Credit: Adobe Stock

WASHINGTON — An updated version of a space safety document endorsed by more than two dozen organizations includes “rules of the road” for avoiding collisions between space objects.

The updated “Best Practices for the Sustainability of Space Operations” document, published by the Space Safety Coalition (SSC) April 4, is a major revision of the guide for satellite operators to minimize the risks of collisions in orbit.

One of the biggest changes in the document is the inclusion of rules of the road for coordinating maneuvers between objects. The report describes five classes of objects — nonmaneuverable, minimally maneuverable, maneuverable, objects with automated collision avoidance and crewed spacecraft — and outlines rules they should follow when a collision avoidance maneuver involving two of them is required.

In general, maneuvers are prioritized in favor of more sophisticated spacecraft unless other arrangements are in place. For example, in an encounter between a maneuverable spacecraft and one with automated collision avoidance, the latter will maneuver. Special coordination may be needed in cases of encounters between two spacecraft in the same category.

The rules outlined in the report stemmed from interest among governments in establishing similar binding rules in national regulations. “They want to come up with rules of the road, but they’re not actually flying the satellites, so they don’t have that keen insight on what rules of the road would work, at least commercially,” said Dan Oltrogge, founder and administrator of the Space Safety Coalition, in an interview.

He noted that many commercial satellite operators coordinate with one other, and the rules laid out in the document are based on that experience. “We came up with this approach to have something that we could build upon, but had the essential elements.”

The rules are modeled to a degree on maritime “give way” rules, where smaller, more maneuverable boats would move to avoid larger ships that cannot change course as quickly. One difference, he noted, is that it can be harder to tell when a spacecraft has maneuvered, since data on its orbit may not be updated quickly.

The rules are not intended to replace coordination among operators. “We could make all the rules of the road we want, but unless we emphasize coordination, first and foremost, we’re missing the boat,” Oltrogge said.

The rules of the road are not the only changes to the document. It specifically calls on satellite operators to avoid intentional fragmentation, which stemmed from the Russian anti-satellite weapons test in 2021. “There’s a lot of strong feelings of avoiding intentional fragmentation via collision, explosion or just released debris objects,” he said.

It references updated international guidelines and standards regarding space sustainability and debris mitigation, as well as cybersecurity to prevent unauthorized access. There are updated guidelines for disposing of spacecraft at the end of their missions, including increased reliability for such efforts and the timing for “passivation” of spacecraft to prevent debris-generating explosions.

As of the release of the updated version, 27 companies and organizations had endorsed the document. It includes major GEO satellite operators Inmarsat, Intelsat and SES as well as LEO satellite operators Iridium and Planet.

“These best practices clearly set aspirational targets to encourage all space actors to advance towards a safer, more responsible and sustainable use of space,” said Charles Law, senior manager of flight dynamics at SES, in a statement. “Importantly, these best practices seek to stop intentional collisions and fragmentations, and it is encouraging to see a framework to coordinate between maneuverable satellites and to exchange orbit information.”

Oltrogge noted the older version of the guidelines had been endorsed by 60 organizations, and that the SSC was working to get them and others to sign on to the new version. “I know a number of operators who are actively reviewing and probably will be signing on very shortly,” he said.

He described the report as a living document that will continue to change. “I may take a little breather,” he said, “but the space environment is evolving so fast that we really cannot afford to take much of a breather.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...