Watch Very Cool Video of a Hot Engine
Written by Nancy Atkinson
The Common Extensible Cryogenic Engine, or CECE. Image Credit: Pratt & Whitney Rocketdyne
Yes, you're seeing this image correctly. There are icicles forming at the rim of this rocket engine bell, and this particular engine generates a scalding 2,760 C (5,000 F) degree steam and a whopping 13,000 lbs of thrust. How can that happen? Cryogenics. NASA is developing the engines that will be used for the next generation lunar lander, the Altair. These engines are called the Common Extensible Cryogenic Engine (CECE). CECE is fueled by a mixture of -182 C (-297 F) liquid oxygen and -253 C (-423 F) liquid hydrogen. The engine components are super-cooled to similar low temperatures–and that's where the icicles come from. As CECE burns its frigid fuels, hot steam and other gases are propelled out the nozzle. The steam is cooled by the cold nozzle, condensing and eventually freezing to form icicles around the rim. Watch the video.
More about the engine.
CECE, is a deep-throttling engine, which means it has the flexibility to reduce thrust from 100 percent down to 10 percent — allowing a spacecraft to gently land on the lunar surface. During the test, the engine was successfully throttled from a high of 104 percent of the engine's potential down to eight percent, a record for an engine of this type. A cryogenic engine is needed to provide high performance and put more payload on the surface of the moon. The CECE demonstrator has evaluated two engine configurations during three rounds of hot-fire testing.
The tests are being done by Pratt & Whitney Rocketdyne in West Palm Beach, Florida. This was the third test for these engines. Previous tests in 2006 and 2007 showed the engines needed some fine tuning. Tony Kim, Deep Throttling Engine project manager at NASA's Marshall Space Flight Center, Huntsville, Ala, said, "Testing in 2007 provided an in-depth examination of low-power-level throttling and engine performance characteristics. This third cycle we actively addressed and found solutions to the challenges we faced."
The team carefully assessed test results that showed pressure oscillations in the engine at lower throttle levels called "chugging." Chugging may not be a concern for the engine itself, but the resulting vibrations could have the potential to resonate with the structure of the rocket and cause problems for the lander or crew.
Injector and propellant feed system modifications successfully eliminated engine chugging by controlling liquid hydrogen and liquid oxygen flow to the combustion chamber. The latest engine configuration incorporates a new injector design and propellant feed system that carefully manages the pressure, temperature and flow of propellants. And it seemed to work quite well.
Cool!
Source: NASA
Filed under: Constellation, Space Flight
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January 15th, 2009 at 10:09 am
That's so cool.
Literally.
January 15th, 2009 at 11:27 am
How do you get 104 percent of an engine's potential? Isn't that like eating 104 grams of a 100 gram chop? Where do the extra 4 grams come from?
I was under the impression that all engines always worked under their potential. No?
January 15th, 2009 at 12:04 pm
@ Jorge:
My guess is they estimated the engine was only so powerful, but under testing they found that it actually went above what they had predicted.
January 15th, 2009 at 12:30 pm
@Jorge:
The engine's rated capacity is lower than it's absolute capacity. It is generally the difference between the 'safe' maximum and the mechanical maximum.
January 15th, 2009 at 12:56 pm
Ah. I see. Thanks for clearing this up for me.
January 15th, 2009 at 12:57 pm
That was awesome. Ive got to get me one
January 15th, 2009 at 2:06 pm
Actually, when space shuttle pilots hear "Go at throttle up", it means they have passed max q and the main engines are going to throttle from 65% to 104%…
January 15th, 2009 at 5:12 pm
This is sweet, but would the fact that engine components need to be kept at cryogenic temperatures limit it to extra-atmospheric use?
January 15th, 2009 at 5:40 pm
Windows Media Player – I am so sick of the U.S. Government using my tax dollars to sanction microcrap corporation.
January 15th, 2009 at 5:41 pm
I think the point is that it's an engine designed for the hardships of space. A place where hot and cold simply don't work in the ways we landsiders are used to.
January 16th, 2009 at 12:37 am
Linux — use VLC, is plays .asx files just fine and it's GNU GPL
January 16th, 2009 at 3:17 pm
"This is sweet, but would the fact that engine components need to be kept at cryogenic temperatures limit it to extra-atmospheric use?"
Not really. The Space Shuttle Main Engine (SSME) is also a hydrogen-oxygen burner, as are the engines in the Delta IV first stage. (and many other rockets use liquid oxygen as the oxidizer, which is still pretty cold stuff, though not so much as liquid hydrogen)
And the CECE is a modified RL-10, the first production LOX/H2 engine, first designed in the early 1960s for the Centaur upper stage. A throttleable version, modified for sea-level operatios was also used in the DC-X program to test single stage to orbit technologies…
http://en.wikipedia.org/wiki/RL-10
I had always hoped that the Centaur/RL-10 might one day be modified into a reuseable orbit-to-orbit space tug, including a Lunar landing capability..I may yet sort of get my wish.
January 16th, 2009 at 8:39 pm
Boy pretty scary choice to use complex cryogenics for landing on the moon. There is a reason storables were used last time, with an ultra simple engine… We dont want people stranded on the moon or to have them crash land.
January 17th, 2009 at 5:48 pm
My amp goes to 11.
January 20th, 2009 at 7:54 pm
If engines of this type have to be sensitivly watched on earth at our tepid temps, do you think they would react to the coldest temps, on cold planets, the same way on the cold gas giants like saturn or jupiter? Cold engines work better in cold environments? Make them operate not here but on the cold saturns or their moons. I feel they would get better results there. (On cold atmospheric planets). Start at the Antarctic and find out.
January 26th, 2009 at 11:13 pm
Its kinda weird to use this kind of technology for jet propulsion but i guess it works so be it.
March 20th, 2009 at 5:26 am
Does anybody know what's the difference between this CECE and SSME which Space Shuttle use? Both use liquid oxygen and hydrogen, both have cooled nozzle etc…