Author Topic: Recovering the core stage engines Vulcan style?  (Read 2143 times)

Offline Caleb Cattuzzo

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So I recently saw the concept for recovering of the ULA's Vulcan 1st stage engines and I was wondering if this theoretically with alot of design overhauls be used with SLS but without the whole catching in mid-air part I think RS-25's are too heavy for a helo.Or could it be possible to splash-down the whole core stage like this concept for the saturn?
There is no strife,no prejudice,no national conflict in space as yet.Its hazards are hostile to us all.

Offline envy887

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Re: Recovering the core stage engines Vulcan style?
« Reply #1 on: 03/22/2018 11:10 PM »
The SLS core is much more like the S-II than the S-IC, in terms of entry velocity, downrange distance, and payload reduction for recovery systems.

The engine section will be in the 20+ tonne range, well beyond the capacity of a helicopter catch.

Online speedevil

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Re: Recovering the core stage engines Vulcan style?
« Reply #2 on: 03/22/2018 11:19 PM »
The engine section will be in the 20+ tonne range, well beyond the capacity of a helicopter catch.
But, quite within the landing capabilities of a block 5 F9S1 with a grabber on top.

(no, not really).

Changing SLS enough to make it partially recoverable at this late stage in construction would delay everything so hideously it's really probably not worth it, even if you could magically recover the engines via teleportation.

Offline Ronsmytheiii

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Re: Recovering the core stage engines Vulcan style?
« Reply #3 on: 03/24/2018 09:42 AM »
The engine section will be in the 20+ tonne range, well beyond the capacity of a helicopter catch.

Well maybe they could build a larger version of SpaceX's FSV...... Dr Steven

The idea isn't crazy as it seems. In Boeings original EELV proposal (Delta IV was McDonald Douglas before Boeing bought them out) they were going to use an SSME powered stage, where the engines would separate in a pod to be recovered:

https://www.globalsecurity.org/space/systems/eelv_b.htm

Edit:Looks like the engines would splashdown, and be recovered in a watertight pod:

https://web.archive.org/web/19961223013527/http://www.boeing.com/news.release.960827a.html
« Last Edit: 03/24/2018 09:46 AM by Ronsmytheiii »
And this is a good reminder that just because one of your fellow space enthusiasts occasionally voices doubts about the SpaceX schedule announcements or is cautious about believing SpaceX has licked a problem before actually seeing proof that's true, it doesn't mean they hate SpaceX.

Offline Steven Pietrobon

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Re: Recovering the core stage engines Vulcan style?
« Reply #4 on: 03/25/2018 05:14 AM »
Well maybe they could build a larger version of SpaceX's FSV...... Dr Steven

Assuming FSV = First Stage Vehicle, I've had a quick look at replacing the core and two boosters with a kerolox stage using 19 AR-1 engines. Thrust would be 42.3 MN with 2724.3 t of propellant and dry mass of 152.7 t. The new stage has 8.92 GNs of impulse compared to 7.53 GNs for the SLS core and boosters, an 18% increase to help make up for reduced Isp of kerolox compared to hydrolox. I'm not confident though that would be enough without doing some further calculations. Adding fins and legs to the stage would then make it reusable. Here's what the engine arrangement would look like. (Thanks to http://hydra.nat.uni-magdeburg.de/packing/cci/cci19.html )
« Last Edit: 03/25/2018 05:14 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline envy887

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Re: Recovering the core stage engines Vulcan style?
« Reply #5 on: 03/25/2018 12:23 PM »
Well maybe they could build a larger version of SpaceX's FSV...... Dr Steven

Assuming FSV = First Stage Vehicle, I've had a quick look at replacing the core and two boosters with a kerolox stage using 19 AR-1 engines. Thrust would be 42.3 MN with 2724.3 t of propellant and dry mass of 152.7 t. The new stage has 8.92 GNs of impulse compared to 7.53 GNs for the SLS core and boosters, an 18% increase to help make up for reduced Isp of kerolox compared to hydrolox. I'm not confident though that would be enough without doing some further calculations. Adding fins and legs to the stage would then make it reusable. Here's what the engine arrangement would look like. (Thanks to http://hydra.nat.uni-magdeburg.de/packing/cci/cci19.html )
it
I'm sure Ron was referring to the SpaceX Fast Service Vessel, Mr Steven.

However, your contributions are as always very useful, Dr Steven.

The main problem with this type of booster is the lack of a upper stage suitable for the low staging velocity required for booster reuse. With an S-II it could lift 120 tonnes to LEO with booster RTLS.

Offline Mark S

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Re: Recovering the core stage engines Vulcan style?
« Reply #6 on: 03/25/2018 04:35 PM »
It seems to me that the only way to make the SLS core stage re-usable, while also keeping it an SLS core stage, would be to add a couple of J2X engines to the four existing RS25 engines. They burn the same fuel, have good ISP, and are re-startable for the boost-back, re-entry, and landing burns. That would enable the core to perform a SpaceX-type vertical landing recovery of the stage.

Of course the landing gear would be massive, and the performance impact might be prohibitive. But at least it should be physically possible.

As with SpaceX, since the cores would be disposed of anyway, what is the harm in trying? If it works, great. If it takes a few tries to get it right, so be it. At least NASA would be showing that they are not being intentionally wasteful of taxpayers money. And if the cores could be re-used, that would free up a ton of money for additional missions or other hardware (e.g. payloads).

If you stick with saving just the engine section, and ditch the tanks, then the recovery and landing engine could be much smaller. Say maybe a single MB-60 or a couple of RL-10s. But with the core tanks gone, they would needed dedicated recovery propellant tanks that are integrated with the engine pod. Not so simple. But at least the landing gear could be much smaller.


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