from the check-out-glasses-guy-in-the-header-image dept.
According to a press release from the European Space Agency (ESA), a team of scientists from Airbus have succesfully tested a prototype 10 N hydrazine thruster, its chamber and nozzle made out of a platinum–rhodium alloy, printed with "a laser machine normally employed for making jewellery, which is the current industrial state-of-the-art for manufacturing with these metals"
The world's first spacecraft thruster with a platinum combustion chamber and nozzle made by 3D printing has passed its baptism of fire with a series of firings lasting more than an hour and 618 ignitions.
"This is a world first," explains Steffen Beyer of Airbus Defence & Space, managing the project. "The firings included a single burn of 32 minutes, during which a maximum throat temperature of 1253°C was attained.
The main reason for 3D-printing was economical:
"Considering that platinum currently costs €40 a gram [sudo rm -rf: it seems to be more like 30€], 3D printing offers considerable future savings," added Dr Beyer. "We produce 150–200 thrusters in this class per year for different customers. 3D printing should allow shorter production cycles and a more flexible production flow, such as manufacturing on demand."
Original Submission
(Score: 2) by sudo rm -rf on Saturday June 20 2015, @04:59PM
from the check-out-glasses-guy-in-the-header-image dept.
He seems to enjoy himself quite a bit. I always wondered if I should apply for a job at ESA, now I'm a 100% positive!
(Score: 3, Interesting) by MichaelDavidCrawford on Saturday June 20 2015, @05:28PM
I have often wondered why they haven't come up with anything better.
The reason hydrazine is used is that it bursts into flame when mixed with fuming nitric acid. You don't need an igniter so the thruster is smaller, lighter and more reliable. Consider what a drag it would have been for the Apollo astronauts were their guidance thrusters to flake out as they prepared for reentry.
In the other hand, hydrazine is profoundly toxic, while leaving a bottle of fuming nitric acid open in a room will eventually lead you to cough out bloody chunks of your lungs.
I possessed a bottle of fuming nitric acid, as one uses it to clean telescope mirrors prior to silvering them in a chemical bath. When I opened the cap this heavy, thick brown smoke wafted out. That's nitric oxide and is one of the very most harmful components of smog.
If you'd like to purchase you're own bottle, ask at the chemistry stockroom of any University. It will be hand-delivered by the FBI as it is a precursor for many high explosives.
Yes I Have No Bananas. [gofundme.com]
(Score: 4, Interesting) by gman003 on Saturday June 20 2015, @06:26PM
Hydrazine is also used in thrusters like this as a monopropellant. N2H4 => N2 + 2 H2 or 3 N2H4 => 4 NH3 + N2, both reactions are exothermic. And since a) it's only a 10N thruster (about 2 pounds force, for you non-metricated Americans), and b) hydrazine decomposition is catalyzed by, among other things, iridium, it definitely seems this is just an attitude control thruster, not a main engine.
As for why they haven't found anything better yet, there's a bunch of reasons. First, they have found a slightly better one for most uses: dimethylhydrazine is more stable, dense and efficient, and remains hypergolic with RFNA. It doesn't work as nicely as a monopropellant, though, so regular hydrazine is still used for that. Second, hypergolic fuels are hard to develop - scientists spent decades coming up with the UDMH+RFNA combination, and almost as long trying to make it safe. Third, hypergolic fuels are a niche use case, and were mainly developed for military uses, not space. Now that the military's moved on to solid rockets, there's little interest in them. The civilian money is either on cheap stage-one fuels (solids or RP1+LOX), hyper-efficient rockets (LH2+LOX, LH2+LF2, air-breathing rockets, or non-chemical rockets), or space-sourced fuels (liquid methane+oxygen).
(Score: 2) by kaszz on Saturday June 20 2015, @06:47PM
So Hydrazine + Iridium => exothermic reaction?
What's LF2?
(Score: 2) by gman003 on Saturday June 20 2015, @07:48PM
Liquid elemental fluorine.
At least in theory, the most efficient (highest specific impulse) chemical rocket you can make burns F2+H2=> 2 HF, with excess hydrogen. There's honestly not too much research into this anymore, it's too dangerous (as evidenced by the fact that the exhaust compound is pure hydrofluoric acid) and by the time you need that much efficiency, non-chemical rockets are better anyways. But related systems are investigated - fluorine compounds like ClF5 are perpetually on the verge of being used, or so the labs claim.
And pure hydrazine honestly doesn't need much of an excuse to start an exothermic reaction. Iridium is just useful as a way to start a controlled burn, instead of "whoops the whole thing exploded again".
(Score: 2) by fritsd on Saturday June 20 2015, @08:25PM
Can they actually find researchers masochistic enough to want to work with liquid F2??!?
I mean: pp mentioned fuming nitric acid, I once almost mutilated my hand with that stuff (not exactly, it was for nitration, so it was blended with fuming sulphuric acid).
As my glove was beginning to smoke and turn black, I quickly turned the tap on and diluted it. (Remember kids: always wear your rubber gloves in the laboratory).
I don't think anything can protect you if you come in contact with liquid F2. It seems a bit of a prestige project: "MY rocket uses a fuel that other rocket scientists and emergency services don't even dare to come near!!".
And besides, what does the release of several tonnes of HF launched in the air do to the ozone layer?
(Score: 2) by kaszz on Saturday June 20 2015, @09:11PM
Use a robotic hand?
The risk that is harder to avoid is the one any astronaut takes by riding on top of all that explosive stuff. Even if RP1+LOX isn't as bad as hydrazine. I don't it's a good idea to be soaked in it.
(Score: 3, Interesting) by gman003 on Saturday June 20 2015, @10:03PM
Oh, there's people who would work with LF2, and worse.
If you want a nice book to read on the topic, I suggest John Clark's "Ignition!".
He was a rocket chemist, figuring out fuels and oxidizers in the 50s and 60s. He was one of the guys who figured out adding a pinch of hydrofluoric acid to red fuming nitric acid would prevent it from corroding aluminum or stainless steel.
At one point, he was tasked with finding an extremely dense fuel, for use on missiles. Someone suggested to him dimethyl mercury as an additive. He actually tried running tests on it, but when he was unable to find anyone who would synthesize 100lbs of dimethyl mercury, he decided the whole idea was rather stupid (it would merely double density at best, while completely trashing all other performance figures and being unbelievably toxic). To demonstrate this absurdity, he wrote a proposal for an engine that injected straight mercury into the chamber. The theoretical math showed quite a nice improvement in impulse per volume by doing this, but he expected such a ludicrous proposal to be shot down instantly.
Instead, the Navy told him to get to work testing it.
Well, he at least managed to fob the job off on a different test lab, one located in the middle of the desert rather than New Jersey, but they did indeed fire a rocket using liquid mercury as an additive, spraying mercury vapor straight into the atmosphere.
Rocket scientists don't give a shit.
(Score: 4, Insightful) by Ethanol-fueled on Saturday June 20 2015, @06:27PM
The FBI will advertise It to you, deliver it to you, tell you what place you should attack with it, promise you 72 virgins and a lot of money to your family, then arrest you (If not summarily execute you on the spot) and tell everybody America still needs to be afraid because there are terrorists on the loose.
(Score: 2) by takyon on Saturday June 20 2015, @06:58PM
When I point this out, other commenters on other news sites seem to think this is a good thing.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2, Interesting) by JeffPaetkau on Saturday June 20 2015, @10:27PM
I have often wondered why they haven't come up with anything better?
If you want an extensive answer to that question I suggest reading Ignition by John D. Clark which is a very interesting history of the development of liquid rocket fuels.
http://web.gccaz.edu/~wkehowsk/ignition.pdf [gccaz.edu]