TRACKING SPACE JUNKSpace is a Busy Place; Directing Traffic is an Important Job
In 1997 Telstar-401 – a communications satellite in geostationary orbit – failed. It now drifts uncontrolled 35,000 km above North America, threatening collision with at least 22 active satellites that provide critical communications capabilities to Canada and the US.
The risk of collision between two objects in orbit around the earth is real. In 1996 a discarded rocket booster impacted the stabilization boom of a French satellite, causing it to tumble uncontrolled until ground controllers were able to upload new stabilization software to the satellite. They were lucky – a few more meters to the side and the satellite would have been destroyed.
It does not take something big to damage a satellite. In a recent incident, a fleck of paint impacted the space shuttle windshield leaving a 4mm crater. The paint chip was probably traveling at about 5 km/sec relative to the shuttle when it struck. The shuttle is built to withstand this sort of impact – many satellites are not. And with the number of satellites and associated debris in earth orbit increasing, the potential for serious collisions is also increasing.
Brad Wallace is a Defence R&D Canada (DRDC) scientist working on Canada's contribution to international surveillance efforts designed to turn space into a safer place. His team is currently deploying a network of three remotely controlled ground telescopes that will monitor some of the earth's larger orbiting objects. The telescopes are to be located across Canada but they will transmit their imagery to Shirleys Bay for data collection and analysis.
"One of our goals" says Dr. Wallace, "is to demonstrate our ability to collect useful data as a starting point from which to begin work with the Americans as a part of their larger surveillance system."
Dr. Wallace explained further, "The U.S. Department of Defence currently operates the Space Surveillance Network (SSN). Their goal is to keep track of all orbiting objects larger than 10-30 cm. Where possible, the SSN attempts to identify the object, and in the case of operating satellites, their capabilities. Current estimates are that there are about 9000 orbiting objects of this size. The Department of National Defence is currently in the process of procuring a space surveillance satellite called Sapphire. This will link with the U.S. Space Surveillance System and significantly enhance Canada’s role as a partner in this critical mission. The work we are doing at DRDC is providing the foundation for the inclusion of both our network and Sapphire into the SSN."
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