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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.
“Mission Control”1 page
UNCLASSIFIED//F811. 8FFll!l*L 1!1!11! t!IIU:!Y THE GAS-CORE POSITRON ROCKET The gas-core positron concept follows nuclear gas-core concepts, 31 , 32 , 33 which are different from the solid-core concept in that gamma rays directly heat a fluid under pressure. The limit of the solid-core approach is melting temperatures of the solid matrix gamma ray attenuator. By direct heating, temperatures can increase significantly as long as the gas does not appreciably heat the walls. Four versions of the gas-core concept are illustrated in Figure 12. Synchronous with pulsed Ps injection are (a-c) pulses of LN2 or LNe or LH 2 with LXe gamma ray attenuator and (d) pulses of LH2 where Psis encapsulated in lead, a gamma ray converter. For fluid injection, a turbo-pump (not shown) is located upstream, with power obtained from a positron Brayton cycle system described later in this paper. Results from computational fluid dynamics codes reveal that high-density regions of the fluid move away from the gamma ray source when the power in the system exceeds 300 megawatts. Under these conditions, the propellant does not efficiently absorb gamma rays. Furthermore, calculations of heat required for continuous operation suggest the vortex configuration of (b) breaks down and reverts to two-fluid flow. However, both the two-fluid, flow-through model and the Ps lead-cartridge concepts show promise if the mass flow rate of the hydrogen propellant exceeds that of the xenon or lead by a factor of five. By operating in a pulsed mode, one should be able to control the positron delivery into the chamber core. With complete absorption of gamma rays in the 2-cm lead casing, performance of the system matches that of previously examined systems. 34 , 35 Thrusts of 130 kN (1,000 atmospheres) are predicted for a single-engine system with an efficiency of 85 percent. Burn times are 30 minutes for t:N = 3.7 km/second (sec) with 25 mg of positrons consumed for a 50,000-kg burnout mass. The limit of the gas- core concept occurs near the thresholds for ionization of hydrogen, corresponding to Isp of~ 2,500 sec. 14 UNCLASSIFIED/ }liiOAt Oliiliil&l11J.k W&Eii SU.kif
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 35 pages are in the text index: search them above, or from the library's search.