The Federal Communications Commission has a plan to minimize space junk by requiring low Earth orbit (LEO) satellites to be disposed no more than five years after being taken out of service.
A proposal released yesterday by FCC Chairwoman Jessica Rosenworcel would adopt “a first-ever rule requiring non-geostationary satellite operators to deorbit their satellites after the end of their operations to minimize the risk of collisions that would create debris.” It’s scheduled for an FCC vote on September 29.
The five-year rule would be legally binding, unlike the current 25-year standard that’s based on a NASA recommendation proposed in the 1990s.
“Currently, it is recommended that operators with objects in LEO ensure that their spacecraft are either removed from orbit immediately post-mission or left in an orbit that will decay and re-enter Earth’s atmosphere within no more than 25 years to mitigate the creation of more orbital debris. However, we believe it is no longer sustainable to leave satellites in LEO to deorbit over decades,” the FCC proposal said.
The new rule “would require space station operators planning disposal through uncontrolled re-entry into Earth’s atmosphere to complete disposal as soon as practicable, and no more than five years following the end of mission,” an FCC fact sheet on the draft order said. The plan includes “a grandfathering period of two years for the new requirement to reduce any potential burden on operators.”
Current satellites exempt
Satellites already in orbit will be exempt from the new requirement if it’s approved as written. “For satellites already authorized by the Commission that have not yet been launched, we will provide a grandfathering period of two years, beginning on September 29, 2022, in order to allow operators to incorporate the five-year post-mission disposal requirement into their mission objectives,” the FCC said.
The rule would apply to US-licensed satellites. It would also apply to operators of non-US licensed satellites if they seek US market access, for example, by providing broadband service to US residents.
It will be possible to get waivers from the five-year plan on a case-by-case basis, particularly for scientific research missions. The FCC proposal said NASA “expressed concern that a five-year limit would impact NASA Science Mission Directorate’s (SMD’s) CubeSat missions, which rely on natural decay of orbit to manage post-mission orbital lifetime and impose greater limits on acceptable launch opportunities.” The five-year requirement “may be unduly burdensome” at certain altitudes, the FCC said.
Starlink’s plan should comply with new rule
SpaceX’s Starlink broadband division, the biggest operator of LEO satellites, would apparently comply with the new rule without any changes to current operations. Lower altitudes help speed up disposal: When SpaceX sought permission to use altitudes of 540-570 km instead of the 1,110-1,325 km it originally obtained approval for, it told the FCC that deorbiting from this lower range can be done in months.
SpaceX said its deorbiting sequence from 540-570 km would consist of an “active” phase that takes a few weeks for each vehicle and a “passive” phase that lasts several weeks to months, “with the exact time depending on solar activity.” In a worst-case scenario, the deorbiting would still take less than five years because of the lower altitude, SpaceX said:
“While SpaceX expects its satellites to perform nominally and deorbit actively as described above, in the unlikely event a vehicle is unable to finish its planned disposal maneuver, the denser atmospheric conditions at the 540-570 km altitude provide fully passive redundancy to SpaceX’s active disposal procedures. The natural orbital decay of a satellite at 1,110-1,325 km requires hundreds of years to enter the Earth’s atmosphere, but the lower satellites will take less than five years to do so, even considering worst-case assumptions.”
The FCC approved SpaceX’s plan to cut altitudes in half partly because the lower altitudes would make it easier to prevent buildup of orbital debris. The new five-year rule would apply to satellites in Starlink’s range and above, specifically to “space stations ending their missions in or passing through the low Earth-orbit region below 2,000 kilometers.”
Describing the debris problem, the pending FCC proposal said:
“Defunct satellites, discarded rocket cores, and other debris now fill the space environment creating challenges for future missions. Moreover, there are more than 4,800 satellites currently operating in orbit as of the end of last year, and the vast majority of those are commercial satellites operating at altitudes below 2,000 km—the upper limit for LEO. Many of these were launched in the past two years alone, and projections for future growth suggest that there are many more to come.”
Starlink has FCC permission to launch nearly 12,000 satellites. While currently orbiting Starlink satellites are in the 540-570 km range, about 7,500 of its approved satellites would orbit from 335 km to 346 km. SpaceX is also seeking permission for 30,000 more satellites in altitudes ranging from 340 km to 614 km.
OneWeb is operating LEO broadband satellites at an altitude of about 1,200 km, with deorbiting plans reportedly calling for disposal timelines of five years or less. Amazon plans to launch a few thousand satellites in altitudes of 590 km, 610 km, and 630 km. Ars Technica