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This Defense Intelligence Reference Document, dated 1 November 2010, was produced by the Defense Intelligence Agency under its Advanced Aerospace Weapon System Applications (AAWSA) Program. It surveys propulsion technologies that include chemical, ion, and nuclear fission rockets, fusion schemes, aneutronic fusion, and antimatter propulsion. It also covers radiation shielding and speculates on research needs over the next 30 years for missions from low Earth orbit to Mars, Jupiter, Saturn, and Alpha Centauri. The document concludes that aneutronic fusion promises to be an important mechanism for future space propulsion.
“Anderson”1 page
UNCLASSIFIED//FIHl 8FFI~II k 1!55 0111 Y Chapter 3: Aneutronic Nuclear Fusion Schemes Up to now, the fusion schemes described have the lowest fusion initiation temperatures ranging from 10 million kelvin to about 300 million kelvin. Most of the energy released from the fusion schemes in Figure 7 also release more than 80% of their energy in neutrons. Neutrons are difficult to shield and present a safety concern for the crew of a fusion-powered spacecraft. Unlike charged particles, their energy cannot easily be converted into electricity using magnetohydrodynamic generators and they cannot be focused into a propulsion beam to generate thrust. As a result, aneutronic fusion schemes have been explored for possible use in space propulsion. The schemes with the lowest temperature threshold are highlighted in Figure 9. ,'D + 23He ➔ ,'p [14.7 MeV] + 24He [3.6 MeV] ,'D + 36Li ➔ 2 x 24He [11.2 MeV, each] ''p + 36Lj ➔ 23 He [2.3 MeV] + 24He [1.7 MeV] 23He + 36Lj ➔ ''p + 2 X 24He + 16.9 MeV 23He + 23He ➔ 2 X 11p + 24He + 12.86 MeV ''p + 3?Lj ➔ 2 x 24He [8.6 Mev, each] ''p + s11 B ➔ 3 X 24He + 8.7 MeV ''p + 71sN ➔ 23He + 612c + 5.0 MeV Figure 9. Aneutronic Fusion Schemes Deuterium is readily available by centrifuging water, and protons are ionized hydrogen atoms. Helium-3, however, is very rare on earth, although quantities of it exist in lunar regolith due to ion impact on the Moon from the Sun. Over one million tons of helium-3 is estimated to exist on the lunar surface. Removing the helium-3 schemes does shorten the table, and one of the most attractive schemes uses boron-11. Boron is readily available on earth and 80.1% of naturally-occurring boron is boron-11. A consistent method of comparing each fusion scheme is based on how difficult it is to initiate fusion. In 1955, John D. Lawson established a standardized measurement of the performance of each fusion scheme based on the conditions required to initiate or ignite fusion. Three terms occur in his performance number, referred to as the "Lawson criteria." The triple product includes the plasma density (ne), the energy confinement time (TE), and the plasma temperature. Lower values of the Lawson criteria indicate better fusion ignition performance. The Lawson criteria for D-T fusion is 34; this figure of merit is only 0.43 for the first aneutronic fusion scheme, D-He3. Two of the best performing schemes are p-Li6 at 0.005 and p-B11 at 0.014. The ion temperatures required for both of these schemes UNCLASSIFIED//F811. 8FFl81*1e lal!i! 8111!¥ 18
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 50 pages are in the text index: search them above, or from the library's search.