Response to ‘Space, China's Tactical Frontier’ by Eric Hagt and Matthew Durnin

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Notes

¹Eric Hagt and Matthew Durnin, ‘Space, China's Tactical Frontier’, Journal of Strategic Studies 34/5 (Oct. 2011), 733–761.

²NASA, ‘National Space Science Data Center: Haiyang-2a,' <http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=2011-043A>.

³See, for example, SSMIS, http://en.wikipedia.org/wiki/SSMIS> and Microwave Sensors, <www.aerospaceweather.com/dmsp/microsensors.html>.

⁴<http://news.sina.com.cn/c/p/2009-12-15/111819263803.shtml>.

⁵I pointed this out to the authors when reviewing an earlier version of their manuscript. Apparently based on this information, in Table 1 they changed Yaogan-10 from EO to SAR and Yaogan-11 (which was built in Beijing by the China Academy of Space Technology (CAST)) from SAR to EO. Yet they continue to list Yaogan-8 as EO. They should provide a reference for why they believe this satellite is EO.

⁶Global Cloud Cover Maps, <http://home.cc.umanitoba.ca/∼jander/clouds/globalclouds.html>.

⁷SAR sensors can see through clouds, so it would not affect the calculation for those satellites.

⁸NASA, ‘China Launch YaoGan Weixing-9,’ 5 March 2010, <www.nasaspaceflight.com/2010/03/china-yaogan-weixing-9-increase-in-vehicle-production/>.

⁹China Aerospace Science and Technology Corporation, ‘Long March 4-C’, <www.spacechina.com/english/launch_details.shtml?recno=56804>. See also Li Xiangrong and Wang Tieju, ‘Long March 4 Rocket’, China Aerospace 9 (2008) ( (2008 09 )), <www.space.cetin.net.cn/index.asp?modelname=spacechina%2Fdzqk_nr&recno=43 17>.

¹⁰I. Easton and M. Stokes, ‘China's Electronic Intelligence (ELINT) Satellite Developments’, 23 Feb. 2011, 2, <http://project2049.net/documents/china_electronic_ intelligence_elint_satellite_developments_easton_stokes.pdf>.

¹¹A. Andronov, ‘The US Navy's “White Cloud” Spaceborne ELINT System’, Foreign Military Review 7 (1993), 57–60, Table 2, available in translation at <www.fas.org/spp/military/program/surveill/noss_andronov.htm>.

¹²Even if you continue to believe these satellites may have some SAR or IR capability, their coverage would be much smaller than that shown in Figure 1 for the same reason as for Yaogan-8 above. And if they did carry a small optical or IR sensor, those would have low resolution due to the size limit.

¹³In-plane maneuvers of this kind take much less fuel than out-of-plane maneuvers. Such a maneuver in this case would require a velocity change of less than 200 m/s. See D. Wright et al., The Physics of Space Security (American Academy of Arts and Sciences 2005), Chapter 6, <www.ucsusa.org/nuclear_ weapons_and_global_security/space_weapons/technical_issues/the-physics-of-space- security.html>.

¹⁴C.J. Didier, ‘A Commercial Architecture for Satellite Imagery’, Naval Post Graduate School thesis, Sept. 2006, <www.nps.edu/faculty/olsen/Student_theses/06Sep_Didier. pdf>.

¹⁵For satellites at different altitudes, the coverage time will still essentially scale with ground area since, for example, the angular speed across the sky for satellites at 700 km and 1,200 km altitude only differs by about 10 per cent.