Original URL: http://www.theregister.co.uk/2008/04/10/us_satellite_to_spy_on_spy_sats/

US will sky spy-sat to eye spy-sats

Watch out for the watcher-watcher

By Lewis Page

Posted in Science, 10th April 2008 14:48 GMT

Announcements from the Pentagon have put a price and an initial schedule on a new American military satellite which will be used to keep track of other countries' spy satellites.

According to a report in Aviation Daily & Defence Report, the new Space Based Surveillance System (SBSS) Block 10 spacecraft is slated for launch in early 2009 at a cost of nearly $824m. The new spy platform, rather than looking down at the Earth like most such spacecraft, will carry a telescope designed to let it scan the skies for other secret sats.

Thus far, the US military has had to use ground-based sensors for this task. This means that satellites in high geostationary orbit have been difficult to keep an eye on, because they can only be seen during a clear, cloudless night for the ground sensor. Also, sunlight needs to be reflecting from the sat under observation.

Furthermore, even lower-orbiting spacecraft are relatively difficult for ground scopes to keep track of as they tend to be below the horizon much of the time. Spy satellites are designed with a relatively large ability to change their orbits. Thus, sneaky foreign snoopers can carry out a manoeuvring burn while hidden on the other side of the planet from US watchers, and when they come round again they will be in an unexpected place and time.

"You might recognise that there was a satellite here and now the satellite is not there, but it takes me a while to go and find it," according to Colonel Shawn Barnes of the US Air Force Space Command.

"With SBSS, we are going to have a good ability to be able to track those changes," Barnes told AD & DR.

In addition to the watcher-sat-watching sats, the SBSS programme will also seek to tie in data from a variety of other sources, including ground and seagoing radars operated by America and allied countries.

SBSS follows pleasing results from the Space Based Visible (SBV) sensor, which was orbited in the late 1990s aboard a missile-defence test spacecraft and worked much better than expected. The initial Block 10 pathfinder SBSS platform - originally scheduled for later this year - will be followed by snazzier Block 20 kit.

Critics of the programme have said that tracking foreign spacecraft will result in aspirations towards attacking them too, and that SBSS is thus the first step towards a space warfare capability and militarisation of space.

US diplomatic policy is formally against such militarisation, a decision taken during the late Cold War following both US and Soviet anti-satellite weapon tests.

However, the idea is back on the agenda following an anti-sat test shot by China last year and America's successful strike against a duff spy-sat of its own last month.

The US makes no bones about its desire to have weapons which can destroy ballistic-missile warheads outside the atmosphere, and the defective spy platform was hit with one of these. This tends to indicate that the line between a missile-defence system and a space-war capability - at least in the case of lower orbits - is a rather blurred one.

Anyway, at least now we know the answer to the old question regarding who will watch the watchers. ®