WASHINGTON — SpaceX launched another set of Starlink satellites Feb. 25 as the company argues its satellite constellation is consistent with the safe and sustainable use of low Earth orbit.
A Falcon 9 lifted off at 12:12 p.m. Eastern from Space Launch Complex 4E at Vandenberg Space Force Base in California. The rocket deployed its payload of 50 Starlink satellites into an orbit at an altitude of about 315 kilometers a little more than an hour later.
The Falcon 9 first stage landed on a droneship in the Pacific Ocean downrange of Vandenberg nearly nine minutes after liftoff. The booster previously launched the Sentinel-6A Michael Freilich and Double Asteroid Redirection Test (DART) spacecraft for NASA as well as one Starlink mission.
SpaceX noted in its webcast of the launch that it is now offering services in 29 countries, most recently Brazil and Bulgaria. The company also worked with the government of Tonga to provide connectivity after a volcanic eruption in January broke submarine cables providing internet connectivity for the Pacific island nation. While the main international cable serving Tonga has been repaired, the government is using Starlink antennas to provide connectivity to outlying islands where cables may not be repaired for months.
Starlink’s sustainability case
This launch came four days after another Falcon 9 launched 46 Starlink satellites from Cape Canaveral, Florida. The company now has 1,970 Starlink satellites in orbit, a constellation far larger than any other satellite system today.
SpaceX is seeking permission from the Federal Communications Commission to place as many as 30,000 next-generation Starlink satellites into orbit, prompting objections and other criticism. One example was a Feb. 8 letter from NASA outlining its concerns about SpaceX’s proposal, such as increased conjunctions between Starlink satellites and other space objects as well as interference with satellite and ground-based science.
In an apparent response to that criticism, SpaceX published Feb. 22 a lengthy statement arguing that it is committed to space sustainability. “SpaceX has demonstrated this commitment to space safety through action, investing significant resources to ensure that all our launch vehicles, spacecraft, and satellites meet or exceed space safety regulations and best practices,” the company wrote.
It cited as proof of that commitment designing “highly reliable, maneuverable” satellites designed to break up completely upon reentry; placing satellites initially in very low orbits after launch for initial checkouts; operating the entire constellation at altitudes below 600 kilometers, so that satellites will naturally reenter within 25 years of the end of their life if they are not deliberately deorbited; and the use of an autonomous collision avoidance system.
While the statement largely reiterated past arguments by the company about the overall safety of the Starlink system, it did offer some new data points. SpaceX said that Starlink satellites performed 3,300 collision avoidance maneuvers in the second half of 2021, with more than 1,600 involving close approaches to debris and 1,400 with other satellites. Each Starlink satellite is designed to “duck” to avoid potential collisions by moving its large solar array to create the smallest possible cross-section to an approaching object. Doing so can further reduce the odds of a collision by a factor of 4 to 10.
SpaceX said it has the ability to build 45 satellites, the approximately payload of a single launch, per week. Of the more than 2,000 satellites launched to date, SpaceX claimed only 1% have failed after going into their operational orbits. The company said it can deorbit a satellite within four weeks by first using onboard propellant to lower its orbit then initiating a “high drag mode” to maximize atmospheric drag for reentry.
“SpaceX has safely deorbited over 200 satellites utilizing this approach,” the company said. “By building reliable, debris minimizing satellites, planning for active deorbit and designing for full demisability, we ensure we’re keeping space sustainable and safe.”