Earth’s orbit is starting to seem crowded, so NASA and SpaceX have signed a joint deal that should see satellites like the Starlink constellation automatically move out of the way of NASA’s hardware. The new policy aims to prevent collisions between rapidly moving objects in space, which could prove costly or even fatal in the future.
This is an increasingly timely challenge, given the rapid deployment of Starlink satellites by SpaceX. The company aims to cover the planet with internet connectivity from a constellation of satellites and has launched several bundles in recent months. The pace of this is only expected to increase once SpaceX’s spacecraft is deemed ready to take over launch duties.
The problem is, the space might be big, but the area around the Earth is getting congested. “The agreement covers conjunction avoidance and launch collision avoidance between NASA spacecraft and the large constellation of SpaceX Starlink satellites,” NASA said today, “as well as related carpooling missions ”.
NASA has the easiest part. The agreement indeed stipulates that it will not maneuver its assets in the event of a forecast of a potential crash, unless SpaceX advises otherwise. Starlink satellites, meanwhile, will move away from any NASA science satellite or other assets. This process will be undertaken independently or manually.
Each Starlink satellite is equipped with a global navigation satellite service receiver, which follows its orbit. They can use ion propulsion systems to maneuver independently.
Currently, NASA is evaluating trajectory data from both the space surveillance network that tracks orbiting objects and a logging service operated by the U.S. Air Force’s 18th Space Control Squadron, known as the 18 SPCS). The space agency waits about a week in advance, to map the potential proximity approaches that could take place and develop a mitigation plan.
This may involve possible risks of collision with the International Space Station (ISS) and any spacecraft carrying human personnel, as well as any non-human space flight mission.
“NASA will operate on the basis that the autonomous maneuvering capability of the Starlink satellites will attempt to maneuver to avoid conjunction with NASA assets, and that NASA will maintain its intended course, unless otherwise specified by SpaceX,” said the ‘agreement. “There may be instances, such as a launch anomaly or other anomalies of the Starlink guidance, navigation and control or propulsion system in orbit, where Starlink satellites maneuvering around NASA assets may not be able to operate. not be a feasible option and NASA assets should maneuver.
Part of the deal calls for SpaceX to agree to select Starlink launch injection orbits at least 3.11 miles (5 km) above or below the ISS apogee or perigee. If this is not possible, NASA should expect to be notified within a week of the altitude selection.
Meanwhile, the deal also appears to explore ways in which SpaceX could respond to one of the lingering criticisms of the Starlink system: how visible the satellites are from the ground. The glow of light reflecting off the constellation has led to widespread concern among amateur and professional astronomers, leading the private space exploration company to research methods to make them less reflective.
The agreement with NASA includes a commitment to “share technical expertise and lessons learned to collaborate with SpaceX on the development of approaches to monitoring and attenuating photometric luminosity.” SpaceX will in turn share its own analysis on the subject with NASA, so that the space agency can update its own guidance for future launches more generally.