SpaceX is fresh of its historic crewed launch that sent astronauts Bob Behnken and Doug Hurley to the International Space Station (ISS), but it’s not taking any time off to celebrate. The company has just launched yet another batch of Starlink internet satellites, and it did so with one of the “most reused” rockets in history.
SpaceX has been successfully recovering Falcon 9 boosters for several years, allowing it to lower the cost of launches. While the NASA launch over the weekend relied on a shiny new Falcon 9 (complete with NASA worm logo), the most recent Starlink mission used a sooty refurbished rocket. The core (B1049) has survived four previous launches; two Starlink launches, a mission to deploy the Telstar 18V communication satellite, and a load of Iridium NEXT satellites. The satellites reached orbit as planned, but the booster missed the drone ship and crashed into the ocean. Still, that’s four more launches than any other rockets are getting.
SpaceX is already the single largest satellite operator in the world, and the network will grow considerably over the next few years. It has approval to put 12,000 satellites in orbit, but it may eventually get permission to launch more. As with past Starlink launches, this mission deployed 60 new satellites to SpaceX’s mega-constellation. That brings us to 482 active satellites, which is more than the 400 satellites CEO Elon Musk predicted the company would need for basic internet services in select regions. Moderate coverage will require about 800 nodes.
The Starlink constellation will mostly operate in low-Earth orbit, but some will remain in very-low Earth orbit (VLEO) to improve latency. Existing satellite internet connections can have a latency of several seconds, which makes real-time web applications impossible. SpaceX says Starlink, which will operate in the Ka and Ku bands, could offer latency as low as 15ms. That’s low even for terrestrial wired broadband.
Astronomers have expressed concern over the effect all these satellites will have on observations of the sky. In early 2020, a team from the CTIO observatory in Chile lost 15-20 percent of the data from an image of the Magellanic Clouds. SpaceX’s solution is a system called VisorSat, which consists of small fins that deploy on the satellites to block sunlight from reflecting down to Earth. Today’s launch was the first to use VisorSat, but it will take time to find out how well it works.