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This Defense Intelligence Reference Document was prepared by the Defense Intelligence Agency's Defense Warning Office and dated 2 March 2010. It is one of a series of advanced technology reports produced under the Advanced Aerospace Weapon System Applications program. It looks at using positrons as fuel for air-breathing turbojets, ramjet-assisted missiles, single-stage reusable vehicles and rockets for a manned Mars mission, and it also covers positron production, costs and storage. It concludes that a first positron-powered flight around the globe could be possible within 10 years.
From the source:Release of 2026-09-18 Incident: 3/2/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD examines positrons as a possible fuel for advanced aerospace propulsion, arguing that antimatter offers extraordinary energy density and could, in principle, support applications ranging from long-endurance aircraft and missiles to single-stage launch vehicles, onboard power systems, and crewed Mars missions. At the same time, it makes clear that the concept depends on resolving major unsolved problems in producing positrons in sufficient quantities and storing them safely for long periods, and much of the document’s discussion of flight systems and Mars missions remains conceptual rather than closely tied to demonstrated engineering practice. Its overall conclusion is that positron propulsion is theoretically attractive, but remains highly speculative as a practical technology because its core production and storage requirements remain unsolved.
UNCLASSIFIED//FOR OFFl@IAL l!ISl!!! 9Ht5i" components. Alternatively, solar collectors or closed-loop nuclear reactors could be employed . To improve ablation efficiency, annih ilation gamma rays must be wavelength shifted (WLS) by passing them through a high-Z WLS material. The material of choice, lead, also serves as the shell of the Ps pellet. The pell et vaporizes into high-energy plasma, and the WLS photons propagate to the pressure plate. Silicon carbide ablation material has been adopted from the antiproton catalyzed microfission/fusion concept4°, 41 developed at Penn State University by the author and coworkers . Photon energy distribut ions are shifted through 2 cm of lead to 1-10 keV from 511 keV with 85 percent efficiency. Performance depends primarily on the energy of the WLS photons and the energy per pellet. At 8 keV, l sp is in the range 1,200 -3,000 sec. Thrust is 40 - 145 kN, the latter at a pellet injection rate of 1 hertz. The tot al quantity of posit rons consumed for a one-way trip to Mars over th is range of l sp is 15-40 mg with 50 percent of gamma rays striking the plate and a 85 percent WLS efficiency. POSITRON ROCKET SYSTEM COMPARISON A side-by-side comparison of three positron rocket propulsion concepts is presented in Table 5 for a one- way transit to Mars using t:N = 3. 7 km/sec. Table 5. Comparison of Three Positron Propulsion Concepts for Mars Mission Solid-Core Gas-Core Sanger Ablation lsp 650 - 920 sec 1000 - 2500 sec 1200 - 3000 sec Thrust 72 kN , small class 130 kN (1000 aim) 40 -145 kN (1 Hz) Limits • Wa ll and nozzle temperature • Wall and nozzle temperature • H Ionization • Positron density per pellet e+ mass • 6-9 mg (100% efficiency) • < 25 mg (85% efficiency) • 15 - 40 mg (42.5% efficiency) Special • Continuous burn • Pulsed burn • Pulsed burn Notes • Multiple engines may be possible • Hot-bleed line possible • Multiple engines may be possible • Hot-bleed line possible • Engine can be throttled • Multiple engines may be possible • No direct onboard power • Engine can be throttled Future work • Efficiency study • Efficiency study • Lower pressure possible? • Further WLS and radiation transport study UNCLASSIFIED/;'rett 8FFI&IAk Uiili ODIL¥ 17
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Official release, from the pursue 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.