Earth’s orbit began to appear crowded, so NASA and SpaceX signed a joint agreement that would see satellites such as the Starlink constellation automatically move away from NASA’s devices. The new policy aims to avoid collisions between fast-moving objects in space, which may be expensive or even life-threatening in the future.
It’s an increasingly timely challenge, given SpaceX’s rapid deployment of Starlink satellites. The company aims to cover the planet with an internet connection from a constellation of satellites, and it has launched multiple packages in recent months. This will likely increase in frequency once the SpaceX spacecraft is deemed ready to take over the launch missions.
The problem is, the space may be large but the area around the Earth is getting more and more crowded. “The focus of the agreement is to avoid coupling and collision between NASA’s spacecraft and a large group of SpaceX Starlink satellites.” NASA said Today, “In addition to the relevant trip sharing tasks.”
NASA has the easiest part. The agreement effectively states that it will not handle its assets in the event that a potential crash is expected, unless SpaceX tells it otherwise. Meanwhile, the Starlink satellites will be distanced by any NASA satellites or other assets. This process will be performed either independently or manually.
Each Starlink satellite is equipped with a Global Navigation Satellite Service receiver, which tracks its orbit. They can use ion propulsion systems to maneuver independently.
NASA is currently evaluating trajectory data from both the Space Observation Network that tracks objects in orbit, and the Recording Service operated by the US Air Force’s 18th Space Control Squadron, known as SPCS 18. The space agency is looking forward to roughly one week, to map out any potential close approaches that could take place and to develop a mitigation plan.
This could involve potential collision hazards to the International Space Station (ISS) and any spacecraft carrying personal personnel, as well as any non-human spaceflight missions.
“NASA will operate on the basis that the autonomous maneuverability of the Starlink satellites will attempt to maneuver to avoid association with NASA assets, and that NASA will maintain its planned course unless notified by SpaceX.” the agreement States. “There may be situations, such as launch or other guidance anomalies in Starlink orbit, navigation and control, or anomalies in the propulsion system, where Starlink satellites maneuvering around NASA assets may not be a viable option and NASA assets must maneuver.”
Part of the agreement sees SpaceX agree to choose Starlink launch injection orbits at least 5 kilometers (3.11 mi) above or below the peak or perihelion point of the International Space Station. If this is not possible, NASA is expected to be informed within one week of determining the altitude.
Meanwhile, the agreement also appears to be exploring ways in which SpaceX can address one of the ongoing criticisms of the Starlink system: the extent to which satellites are visible from Earth. The glow of light reflected off the constellation caused widespread concern among amateur and professional astronomers, leading the private space exploration company to look for ways to make it less reflective.
The agreement with NASA includes a commitment to “share technical expertise and lessons learned to collaborate with SpaceX in developing methods for monitoring and mitigating luminous brightness.” SpaceX will in turn share its own analysis on this topic with NASA, so that the space agency can generally update its guidance for future launches.