Author Topic: Landing an MVac  (Read 10814 times)

Offline Kaputnik

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Re: Landing an MVac
« Reply #40 on: 03/17/2017 07:36 AM »
i just do not want to make another topic so this seems close enough.

what if reuse just most valuable part of the 2 stage - engine? it has compact size so no need to big heat shield. it has integrated heat tolerant tail stabilizer so no need to worry about center of mass problems. it is light weighted (400 kg?) so no need for big shute an the end.  and even small helicopter could catch it in the air.

My gut feeling is that it won't pass cost-benefit analysis. You're up against the cost of relatively inexpensive engines Vs flight rate Vs the cost of trained recovery crews, recovery equipment, recovery operations, inspection, re-certification, and re-integration of the engines. It would probably make more sense to re-design Stage 2 around the ITS paradigm than perform airborne helicopter recovery of second stage hardware.

Another factor is where do you carry this out? Normally second stages are disposed of in remote locations, but in this case you'd presumably need to make a deorbit burn that aims the stage for your engine recovery location. You don't ideally want it to be raining COPVs on a populated area, but doing helicopter recovery somewhere remote is going to add to the operation costs.
Waiting for joy and raptor

Offline drzerg

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Re: Landing an MVac
« Reply #41 on: 03/19/2017 09:10 AM »
possible solution is that after deorbit burn engine could detach from stage and make its own additional deorbit "burn" with cold gas from main nozzle. so they could be separated at the point of impact.

Offline Jim

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Re: Landing an MVac
« Reply #42 on: 03/19/2017 12:35 PM »
Not worth the effort

Offline Kaputnik

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Re: Landing an MVac
« Reply #43 on: 03/21/2017 06:27 AM »
possible solution is that after deorbit burn engine could detach from stage and make its own additional deorbit "burn" with cold gas from main nozzle. so they could be separated at the point of impact.


So you're now aiming for a steeper and harsher entry with the engine. And you've just added three axis control to your engine too (or else how do you make sure the extra deorbit burn is in the right direction?).

If you wanted to make this work, it might be better to do the deorbit burn, jettison the engine, but have the stage remain active to perform additional manoeuvres- remember it already has the avionics, thrusters, and propellant. Have it enter short of the engine recovery zone, as its higher ballistic coefficient will tend to do that anyway.

I still don't know if you can get enough separation to ensure safety, though.
Waiting for joy and raptor

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