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General Discussion => Advanced Concepts => Topic started by: spacetech on 12/31/2013 07:23 PM

Title: Launch Escape System for aborting satellite launch?
Post by: spacetech on 12/31/2013 07:23 PM
with the high cost of some commercial satellites I'm wondering would it be worth putting an Apollo style Launch Escape Tower integrated into the payload fairing so that if the launch vehicle fails during launch or staging, they can recover the satellite intact using a propulsive landing.

Of course, if the technology is advanced enough to allow for a propulsive landing you'd hope the launcher has a very low mission failure rate. An alternative would possibly be use the F9R 2nd stage to pull the satellite away if the F9 1st stage fails.
Title: Re: Launch Escape System for aborting satellite launch?
Post by: Jim on 12/31/2013 07:38 PM
with the high cost of some commercial satellites I'm wondering would it be worth putting an Apollo style Launch Escape Tower integrated into the payload fairing so that if the launch vehicle fails during launch or staging, they can recover the satellite intact using a propulsive landing.

Of course, if the technology is advanced enough to allow for a propulsive landing you'd hope the launcher has a very low mission failure rate. An alternative would possibly be use the F9R 2nd stage to pull the satellite away if the F9 1st stage fails.

There are many threads on this and the short answer is that it is not worth it.  Here are the show stoppers:

abort accel loads
Water landing
landing loads
control of the spacecraft
fairing environment

Current spacecraft are not designed for these.

Title: Re: Launch Escape System for aborting satellite launch?
Post by: Andrew_W on 01/01/2014 06:11 PM
You'd have to mount the satellite inside a dragon like capsule, a huge weight penalty.
Title: Re: Launch Escape System for aborting satellite launch?
Post by: imspacy on 01/02/2014 12:30 AM
You'd have to mount the satellite inside a dragon like capsule, a huge weight penalty.

I don't see why payload shrouds couldn't be engineered include some rocket/parachute capability for 'payload launch failure recovery'... watertight.. with a substantial launch weight increase, of course..
The pain/cost/utility of the 'huge weight penalty' depends completely on the cost per pound to orbit...
If you're launching a legacy type EELV booster like Delta/Atlas/SLS, costing $5,000 or more per pound payload to orbit, then paying for say a 10,000lb 'payload launch failure recovery capability' is prohibitive... $50m...
However, if you're launching on a $500/lb to LEO booster like Falcon Heavy-R, then paying for a 10k lb payload launch failure recovery capability for a $100m payload becomes affordable and justified... $5m...

BTW, the same overriding cost per lb to leo applies to many other aspects of satellite/mission design... if payload lbs to LEO is cheap, then additional functionality, endurance, fuel, etc can be added, cheaper/heavier construction methods and materials used, etc..

Cost per lb/leo is key... that's why the order of magnitude SpaceX Falcon, Falcon Heavy, and Falcon reusable launch efficiencies are such a breakthrough.
Title: Re: Launch Escape System for aborting satellite launch?
Post by: Jim on 01/02/2014 12:36 AM
I don't see why payload shrouds couldn't be engineered include some rocket/parachute capability for 'payload launch failure recovery'... watertight.. with a substantial launch weight increase, of course..


That is why you are only a poster.  Others do see the reasons.
It is more than substantial, but a prohibited weight increase .
Also, there is a massive weight increase for the payload structure to take the abort and landings loads. 
It is a non starter, just like parachutes for airline passengers
Title: Re: Launch Escape System for aborting satellite launch?
Post by: Jim on 01/02/2014 12:39 AM

Cost per lb/leo is key... that's why the order of magnitude SpaceX Falcon, Falcon Heavy, and Falcon reusable launch efficiencies are such a breakthrough.

Nonsense, the breakthrough hasn't happened.  It is not even 1/2 much less a magnitude.   
Title: Re: Launch Escape System for aborting satellite launch?
Post by: ANTIcarrot on 01/02/2014 09:41 PM
For certain LOM situations though, there is an 'escape' option. If an upper stage fails (or prematurely shuts down) then onboard RCS fuel can be used as a 'bonus stage' to move the satellite into a more stable or more useful orbit. This is obviously a trade off against lifespan. It's also undesirable to move into an orbit that might decay in a 'dangerous' manner. You really want to have enough RCS left over for a controlled entry. For legal reasons if nothing else.

RCS systems are moving slowly towards various high efficiency electrical designs. Once these are more mature, we might get to the point where the marginal mass/cost increase of a larger RCS tank is mitigated by a slightly lower launch insurance premium. The eventual development of a notional light/cheep fuel-transfer docking collar might encourage this further.

Title: Re: Launch Escape System for aborting satellite launch?
Post by: Jim on 01/02/2014 09:53 PM

RCS systems are moving slowly towards various high efficiency electrical designs. Once these are more mature, we might get to the point where the marginal mass/cost increase of a larger RCS tank is mitigated by a slightly lower launch insurance premium. The eventual development of a notional light/cheep fuel-transfer docking collar might encourage this further.


Not during launch.  Low thrust does no good.  And the larger RCS vs premium makes no sense.   The company is going to want a certain orbital lifetime based in the tank size. A larger tank just means a longer lifetime.
Title: Re: Launch Escape System for aborting satellite launch?
Post by: Jim on 01/02/2014 10:02 PM
For certain LOM situations though, there is an 'escape' option. If an upper stage fails (or prematurely shuts down) then onboard RCS fuel can be used as a 'bonus stage' to move the satellite into a more stable or more useful orbit. This is obviously a trade off against lifespan. It's also undesirable to move into an orbit that might decay in a 'dangerous' manner. You really want to have enough RCS left over for a controlled entry. For legal reasons if nothing else.


That is not defined as an LOM situation
Title: Re: Launch Escape System for aborting satellite launch?
Post by: hop on 01/02/2014 10:45 PM
I don't see why payload shrouds couldn't be engineered include some rocket/parachute capability for 'payload launch failure recovery'... watertight.. with a substantial launch weight increase, of course..
The question isn't whether it could be engineered, of course it could. The relevant question is whether the cost is worth it.

Current top-end LVs fail something like 1%-2% of the time, and only some failures would  be saved by a recovery system. You pay the cost of the recovery system whether or not you use it, and if you do use it, you still spend a bunch of money re-certifying the payload and replacing the launcher. That ends up being a lot of money you could spend on assuring success in other ways, like building backup payloads or buying insurance.

If the payloads are worth $1 billion, and recovery saves you 1% of your launches, the total cost of the recovery system has to be under $10 million. This doesn't pass the giggle test. A re-entry vehicle capable of returning a multi-ton payload would cost more than that all by itself. The mass of the recovery system would require you to buy a much bigger launcher (again eating > $10 million), and a payload engineered to survive recovery would also be more costly and more massive.

Spending the money on insurance is starting to look like a pretty good alternative...
Title: Re: Launch Escape System for aborting satellite launch?
Post by: savuporo on 01/02/2014 10:55 PM
Current top-end LVs fail something like 1%-2% of the time, and only some failures would  be saved by a recovery system. ..
Spending the money on insurance is starting to look like a pretty good alternative...
And thats exactly why insurance was invented, and if you think about it, this entire save my payload engineering would be just trying to lower your insurance costs not eliminate it.

How much are the insurance premiums for astronauts, anyway ?