I have got to get me one of these:
A NASA contractor has built a test engine that runs on methane. That image is from a movie of the test firing, and yes, you want to see it. Make sure the sound is turned up.
So so cool.
Methane is a pretty good fuel. For one thing, it doesn’t have to be kept as cold as other fuels, making it easier to make and use. You don’t need such thick tanks for it, which saves weight, and it’s a safe substance (a spill wouldn’t be all that toxic). The linked article about this is pretty informative, but one thing it doesn’t have is the comparative thrust of methane versus, say, what’s being used now on expendable rockets. If the bang isn’t worth the saving in bucks then it hardly matters. This particular engine had a 7500 pound thrust, which is nice, but compare that to the 100,000 pound thrust of the GEM-40 (used on Delta II rockets) — and bearing in mind that several GEM-40s may be strapped on to a rocket — and you can see there’s a ways to go yet. Still, it’s early in the game, and this was a test of a small version. I’m sure they’ll get bigger!
And when they do get bigger, and can be used for solar system exploration, there’s another advantage that kicks in: methane can be found all throughout the solar system (or made easily from available materials). That means you don’t have to carry all your fuel around with you! If you go to Mars, or Saturn’s moon Titan, you can bring enough fuel to get there, then make the rest from the planet you’re sitting on (and please, no astronaut diaper or related jokes!). That saving in weight is HUGE, and a very big plus.
And also, really just how frackin’ cool is that video? Wow.
May 7th, 2007 at 8:04 pm
[...] to blog about (of which only one or two actually get blogged about ), but of course the BABlogger beat me to the punch. Then again, that is sorta his [...]
May 7th, 2007 at 8:12 pm
Wow is right. I’m impressed. Loud isn’t it? (Nice bass note too.) I can really imagine future propulsion applications.
May 7th, 2007 at 8:14 pm
Oh, man. That video is so hot this post should be labelled NSFW.
May 7th, 2007 at 8:17 pm
Neat video, that looks like a pretty small testbed actually so it will be neat to see how well it scales up.
Non-rocket scientist question….what makes those pretty diamonds in rocket exhaust? I’m guessing something along the lines of shock waves in the exhaust but I got no clue.
May 7th, 2007 at 8:33 pm
[insert immature fart joke]
I was wondering about the pattern in the exhaust as well. Looks really cool.
May 7th, 2007 at 9:02 pm
I am in trouble.
When I was watching this (have seen it before on another blog) here, I began to think of TREMORS, movie #3, I think, where the graboids mutate into @$$blasters.
Yeah, and I have Kaiju movies,too.
J/P=?
May 7th, 2007 at 9:08 pm
Non-rocket scientist question….what makes those pretty diamonds in rocket exhaust?
Mach diamonds (something visible when the Shuttle lifts off, too).
Description/explanation here:
http://en.wikipedia.org/wiki/Mach_diamond
May 7th, 2007 at 9:13 pm
It’s been a long time since I studied that, but yes, I recall those patterns being related to pressure-related standing waves in the exhaust or some similar effect. If it wasn’t 1 AM on a work night, I’d probably be able to give a better answer.
Right now, somewhere, there is a kid dreaming about strapping that puppy onto his car
May 7th, 2007 at 9:14 pm
Well there you go. Thanks Remek
Cool picture in the wiki too.
May 7th, 2007 at 9:15 pm
Very cool, but when asked how they got the idea, an engineer responded “I just pulled it out of my butt”.
Couldn’t resist.
One word changed by The Bad Astronomer.
May 7th, 2007 at 9:19 pm
Off topic, I went to a P&W father-son day event once, and I remember seeing a J-58 on a test pad, just sitting there without any cladding. It looked like a rocket about to take off. Just a huge mass of potential thrust, I think that even a traveller from the past would look at it and say “that thing has got to be hella-fast”.
May 7th, 2007 at 9:41 pm
[quote=Jay]May 7th, 2007 at 8:33 pm
[insert immature fart joke][/quote]
COW [s]FARTS[/s] belching RULES! I wonder if that rocket smells?
ah but 95% of bovine methane emissions come by the way of belching not flatulence
May 7th, 2007 at 9:43 pm
opss vB Code code doesn’t work, doh!
anyways…
May 7th, 2007 at 9:54 pm
[quote]
The linked article about this is pretty informative, but one thing it doesn’t have is the comparative thrust of methane versus, say, what’s being used now on expendable rockets. If the bang isn’t worth the saving in bucks then it hardly matters.
[/quote]
Not true! The really cool thing about a methane rocket is that you can refuel it from an icy moon or comet. If you are going to Mars, you just need to bring along a relatively small quantity of hydrogen, react it with atmospheric CO2, and you have methane for exploration and/or the trip home.
May 7th, 2007 at 11:21 pm
If methane is burned stoichiometricly, you’d need four times as much oxygen
(by mass):
CH4 + 2 O2 –> CO2 + 2 H2O
So I doubt one would bother carrying all the oxygen and extracting the methane from a celestial body.
Robert Zubrin (you may bump into him in Colorado) advocates the idea of carrying hydrogen to mars and using the ambient CO2 to manufacture CH4 and O2 using a portable power station (be it nuclear or solar) for energy input.
May 8th, 2007 at 1:28 am
Quote:
“Methane has so many advantages,” continues Tramel. “The question is, why haven’t we done this before?”
Maybe the exhaust velocity. Does anyone know what it is? Of course, the savings in fuel tank material and the added safety (plus the ease of gathering more mid-mission) could offset that.
May 8th, 2007 at 1:49 am
Yes, very, very cool!
)
May 8th, 2007 at 3:01 am
Wow!!! That was nuts!
I want one for my car.
May 8th, 2007 at 4:07 am
It occurs to me that strapping one of these to a car would be extremely dangerous because there are so many other cars not so equipped on the road. However, if you could mount one on say, a Vespa, you could manuever around all those other cars! Of course with my luck, I would be launched like Wile Coyote and end up as a headline in the local paper, “Local man flies across metro area. Ghastly impact results!”.
Seriously tho, This is a very cool development. I read a sci-fi story where this group of pilot/astronauts had the dangerous duty of dipping down into Jupiters atmosphere to collect Hydrogen and Methane. Somewhat like firefighting aircraft do today on local lakes. I wonder if we will ever become that sophisticated? Maybe we’ll have the chance if we can figure out how to survive AGW, huh?
May 8th, 2007 at 4:34 am
Tramel/zeb-
The performance of methane is OK when compared to other liquids directly, but the tradeoff of smaller tank size (compared to hydrogen) and accordingly lighter mass makes the comparison much better. This web page compares the basic specific impulse (exhaust velocity/9.8 m/sec) and the density impulse:
http://www.braeunig.us/space/propel.htm
The specific impulses of all the fuels compared seem low, but they’re compared at sea level, which would be a worst case.
Methane wasn’t flown before because kerosene is even easier to handle (liquid at room temperature), and the real payoff for methane comes when you start considering refueling ‘out there’, which wasn’t something we were looking in to early on in the space age.
May 8th, 2007 at 5:16 am
Must… resist… Uranus joke…. :gasp:
May 8th, 2007 at 6:08 am
Thomas beat me to it but yes, the implication is obvious – Cow powered spaceflight! Wisconsin will be the new leader in interplanetary travel. http://wistechnology.com/article.php?id=3203
May 8th, 2007 at 7:08 am
My favourite propellant idea is from an old Azimov story – ice (in “The Martian Way”). Of course, he assumed that we’d have handy little nuclear reactors to vaporise it, but it’s still a neat idea…
May 8th, 2007 at 7:29 am
Le Pétomane would be proud! He employed methane in his stage act, so to speak.
http://en.wikipedia.org/wiki/Le_P%C3%A9tomane
May 8th, 2007 at 8:39 am
Poul Anderson had a story that used the fermentation of beer as a propellant source.
May 8th, 2007 at 9:01 am
When I was at NASA in the 60’s they nwere constantly testing the Saturn 5 engine just outside of town. It was like being in a small earthquake. I went to see one of the test firings. The loudst thing I have ever heard and very impressive
May 8th, 2007 at 9:08 am
From Zeb,
“Maybe the exhaust velocity. Does anyone know what it is?”
Methane using LOX as an oxidizer has an exhaust velocity of 3615 Ns/Kg in a vacuum.
For LOX and RP1 the Ve is 3510 Ns/Kg again in a vacuum.
These come from Wikipedia on this page,
http://en.wikipedia.org/wiki/Liquid_rocket_propellants
BTW does anyone know how to convert from the data on this page to specific impulse, I’ve always found that to be a much more telling figure for the overall usefulness of an engine in space.
May 8th, 2007 at 9:40 am
Someone might have said this already, but those standing waves in the exhaust look cool as all getout.
May 8th, 2007 at 9:57 am
Look at that photo again, that’s no rocket engine, it’s a death ray!
May 8th, 2007 at 10:17 am
[...] from Bad Astronomy we have news of testing a Methane Engine. The picture looks CGI, but it’s [...]
May 8th, 2007 at 10:18 am
After thinking about it, this engine would be extremely beneficial, despite the lower exhaust velocity. You would only have to bring enough fuel for a one-way trip (and for the trip back you would need less fuel since Mars has a smaller gravity well to get out of).
May 8th, 2007 at 11:09 am
RayCeeYa-
Divide the velocity by 9.8 m/sec2 to get Isp. (Methane/LOX = 368 by your numbers)
May 8th, 2007 at 11:11 am
Alan E. Nourse wrote a story in the 1950s called “Trouble on Titan”. As I recall, one of the main characters had a “backwards” jet aircraft — it carried oxygen and pulled its methane fuel out of the atmosphere of Titan, instead of carrying fuel and breathing in the oxidizer. About the only thing I remember from the book, having last read it in Junior High about 40 years ago.
Seriously cool video.
May 8th, 2007 at 11:32 am
Here is another interesting use of hydrocarbons and propulsion technology:
http://www.asciimation.co.nz/beer/
May 8th, 2007 at 12:03 pm
You’d get something like 20% higher exhaust speed by burning hydrogen.
However, the boiling point of hydrogen is only 14 kelvins versus 110 for methane (around one atmosphere). Hydrogen also has very low density (71 grams per liter versus 424 grams per liter for methane).
May 8th, 2007 at 12:37 pm
Wow, those NASA photoshop conspirator guys are getting into hi-def video now? How cool is that?
I hope it’s obvious that I’m kidding.
The high quality of the photography and sound recording tells me they are finally hiring professionals to make this stuff look and sound as cool as it is.
Definitely something we should be glad of. I look forward to seeing more of this!
May 8th, 2007 at 1:54 pm
Some of the people responding to this article seem to be equating methane, 100% CH4, with biogas which contains from 30% CH4 to 70% CH4 with the rest primarily CO2 and small traces of clorinated hydrocarbons (landfill biogas) and from 30ppm H2S (landfill biogas) to 500ppm H2S (human sewage digester biogas) to 3000ppm H2S (pig manure digester biogas). Why would anyone want to haul such a low calorific density gas into space? We have to use it in situ in the biogas industry (boilers, engine-generators) since it isn’t commercially viable to compress it or worse yet, to liquify it for transportation.
May 8th, 2007 at 2:17 pm
Actually it looks crap on my work computer. Can’t wait to get it home!
May 8th, 2007 at 6:03 pm
As far as getting methane from places like Titan and Jupiter. I’ve always thought it was interesting that in cases such as that where you have a reducing atmosphere you need to bring along and manufacture your oxidizer. In our oxidizing atmosphere we take for granted that there is plenty of oxygen out there to act as the ultimate accepter of electrons after we burn fuel so the quest for fuel is paramount. On Titan or Jupiter the fuel is free you have to go to heroic methods to get your oxidizer. For example a Bunsen burner on Jupiter you’d hook up to the oxygen and adjust the ‘air’ as your methane source.
Of course when we fly into space out of the atmosphere I suspect that the oxidizer (liquid oxygen in many cases) is once again the harder thing to manufacture than the reducer, but for us sea level dwellers abundant methane seems like a free lunch when in fact it isn’t.
May 8th, 2007 at 6:38 pm
Methane rocket…
This is about 100 different kinds of cool. Click the picture to go to the NASA web site. There you can play the video of a test firing of a new methane-fuelled rocket. It works best if you can crank…
May 8th, 2007 at 7:39 pm
[...] – NASA tests a methane engine “…when they do get bigger, and can be used for solar system exploration, there’s [...]
May 9th, 2007 at 7:19 am
Cool. Another bloody chemical powered reaction device.
I have no use for these “improvements”. Low specific thrust, Very large volume storage tanks, low payload capacity.
When will we have nuke powered space craft???
Think about it,,,
GAry 7
Ps, oh yeah, Methane COULD be a good source of reaction mass for a nuke driver,,,
May 9th, 2007 at 11:11 am
uNotice the truck tip forward when the ebgibe fires up? As Pinky would say, “naaaaaaarrrfff!”
May 9th, 2007 at 11:12 am
Oh man, that’s what you get for typing with a 3 year old on your lap! Notice doesn’t start with a u and that’s not how you spell engine!