SpaceX on January 29 launched its fourth Starlink mission, lofting a further 60 satellites into space and increasing its number of satellites in orbit to 240 as it continues to expand its mega constellation.

The SpaceX Falcon 9 rocket lifted off from Cape Canaveral in Florida with the satellites on board. Each weighs an estimated 260 kilograms, with the entire payload of the rocket totalling more than 15,000 kilograms.

About eight minutes after launch, the first stage of the rocket returned for a landing on the drone ship Of Course I Still Love You (OCISLY) in the Atlantic Ocean. This first stage booster had previously flown twice before, the Crew Dragon demonstration mission to the International Space Station (ISS) in March 2019 and the RADARSAT mission in June 2019.

The satellites will be deployed at an altidue of 290 kilometers, where they will be checked to ensure they are working properly. If everything is fine, the satellites will then use their onboard ion thrusters to raise to their operational altitude of 550 kilometers over the next few months.

The plan for Space X is to ultimately launch 12,000 Starlink satellites into its constellation, designed to beam high-speed internet anywhere on Earth, with the possibility of a further 30,000 to follow. This year alone the company is planning 24 launches, totalling around 1,500 satellites.

SpaceX hopes to start operating its Starlink service for customers in the Northern U.S. and Canada later in 2020, with global coverage beginning in 2021. The price of the service has not yet been revealed.

Many experts have warned that the rapid increase in satellites planned by SpaceX and other companies, such as Amazon in the US and OneWeb in the UK, will make operations in Earth orbit difficult if proper care is not taken.

SpaceX claims that its constellation “is on the leading edge of on-orbit debris mitigation, meeting or exceeding all regulatory and industry standards.” The company notes that its satellites use their onboard propulsion systems to deorbit and burn up in Earth’s atmosphere and, in the event any satellites were to fail, they would re-enter within one to five years.