[FPSPACE] FW: Centauri Dreams - Antimatter For Deep Space Propulsion

[LARRY KLAES]

>From: Centauri Dreams <gilster at mindspring.com>
>Reply-To: Centauri Dreams <gilster at mindspring.com>
>To: ljk4 at msn.com
>Subject: Centauri Dreams
>Date: Mon, 5 Nov 2007 14:08:35 -0600 (CST)
>
>Centauri Dreams
>
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>Antimatter For Deep Space Propulsion
>
>Posted: 05 Nov 2007 08:14 AM CST

>http://www.centauri-dreams.org/?p=1564
>
>
>Great ideas fan out in unexpected directions, which is why James Bickford 
>now looks at antimatter in a new light. Bickford (Draper Laboratory, 
>Cambridge MA) realized that an adaptation of Robert Bussards interstellar 
>ramscoop might have its uses in collecting antimatter. The concept grew out 
>of the realization that antimatter sources were available not only near the 
>Earth but farther out in the Solar System, where antiparticles could be 
>collected and used to boost spacecraft initially to speeds of 100 
>kilometers per second. Thats sufficient for interstellar precursor missions 
>outside the heliosphere, including the possibility of getting a payload to 
>the Suns gravitational focus, where a new kind of space-based astronomy 
>waits to be exploited.
>
>Refine the process enough and you start talking about even greater speeds 
>through more efficient antimatter collection, one great benefit being that 
>instead of producing the stuff in Earth-bound particle accelerators, youre 
>actually mining natural supplies. Bickford was kind enough to pass along 
>his complete final report for NASAs Institute for Advanced Concepts (NIAC), 
>one of the last projects funded by that agency as it encountered the kind 
>of budgetary crises familiar to deep space researchers and closed. Its a 
>fascinating document that I want to discuss over several days this week 
>(though perhaps not consecutively, because were about to get some 
>interesting exoplanet news).
>
>Before we get into collecting it, ponder the beauties of antimatter itself. 
>The annihilation of a particle with its antiparticle liberates the entire 
>rest mass of each as energy. Indeed, the process is so spectacular  ten 
>orders of magnitude greater than chemical reactions, and between 102 to 103 
>more efficient than nuclear  that antiprotons on the order of tens of 
>nanograms might be sufficient to reach the 100 km/sec velocities mentioned 
>above. Clearly, larger quantities of antimatter expand the options 
>enormously, offering higher speeds still up to the relativistic velocities 
>needed for interstellar missions.
>
>Bickfords numbers on antimatters potential further drive the point home. 
>The annihilation of a single kilogram of antimatter releases the energy 
>equivalent of thirty million barrels of oil. If you work out worldwide 
>energy production per year in these terms, you find that the total is 
>equivalent to 2200 kg of antimatter. Contrasting sharply with antimatters 
>potential, however, is the price. Using the methods available today, which 
>rely on extracting antimatter from sub-atomic collision debris in 
>accelerators, the worldwide output is in the low nanogram per year range. 
>The cost: an estimated $100 trillion per gram, give or take a few 
>megabucks.
>
>Thats one reason that antimatter propulsion concepts have taken a sharp 
>turn toward the realistic after heady earlier speculations. Antimatter 
>Catalyzed Microfission/Fusion, which uses antiprotons to trigger a 
>efficient form of nuclear fission, has been extensively studied at 
>Pennsylvania State University, showing potential for interplanetary 
>missions (Mars becomes reachable in about 45 days). And ACMF is, as it has 
>to be, stingy with the antimatter, requiring only nanogram quantities. 
>Steven Howe examined a variant of this approach in an earlier NIAC study, 
>while Gerald Jackson produced a NIAC study on harvesting antimatter that 
>would factor into Bickfords later analysis.
>
>Can we think about getting antimatter up to the microgram level? With ten 
>micrograms of antiprotons, we can envision a 100-ton payload on a one-year 
>round-trip mission to Jupiter. But how do we go about producing antimatter 
>at this level, and where is the best place to produce it? In my next post 
>on Bickfords work, I want to contrast current production methods with the 
>antimatter harvesting option and explain why our own Solar System may serve 
>as a renewable source of the fuel we need once we can build the 
>infrastructure necessary to collect and deploy it. Well talk about these 
>and other issues soon, and also discuss what techologies will have to reach 
>an appropriate readiness level before we can put an efficient antimatter 
>collector into operation.
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