Chuck Bednar for redOrbit.com Your Universe Online <\/p>\n
Cryptography, the practice and study of techniques for secure communication in the presence of third parties, could help prevent collisions among the thousands of commercial and spy satellites currently in orbit around the Earth. It would also maintain privacy, according to experts. <\/p>\n
In an article written last month for Scientific American, Brett Hemenway, a research assistant professor with the University of Pennsylvania who focuses on cryptography, and William Welser IV, a space policy expert, explain how it can help avoid potential satellite collisions. <\/p>\n
One such collision took place in February 2009, the authors explained, when the US Iridium 33 satellite and the Russian Cosmos 2251 collided and were both destroyed. Telescopes tracking the two probes from the ground indicated that they should have missed one another, but data from instruments on board either of them would have revealed that they were on a collision course. <\/p>\n
That information was not used, however, because it was deemed to be top-secret. <\/p>\n
Satellite owners view the locations and trajectories of their on-orbit assets as private, Welser and Hemenway wrote. Companies fear that sharing the exact positions of their satellites could help the competition determine the full extent of their capabilities, while governments are afraid that revealing such information could compromise their national security, they explained. <\/p>\n
Yet even minor collisions could cause millions of dollars worth of damage. Debris can be knocked into the path of other satellites, spacecraft carrying a human crew, or even the International Space Station (ISS), the authors wrote. The 2009 incident served as a warning to officials to find a way to fix the problem, but without revealing too much information. <\/p>\n
Adding a third party <\/p>\n
In the current working solution, the worlds four largest satellite communications providers have teamed up with a trusted third party: Analytical Graphics. The company aggregates their orbital data and alerts participants when satellites are at risk, wrote Hemenway and Welser, adding that the arrangement requires that all participants maintain mutual trust of the third party. <\/p>\n
Analytical Graphics, also known as AGI, makes commercial modeling and analysis software for the aerospace, defense, and intelligence communities. The company was founded in 1989 and is headquartered in Exton, Pennsylvania, though it also has offices located in Colorado, California, Washington DC, the UK, and Singapore. Its current CEO is Paul Graziani. <\/p>\n
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