I hadn't heard about the metastable helium before. Have to look into that one.
There are several other nitrogen allotropes of interest besides N20. N12 is one, and I think it and N20 my have been created in tiny amounts. N60 is another. Only theoretical, but...
Antimatter rockets have a couple of *real* problems and one interesting advantage.
Positron-electron reactions generate gamma rays. Which are hard to direct. That spreads out the exhaust a fair bit.
Worse, proto-anti-proton reactions generate gamma rays and pions. The pions live long enough to treat several kilometers before decaying.
The advantage is that apparently the ideal mass ratio for an antimatter rocket is 4. But you can vary that for being equal amounts of matter/antimatter to being a lot of matter and a "tiny" bit of antimatter. The more antimatter the better the Isp. Until you hit 50-50.
(The above comes from info in Dr. Forward's Indistinguishable from Magic)
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timeasmymeasure
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Date: 2020-10-09 05:06 pm (UTC)There are several other nitrogen allotropes of interest besides N20. N12 is one, and I think it and N20 my have been created in tiny amounts. N60 is another. Only theoretical, but...
Antimatter rockets have a couple of *real* problems and one interesting advantage.
Positron-electron reactions generate gamma rays. Which are hard to direct. That spreads out the exhaust a fair bit.
Worse, proto-anti-proton reactions generate gamma rays and pions. The pions live long enough to treat several kilometers before decaying.
The advantage is that apparently the ideal mass ratio for an antimatter rocket is 4. But you can vary that for being equal amounts of matter/antimatter to being a lot of matter and a "tiny" bit of antimatter. The more antimatter the better the Isp. Until you hit 50-50.
(The above comes from info in Dr. Forward's Indistinguishable from Magic)