How green is your ROCKET FUEL? NASA is plotting the end of the hydrazine era, and has announced some successful tests of “green” propellants to replace it. Hydrazine, which has burned beneath bloody big rockets since World War Two, produces decent thrust, but it's toxic and difficult to handle. So, as the space-boffins explain here, a “green” alternative …
"Swedish chemical company Eurenco Bofors" - I wonder if they're related to the WW2 Bofors. Their claim to fame was to build excellent guns and sell to both the Allies and the Nazis.
If they are the same company, will they be flogging their rocket juice to the Russian, Chinese and Indian space boffins as well?
"...near perfect green fuel..."
Ah, no, not really. Yes, hydrogen burned with oxygen gives us clean, green water vapour, yes but...
Making hydrogen for fuel is, sadly, a very ungreen process, with lots of CO2 released into the atmosphere during the manufacturing stage.
And a smaller issue is, if someone spills kerosene all over you, you just need to a: change your clothes and have a shower (quickly!) and b: stay away from sparks, fires and whatnot. If someone spills (spill, as in, pour a liquid) hydrogen over you, it's fair to say that they've ruined your whole day.
So it's a fuel that's green to make as well as use...
"If someone spills (spill, as in, pour a liquid) hydrogen over you, it's fair to say that they've ruined your whole day."
I have absolutely no idea why would you make such a ridiculous claim?!? Granted, hydrogen would be a bit colder but at that point I just don't think it would fundamentally change the outcome...
"NASA already has a near perfect green fuel for big rockets: Hydrogen and Oxygen"
Agreed, a Hydrogen / Oxygen mixture makes an excellent propellant for getting a vehicle to orbit, as it ignites easily at launch, and once burning it stays lit (the Space Shuttle only experienced one major main engine failure in the entire programme, and that was a deliberate engine shutdown due to multiple sensor failures - even then the Shuttle still managed to abort to orbit, albeit a lower one than planned.)
However, once in orbit with very little atmosphere and extremes of temperature, ignition of a Hydrogen / Oxygen mix becomes less reliable, so hypergolic fuels such as hydrazine derivatives are often used as they spontaneously ignite when mixed with nitrogen tetroxide i.e. no ignition mechanism required. This is particularly useful when short bursts of propulsion are required for small manoeuvres i.e. the thrusters they are talking about in this article. The Shuttle also used Hydrazine derivatives in its two Orbital Maneuvering System engines for orbital insertion and de-orbit burns.
yes but these thrusters are just used for rotating the satellite and, I suspect (although I'm no rocket scientist) that, the 22N ones are for minor orbital changes. Basically these are just for pootling around (*) not for major course adjustments.
(*) - I think the technical term is "station keeping"
That's an understatment.
$orkplace has an instrument off the first Ariane 5 launch (the one which famously, didn't) that was dug up from 8 feet down in a french Guyanian swamp and then thoroughly cleaned to get rid of the mud. It got returned to assess how well built it was.
It's in a glass case because 20 years later it _still_ has enough trace hydrazine on it to be dangerous if touched.
Hydrazine is a fluffy kitten compared to some of the things used as propellants.
A wee dram of red fuming nitric acid anyone? No? How about a gulp of liquid fluorine?
And then we get to the things that have been proposed as fuels, although no-one has been daft/brave enough to use. Fun things like the violently hypergolic chlorine tri-floride.
(Bonus video of ClF3 setting fire to, well, everything.)
The Museum of Berkshire Aviation just south east of Reading is well worth a visit. It's a fairly small place but has so much oddball stuff and the exhibits are more accessible than most of the mainstream museum.
It has a large part of a Chevaline ( our advanced version of the Polaris ) on display. From memory it is the Penetration Aids Carrier, the "top part" of the missile which is in space and drops off the warheads. You can see the quality of construction, it is quite stunning.
(sorry for the non scientific descriptions..... Just get along to visit & support)
Edited to add this link. I'm not affiliated, it's just a great place.
http://www.globalaviationresource.com/reports/2011/moba.php
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