Documents / Report
This Defense Intelligence Reference Document was prepared by the Defense Intelligence Agency under its Advanced Aerospace Weapon System Applications (AAWSA) program, is dated 6 April 2010 and is part of a series of advanced technology reports produced in FY 2009. It reviews proposed laboratory generators and detectors of high-frequency gravitational waves for communications. It favors an infrared-excited molecules transmitter and the Li-Baker detector, estimating about 1.9 million bits per second over 7,000 km through the Earth. It also discusses timing standards and interplanetary navigation uses.
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UNCLASSIFIED//F'iA. 'iFFUil,t,I, l!l!ii! 8111!lf 3.4.1 Propagating Signals From Optical Lattice Clocks for Timing The 1 part in 10 18 measurement precision of optical lattice clocks will be affected by general relativity effects, in other words propagation delays due to gravitational field gradients will be readily measureable. "It will make us think a little harder about what we really mean by time," Kleppner (2008). In effect, measuring the propagation delays at this level allows very fine measurement of the "geoids," or surfaces of constant gravity, surrounding planets and inhabiting interplanetary and interstellar space. The delay experienced by RF waves could therefore be precisely compared with the propagation delay experienced by gravitational waves, which are not as strongly affected by the presence of mass. Such a differential propagation delay comparison (between RF & GW) could lead to an important new technology in the mapping of geoids, which could for instance be applied to the problem of mapping the positions of the Lagrangian points, which vary slightly over time. 3.4.2 In Navigating and Mapping Interplanetary Geoids The importance of locating and navigating to Lagrangian points is well established (Baker, 1967). See Figure 23 for a depiction of the Earth's Lagrangian points and their uses. Gravity holes The Earth and 5un'5 gravitational field5 balance at five Lagrangian point5, Ll to LS. Later this year the~ TEREO A and B 5pacecraft will explore the L4 and L5 region5 for the fir5t time L3: I IIT•IY 1,nsi -,r1~ :,__ ,, '.L •~· ,;·, 1,1' ···,,11 p., 1c;t nt1C"· ~1an~ts r_~AVl~A.T CNA_ ~ ELJ CO\. TC Uk} • c•,r-- f ,:,r • 1·1 l~"'.01 c,r ,lt o-, • • ri ·1,'.r;ri:1q 111cc ·-,_,. °"'--""" •:, I\A',A' Ai 1.: '--'."Vi~1-,1 ','/I~.,:. q\p •ps L5:',tdl.•I~ 1~.;y;r,· I~ ·1 ,11 i, '. en~ r,0'.'Ml\;• >J'.e'I t~ -nee r·1JrlL< ,~1~11110. • 1e,;r~e1 sir,] _,7r,p:; \•',' 0 ~~, CJ¥." t~ ~•.c,~;e_ •.v·II _•11 •.: ·-,~-c• Figure 23. The Earth's Associated Lagrangian Points [New Scientist, 9Feb09 and Baker (1967), p.128, Figure 2.2] 31 UNCLASSIFIED/ ,'f81il BrrIeI111t ""I! OICL I
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 57 pages are in the text index: search them above, or from the library's search.