SpaceX launches fourth batch of Starlink satellites, tweaks satellite design
WASHINGTON — SpaceX completed its second Starlink launch of the month Jan. 29, conforming to a target cadence the company set last year to launch two dedicated Starlink missions monthly throughout 2020.
SpaceX’s Falcon 9 rocket lifted off at 9:07 a.m. Eastern from Cape Canaveral Air Force Station, Florida, with another 60 Starlink internet satellites. The rocket’s upper stage deployed the satellites into a 302-kilometer low Earth orbit about an hour after liftoff.
SpaceX said it will test its satellites around that low altitude, where it expects any failures would burn up in Earth’s atmosphere after a few months. After completing checkouts, SpaceX plans to raise the satellites to a 550-kilometer operational orbit.
The launch — SpaceX’s fourth for Starlink not counting two demonstration satellites launched in 2018 — carried an upgraded set of satellites designed for better spectral efficiency and throughput. Poor weather delayed the mission by about a week.
Falcon 9’s first-stage booster landed on the droneship “Of Course I Still Love You” in the Atlantic Ocean, completing its third trip to space. SpaceX previously used the booster to launch the company’s Crew Dragon capsule on a March 2019 demonstration mission for NASA, and to launch three Canadian radar satellites last June.
SpaceX successfully caught a payload fairing half with “Ms. Tree,” a boat equipped with a large net. Jessica Anderson, a SpaceX manufacturing engineer co-narrating the launch, said the second fairing half missed its recovery boat, “Ms. Chief,” but appeared to have a soft water landing.
“We will be pulling that fairing half out of the water and hopefully reusing it again in the future,” she said.
Changes to Starlink
SpaceX has now launched 242 Starlink broadband satellites, though not every satellite will be part of the constellation when it starts service, a milestone anticipated later this year in Canada and the United States.
Some 10 Starlink satellites have not raised their orbits, according to observations by Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who tracks satellite movements.
SpaceX spokesman James Gleeson, when asked about the 10 satellites, said SpaceX is “performing a controlled de-orbit of several first iteration Starlink satellites,” using onboard propulsion.
“While these satellites are operable and capable of providing service, the second iteration of Starlink satellites that SpaceX has started to deploy provide better spectrum efficiency, more capacity and optimized service to the end user,” he said.
SpaceX’s Starlink satellites launched Jan. 29 each weigh approximately 260 kilograms, an increase of 33 kilograms from the 60 satellites launched in May 2019.
SpaceX specified that the newest Starlink satellites have four phased array antennas. Previous satellites were described as having “multiple” phased array antennas.
SpaceX has been modifying Starlink’s design since early on in the program. The first 60 satellites were described as 95% demisable upon atmospheric reentry, meaning some components risked reaching the Earth’s surface. By the second dedicated launch in November, Starlink’s design featured fully demisable parts.
SpaceX is also experimenting with ways to lessen Starlink’s impact on astronomy. Earlier this month the company launched a satellite nicknamed “DarkSat” that features a darkening coating to make it less visible to stargazers and ground-based observatories.
SpaceX CEO Elon Musk said in May 2019 that later versions of Starlink would include inter-satellite links. He said then that the company would like to keep Starlink satellites in orbit for four to five years before deorbiting and replacing them with newer, more capable models.