ESA builds air-breathing engine that works in space The European Space Agency has hailed the successful test of an air-breathing engine that works in space. The engines don’t need the oxygen found in air to burn. Instead, as the ESA has explained here, the idea is to collect air, compress it, give it a charge and then squirt it out to provide thrust. The engine has no moving …
I was thinking more of how they could move from being proof of concepts and a way to get students interested in space to a workhorse platform that can do interesting or helpful stuff faster, cheaper and easier than higher orbit sats but I should have figured out el reg regulars would find a way to view it from another angle.
"[...] I should have figured out el reg regulars would find a way to view it from another angle."
Think of it as a game of political correctness or chess. You think twice about what you have done to see if you have left anyone room to manoeuvre**. Then you decide if you want to be amused by the exploits - or you hope someone will make a move for which you have a counter already prepared.
Lateral thinking is an ability to be prized in IT. Bangor University Electronic Engineering department ran degree applicants through a few tests - and that was a sought after trait. A question I remember was simply "what is a U2". To which there were several answers at that time.***
**correct spelling - unlike the lorry warning sign that Waitrose put outside some store delivery bays.
***battery (now D type); submarine, spy plane. The pop group didn't come along until later.
"the engine is slowing it down"
OK - I do a mini-simulation in my head, and I see air going into some kind of 'scoop' device, like what you might see on a ramjet [only a "space" version], and I consider a few things that aerodynamics might cause some trouble with:
a) when the air enters the scoop, how does it get collected exactly? [you need some kind of compressor pump I'd think]
b) while air is collecting for a compressor pump intake cycle, wouldn't it build up enough pressure to exert an impulse on the satellite, causing it to slow down just a bit more?
c) is the electrostatic acceleration going to be ENOUGH more than the (effective) drag caused by the intake scoop going to be enough to overcome the additional drag of the satellite itself against the atmosphere? [this includes the solar panels, too, which just might not be all that streamlined]
I imagine the rocket scientists have thought all this out. Hopefully I didn't just poop their party.
Nice to finally see electrokinetic (or "ion wind") effects finally being exploited in space. As a former participant in BAE's Project Greenglow I was aware of attempts to interest Surrey Satellite Technology in this idea more than 15 years ago.
https://en.wikipedia.org/wiki/Biefeld%E2%80%93Brown_effect
https://en.wikipedia.org/wiki/Electrohydrodynamics
https://en.wikipedia.org/wiki/Ionocraft
Conventional jet engines have heavy-duty compressor turbines at the front, although when flying at speed, the compressor is mostly just compressing further an already compressed stream. (Compressed by intake geometry, that is.) This thing is more like a ramjet, in that it has no turbines to compress the incoming flow, and relies entirely on the intake geometry to do so.
Note: that's why ramjets don't work at airspeeds below about Mach 0.5, of course. They rely on the air being, well, rammed in by the airspeed.
Yes that would pretty much describe it.
The trouble with this tech is
a) Who has sats that need to keep station around this height
b) Who can afford the development budget for them.
Historically I think most of the people in a) don't have the money for b).
Hence the 60 year delay in getting it into a lab test.
"didn't I have the ability to fuel harvest in Elite?"
Not the same thing. Elite just allowed you to harvest fuel and store it until you needed it. This idea is instead a kind of ramjet, where the fuel is scooped straight into the engine and used immediately. It's still not a new idea, since ramjets have been around for a while, but this is the first time the principle has been applied to an ion engine rather than an actual jet.
Also wouldn't the drag in even a depleted atmosphere negate the acceleration from the ionized air?
That would depend primarily on how much energy you have available to ionise and accelerate the collected air. I expect they've done the calculations, what with them being, you know, fucking rocket scientists.
A turbomolecular vacuum pump uses a high speed turbine to sweep gas molecules towards the high pressure side. They operate around the 1 x 10-8 atm level and the thrust would be equivalent to how much more 'push' (increase in velocity) you could give the molecule
Ionization gives much higher velocities to the gas, and since thrust is mass x velocity, more effective.
"Would't the spacecraft need moving parts to suck in the air in the depleted atmosphere?"
Depends on which way the wind is blowing and how fast. Orbital velocity is a tad higher than even a Tesla in Ludicrous mode. The ISS is travelling at about 17,150mph and the lower the orbit, the higher the velocity.
We need you to build a vacuum chamber for us.
"Okay..."
Big enough to put a satellite in.
"Okay"
And then, and you're going to love this, we need you to turn it into a wind tunnel.
"Oka- what?"
We need you to make it a really powerful wind tunnel too. One to simulate 7.8km/s."
"Back up. A wind tunnel in a vacuum?"
Yeah. Well, that's okay because we both know you engineers can't make a pure vacuum. We need space levels of vacuum. And we need it to move really fast.
"Hey! We can make a vacuum! But you want your vacuum to move really fast? There's nothing there to move."
We know. That's why you'll need a really big fan. That nothing has to do 7.8km/s. Then we're going to compress it, ionise it, and see if it goes forwards.
"You want to compress high speed nothing, fiddle with it, and see if it will give you forward thrust into a 7.8km/s headwind of nothing?"
Yep.
It's at this point half the engineers quit to go become landscape gardeners and the other half get a slightly crazed look in their eyes and start muttering into their beards.
"It's at this point half the engineers quit to go become landscape gardeners and the other half get a slightly crazed look in their eyes and start muttering into their beards."
Nicely done. I "heard" that in the voice of Bob Newhart. Have a pint on me.
>Remember the "faster than light particles", a.k.a. Loose GPS cable? Mistakes happen.
And Fleischmann–Pons cold fusion reactor, it was subsequently found to be the effect of one of the experimenters hard boiled lunch eggs had dropped into the chamber which promptly went critical on removal.
Nuclear fusion reactions are easy to produce. The Farnsworth Fusor is one example.
The hard part is getting more energy out of the building than went into the building.
They've only just managed to break even on energy in vs generated in the chamber after 40+ years of trying, let alone getting a profit on energy out of the chamber. As any electrical engineer will tell you, until you get over unity on the entire site you don't have a viable power source.
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