[FPSPACE] 'Antimatter harvester' may fuel future spacecraft
ljk4 at msn.com
Fri Jun 17 15:32:00 EDT 2005
'Antimatter harvester' may fuel future spacecraft
17:16 17 June 2005
NewScientist.com news service
Giant wire spheres may one day float near Earth, scooping up bits of
antimatter for humans to use as space fuel.
The far-fetched idea is one of 12 recently selected to each receive up to
$75,000 from the NASA Institute for Advanced Concepts. The institute
promotes radical schemes that would not necessarily yield results within a
Antimatter particles share the same mass as their normal-matter counterparts
but bear the opposite charge. And while both types of matter are thought to
have been created in equal amounts in the big bang, today there is much more
matter than antimatter in the universe. That is fortunate, since the two
types of particles annihilate each other when they collide, producing light.
But antimatter has been produced in limited quantities in labs, and it forms
naturally in the solar system when charged particles from space, called
cosmic rays, slam into charged particles which stream from the Sun. Several
of the funded proposals aim to collect this nearby antimatter so it could
later be mixed with matter to propel spacecraft out of the solar system by
utilising a solar sail.
In one plan, the antimatter would be collected using three concentric wire
spheres. The outermost, spanning 16 kilometres, would be positively charged
to repel protons from the solar wind and attract negatively charged
anti-protons from space.
These anti-protons would then slow down passing through the middle sphere
and come to rest inside the smallest sphere, which would measure 100 metres
in diameter. An electromagnetic field would trap the exotic particles there.
"Basically, what you want to do is generate a net, just like you're
fishing," says Gerald Jackson, the project's principal investigator at Hbar
Technologies in West Chicago, Illinois, US.
The stored antimatter could then be aimed at a solar sail on a spacecraft.
Controlled reactions with the sail's normal matter could push the craft to
Pluto with just 30 milligrams of antimatter. While a little more - 17 grams
- would take the craft to Alpha Centauri, the nearest star to the Sun,
And he believes there is plenty of antimatter around to fuel those trips.
About 80 grams of the stuff in total may float between the orbits of Venus
and Mars, while as much as 20 kilograms could be harvested within Saturn's
"There's a lot to go after," Jackson told New Scientist. "It's just a matter
of finding an efficient way to do it."
Some of the other concepts selected for further study include a food
"replicator", such as the one made famous in Star Trek, which could create a
variety of meals from just a very few ingredients, and a cable system that
could inflate to make a colossal space telescope.
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