Riding Anti-Electrons to Mars
A new twist on the nuclear thermal rocket: forget the uranium, use antimatter:
When antimatter meets matter, both annihilate in a flash of energy. This complete conversion to energy is what makes antimatter so powerful. Even the nuclear reactions that power atomic bombs come in a distant second, with only about three percent of their mass converted to energy.Previous antimatter-powered spaceship designs employed antiprotons, which produce high-energy gamma rays when they annihilate. The new design will use positrons, which make gamma rays with about 400 times less energy…
Positrons are directed from the storage unit to the attenuating matrix, where they interact with the material and release heat. Liquid hydrogen (H2) circulates through the attenuating matrix and picks up the heat. The hydrogen then flows to the nozzle exit (bell-shaped area in yellow and blue), where it expands into space, producing thrust.
Not quite as sexy as the science fiction versions (which, it has to be admitted, are typically a bit sketchy on the details), but whatever works.
Such an engine would be safer for the astronauts and for the environment for several reasons: it would reduce the travel time to Mars, increasing safety for the crew by reducing their exposure to cosmic rays; the reactor would not be radioactive after its fuel is used; and there should be no risk for the public even if the reactor exploded during its launch because “gamma rays would be gone in an instant.”
Uh-huh…as would a good chunk of the spaceport. I don’t want to sound like the Atomic Fearmonger here, but I suspect that being “gone in an instant” would be small comfort to the living things that shower of gamma rays passed through along the way.
(And speaking of Bruce, who I haven’t lampooned much lately, how can someone read the accounts of the recent protests in France against reforms to unsustainable employment regulations aimed at reducing youth unemployment and get the story so completely wrong? I guess the facts don’t matter when you see the world through Marx-colored glasses.)
