NASA Considers Apollo-Era F1 Engine For Space Launch System 197
MarkWhittington writes "A company named Dynetics, in partnership with Pratt & Whitney Rocketdyne, will perform a study contract for NASA to explore whether a modern version of the Saturn V F1 booster (PDF) could be used on the Space Launch System. These would be the basis for a liquid fueled rocket that would enhance the SLS to make it capable of launching 130 metric tons to low Earth orbit, thus making it capable of supporting deep space exploration missions in the 2020s."
Oh man... (Score:5, Insightful)
I would LOVE to see the F1 back in action. Few things have inspired such awe in me as the launch of a Saturn V rocket and the five tremendous columns of fire atop which it strode.
Seems like a tremendous waste (Score:3, Insightful)
The F1 was designed on blackboards and drafting tables. A "modern" F1 is only going to be similar in size - it'd have to be a clean sheet design, the facilities that built the F1 are long gone at this point. Why even study redesigning the F1? This seems like a tremendous waste. Of course it's going to be a clean sheet, computer drafted design.
Money for a study on a stone age rocket design* seems like a federal handout, nothing more.
*although the Saturn V's anti-oscillation system is pretty inspired... for it's time
Re:Seems like a tremendous waste (Score:5, Insightful)
The F1 is a perfect example of a big dumb booster [wikipedia.org]. It is cheap, especially so if you mass produce it. The Space Shuttle Main Engines are examples of non-stone age rocket design that uses advanced materials and tries to be reusable. Guess which one is cheaper to operate?
Here's a hint: the Russians like big dumb boosters for a reason.
Re:Seems like a tremendous waste (Score:5, Insightful)
Re:Seems like a tremendous waste (Score:4, Insightful)
Why let facts get in the way of perfectly good chest thumping, huh ? RD-170, the engine that lifted Polyus and Buran with Energia rocket, and its derivative is powering Zenit rockets today, has higher thrust than F-1 had ( past tense )
Re:The Best or Cheapest Option? (Score:5, Insightful)
Yeahbut....we wouldn't be basing the new F-1 type engine on the original F-1, we'd be using the F-1A.
The F-1A has 33 percent more thrust than the F-1.
9,189.60 kN for the F-1A versus 7,887 kN for the RD-171
But here is where the real difference comes in:
Lox/RP-1. Thrust to Weight Ratio: 115.71. for the F-1A
It's 82 for your Russian motor. Thus the advantage of using one combustion chamber compared to using 4.
Modern materials should lighten the F-1A and modern controls should improve efficiency and thrust even more to improve the thrust to weight ratio.
Why the Russians never use large combustion chambers and why you see 4 of them on the RD-171: They never solved the problem of combustion instability beyond a certain size. We did.
--
BMO
Re:Rocket engines (Score:3, Insightful)
Re:Seems like a tremendous waste (Score:5, Insightful)
On a lunar mission, the Saturn V would put the Command and Service Module, the Lunar Module, and a booster with enough fuel to put them both on a lunar trajectory, into LEO. That's a pretty damn large payload, the largest payload to LEO of any single vehicle ever produced. The fact that the payload eventually boosted itself the rest of the way to the moon isn't relevant to the vehicle's ability to put mass into LEO.
It is the nature of rocketry that any small mass in a high orbit will tend to get there by going through a period in which it is a large mass in a lower orbit. In a staged rocket, it is useful to think of each stage as its own vehicle, with all of the stages above it as its payload which it is capable of delivering to a certain point.
Re:Total n00b here (Score:4, Insightful)
Lastly, why couldn't they build a huge engine and de rate it to obtain reliability?
ppanon's answer is mostly correct, but the main problem is the relationship between reliability and performance is strongly non-linear. Dropping performance by 50% might only increase safety by 0.1%.
Very crude example using made up numbers is you drop turbopump RPMs by half and run the mixture ridiculously rich so it looks like a candle flame and drop chamber pressure to half what it was. On one side you just zapped maybe 90% of performance, easily meeting that goal. The problem is the turbopump is only about 0.001% more reliable because its still spinning at 50K RPM, the lower chamber pressure and impaired mixture means lower combustion temp means its only dull red instead of bright red, etc.
A crude /. car analogy is flooring an engine and dyno testing it is pretty hard on the engine, even if you intentionally detune the engine a bit. It fact if you detune it to the point of backfiring and pinging its much worse for it.
Another issue that no one likes to discuss is the chamber and nozzle acoustic model is designed for a certain set of conditions and flow rate. You kinda have to start over again if you derate. You can run over a wide range if you're willing to trade efficiency, but... You don't want to crank down the injection pressure, resulting in a lower delta p across the injectors, resulting in a screamer or chugger blowing the thing to pieces.
Then another thing is your exhaust "bell" part of the nozzle is designed for a certain flow rate delta p and exhaust pressure. Drop the pressure enough and you can supposedly get the nozzle to collapse in on itself. Also where the flow separates inside the nozzle has pretty serious thermal and mechanical problems.
So you need a new set of acoustic tests and probably chamber fixes, and a new injector design, and a new nozzle, probably new turbopumps... So you get to keep ... I donno ... the chamber and mounting arms I guess. It seems a lot faster simpler and cheaper if you have a 100 Kpound thrust engine and you need a 10 Kpound thrust engine to simply sell the 100K for whatever you can get and buy an off the shelf 10K design.