner test launch, how long after it
detached from Atlas and failed to activate orbit insertion engines,
would Starliner have re-entered? a few orbits or at the next perigee?

I believe at the next perigee.


Just curious how close to re-entry the ship was at the time ground
control re-established contact with it and started to "fix" it. I take
it a "confused" ship left to its own devices would have re-entered with
its service module still attached and not have realised it was
re-entering and not deployed parachutes?


No idea on this one.

(since its software seems so based on a timer).

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