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NASA Considers Apollo-Era F1 Engine For Space Launch System
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."
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.
"Tell me doctor, with all of your defenses, are there any provisions for an attack by killer bees?"
This is what I like about rocket engines. A rocket engine designed for a specific load in the 60s and today would have nearly the same design. A modernized F1 is entirely logical.
And before people complain about rocket engines not advancing at the same rate as microprocessors, let me note that the cost of a rocket is primarily determined by its complexity, not the cost of fuel or the size of the engines. A simple rocket engine (like the F1) that burns kerosene and oxygen is often cheaper than super advanced rocket engines like those on the Space Shuttle.
The F-1 wasn't a booster, it was an engine. The booster stage using the F-1 was the S-1C.
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Who is hauling all of our astronauts back and forth to the ISS right now? How old is their design?
There is a lot to be said for refining stable designs instead of starting over with a clean sheet of paper, back at the bottom of the learning curve.
I really wish I understood more about rocketry and satellites :/
This is true in many other fields as well. I really wish NASA understood more about rocketry and satellites.
Have gnu, will travel.
The F1 is a perfect example of a big dumb booster. 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.
Because it is good engineering practice to know what has been done before? We do not build things in a vacuum, but rather we build upon the successes and failures of others. By knowing what has failed in the past we can avoid those traps in the future and by knowing what has worked we can have a firm foundation upon which to improve.
>Why even study redesigning the F1?
Because it's the largest liquid fueled engine in existence, and it works. Nobody has anything comparable to it, not even the Russians. There's a reason why the Russians use so many smaller engines.
Why design from scratch when you have known working prototypes? Only fools reinvent the wheel. Indeed, going back and redesigning the "shower head" fuel injection plate would be just nuts as it works fabulously.
A lighter, more efficient F-1A would be really, really sweet.
--
BMO
Is there any reason we shouldn't recycle designs when it comes to rocket engines? Of course (maybe?) we could use modern tools to help improve efficiency but is there anything to gain by starting from scratch?
Unless you have some new form of rocket fuel or someone discovers a radical new design for an engine that improves efficiency, not really. Rockets are a pretty well established field: starting from scratch doesn't really happen. Not only would it add a ton of testing and design time (which costs quite a lot of money), but you aren't really even sure it would work any better. Rockets are, well, rockets. Ignite propellant, make sure it heads out the back. Thats a gross oversimplification, of course, but they aren't like jets that have a ton of thrust-creating parts you can redesign and recreate in different ways (turbojet, ramjet, scramjet, etc.)
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
Generally speaking, in rocket design, 'efficient' == 'expensive, temperamental, and hard to reuse'. Fuel is cheap, engines are expensive, so if you can throw more fuel at the problem you're usually better off than getting the last 10% efficiency out of the engine through complex design and materials.
The F-1 is actually quite crude by today's standards. It's not throttleable so the acceleration curve for a Saturn-V launch started off slow and picked up to about 4-Gs as the first stage's fuel ran out which beat up the crew somewhat. The Shuttle in comparison never exceeded 3-G. The F-1 has a low chamber pressure (70 bar) and reduced Isp (263 seconds) compared to modern LOX/RP-1 engines like the throttleable RD-180 (266 bar and 311 seconds) as used on the Atlas launcher.
Am I the only one who was wondering what NASA was going to be doing with a Cosworth DFV?
Saturn V wasn't used to boost large payloads to LEO with the exception of Skylab. False comparison.
Uh, what do you think an Apollo mission was?
One supposes that it might be economical if it's properly mass produced and not required to be man-rated.
Yes. Now perhaps you can explain where all these 150 ton payloads are that need a mass-produced heavy lifter that will, at least initially, cost billions of dollars per flight?
Hint: they don't exist. There's no budgeted payload for this launcher.
Wouldn't it be more cost effective for NASA to just use the upcoming SpaceX Merlin 2 engine? The design documents state that the Merlin 2 should provide 890 kN more thrust than the old F1 engine and should be much more efficient. Plus, the Merlin 2 has the benefit of being already in active development: SpaceX expects they'll have it ready for certification within 3 years.
The Saturn V was the most cost efficient heavy lift launch vehicle to fly. The cost per lb to LEO is only $9,915 which is cheaper than the Atlas V or the Ariane V. The Falcon 9 does beat it but then you have the other metric.
Saturn V 118,000 kg to LEO
Falcon 9 10,450 kg to LEO
Falcon Heavy 53,000 kg to LEO
And that was with 1960s support systems. NASA was working on an improved Saturn 5 and tested F-1a engines that where ligher, had more thrust, and a higher specific impulse than the ones flown in the Saturn 5. Take the F-1a and add modern electronics for control and build the stage using modern methods and materials and you could drop the costs.
What I fear is this is just a tactic to do nothing. If you keep studying the new launch system and changing it you will never have to build it. If you do not build it can never fail so you can never be blamed. As a politico it works well you can spend a ton of money doing studies to save money by finding a better way and when you have spent a lot you can kill the project because "they" have wasted all this money and have not built a thing.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
If NASA wants to break out the most powerful liquid fuel engines ever built, they need to go to Russia with their checkbooks again. At the end of the cold war, the Soviets ended up way ahead in liquid engine design - which can be attested to by the fact that many modern US launchers use Russian engines (RD-180, NK-33 soon) or designs which draw on Russian expertise (RS-68)
Because it's the largest liquid fueled engine in existence, and it works. Nobody has anything comparable to it, not even the Russians.
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 )
http://validator.w3.org/check?uri=http%3A%2F%2Fwww.slashdot.org Errors found while checking this document as HTML5!
What's up, snopes. Nice tall tale, though.
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
You're forgetting the F-1A.
The F1 was designed in 1959. The F1A is an improved version, which is what we're really talking about.
And the F1A has these stats:
Rocketdyne Lox/Kerosene rocket engine. 9189.6 kN. Study 1968. Designed for booster applications. Gas generator, pump-fed. Isp=310s.
Thrust (sl): 8,003.800 kN (1,799,326 lbf). Thrust (sl): 816,178 kgf. Engine: 8,098 kg (17,853 lb). Chamber Pressure: 70.00 bar. Area Ratio: 16. Propellant Formulation: Lox/RP-1. Thrust to Weight Ratio: 115.71.
Status: Study 1968.
Unfuelled mass: 8,098 kg (17,853 lb).
Height: 5.48 m (17.97 ft).
Diameter: 3.61 m (11.84 ft).
Thrust: 9,189.60 kN (2,065,904 lbf).
Specific impulse: 310 s.
Specific impulse sea level: 270 s.
Burn time: 158 s.
First Launch: 1967.
Source: http://www.astronautix.com/engines/f1a.htm
The RD-170 has these stats:
Chambers: 4. Thrust (sl): 7,550.000 kN (1,697,300 lbf). Thrust (sl): 769,876 kgf. Engine: 9,750 kg (21,490 lb). Chamber Pressure: 245.00 bar. Area Ratio: 36.87. Thrust to Weight Ratio: 82.66. Oxidizer to Fuel Ratio: 2.6.
AKA: 11D520.
Status: Development ended 1976.
Unfuelled mass: 9,750 kg (21,490 lb).
Height: 3.78 m (12.40 ft).
Diameter: 4.02 m (13.17 ft).
Thrust: 7,903.00 kN (1,776,665 lbf).
Specific impulse: 337 s.
Specific impulse sea level: 309 s.
Burn time: 150 s.
First Launch: 1981-93.
Number: 12 .
Source: http://www.astronautix.com/engines/rd170.htm
Chest thumping? I think not.
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BMO
Yes
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
Von Braun didn't either but instead worked around it, which was possible using several engines instead of relying on continuous output from a single engine. The F-1 bounced around all over the place, but that was known behaviour.
Saturn V wasn't used to boost large payloads to LEO
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.
Make me a friend and I'll mod you up
LEO is on the way to the moon. The Saturn V delivered to LEO a payload consisting of the Command and Service Module, the Lunar Module, and a booster with enough fuel to put all of the above on a lunar trajectory. You could replace all of this with any arbitrary payload of equal weight and the Saturn V would be able to put it into LEO.
Make me a friend and I'll mod you up
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.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger