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This unclassified Defense Intelligence Reference Document from the Defense Intelligence Agency is dated 2 March 2010. It was produced in FY 2009 under the Advanced Aerospace Weapon System Applications (AAWSA) Program. The report reviews work on using positrons as aerospace fuel. It covers air-breathing turbojet and ramjet engines, unmanned aircraft, missiles, single-stage reusable vehicles, positron rockets and a crewed Mars mission, along with how positrons could be produced and stored. It concludes that a first positron-powered flight around the globe could be possible within 10 years.
“Works”9 pages
UNCLASSIFIED/ ;C Antimatter Antimatter appears in the form of fundamental particles that have their sign of electric charge reversed from their matter counterpart. For example, the positron, e+, is the antiparticle to the electron, e-. According to the CPT theorem, 4 properties of matter and their counterpart antimatter particles are identical. This has been tested in the laboratory to an accuracy of roughly 1 part in 10 million. Antimatter is appealing for aerospace uses because its specific energy by annihilation is 180 MJ/μg, or 10 orders of magnitude larger than chemical energy, as shown in Figure 1. I00E<-03 I00E+02 +--------------- I00E+0 I I00E+00 +--------------- I00E-01 Energy Density I 00E-02 +------ MJ/μg I 00E-03 +------ I00E-04 +------ I00E-05 +------- I00E-06 +------ I 00E-07 +------ I00E-08 +-~--~ Chenical Fission Fusion Figure 1. Specific Energy for Chemical, Nuclear, and Antimatter Materials Fbsitron Annihilation In the presence of matter, the positron binds with an electron to form a short-lived atom called positronium (Ps). Depending on the relative spin orientations of the positron and electron, Ps has a mean lifetime in a vacuum of 125 picoseconds (para-Ps, spins antiparallel), or 142 nanoseconds (ortho-Ps, spins parallel). From quantum number conservation, para-Ps decays into two gamma rays of equal energy, 511 kiloelectronvolts (keV), whereas ortho-Ps decays into three gamma rays whose energies add up to 1022 keV. Hence, when Ps self-annihilates, there is 100 percent conversion of mass into electromagnetic energy given by Einstein's famous equation, E = mc2, where c is the speed of light. Although the energies of positron annihilation gamma rays are on the nuclear scale, they have none of the undesirable features associated with nuclear energy. First, the annihilation evolves rapidly (nanoseconds) and is controllable under predictable electromagnetic forces. There is no long-term inertia as with nuclear reactors. Consequently, positron-generated thrust can be throttled. 1 UNCLASSIFIED//EiSi'A. QFFI@Itllt ~:!E! enc I
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 35 pages are in the text index: search them above, or from the library's search.