AST & Science, a Texas-based company, has applied for approval to build SpaceMobile, which claims to be the “first and only space-based cellular broadband network to be accessible by standard smartphones.” Its proposed network is under review by the FCC. However, NASA reckons it will heighten the risk of contact between spacecraft within a region that is already crowded.
The space agency is particularly concerned about the gap between 690 and 740km above Earth, an area home to the so-called A-train. The A-train consists of ten spacecraft used to monitor Earth, operated by various groups including NASA, the United States Geological Survey, France’s National Centre for Space Studies, and Japan’s Aerospace Exploration Agency. AST wants to place its satellites across 16 orbital planes at an altitude of 700km, a distance that’s too close for comfort.
“The AST constellation would be essentially collocated with the A-Train if the proposed orbit altitude is chosen,” Samantha Fonder, NASA’s Representative to the Commercial Space Transportation Interagency Group, and a member of its Human Exploration and Operations Mission Directorate, wrote in a letter [PDF] addressed to the FCC.
What’s more the area is also particularly risky since it contains chunks of debris leftover from a previous orbital crash. “Additionally, this is an orbit regime that has a large debris object density (resulting from the Fengyun1-C ASAT test and the Iridium33-COSMOS 2251collision) and therefore experiences frequent conjunctions with debris objects,” she continued.
Fonder reckons that placing another 243 satellites near the A-train will increase the chances of a space smash. NASA has arrived at that conclusion by taking into account various factors, including the size of the AST’s SpaceMobile birds. They are much bigger than the spacecraft in the A-train and carry 900-square-metre antennas.
Robin Edgar
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