SpaceX launched again on Thursday – this time to put a Spanish radar satellite above the Earth. But there was a lot of interest also in the mission’s secondary payloads – a couple of spacecraft the Californian rocket company will use to trial the delivery of broadband from orbit. SpaceX has big plans in this area.
By sometime in the mid-2020s, it hopes to be operating more than 4,000 such satellites, linking every corner of Earth to the internet. Wednesday’s flight was the first for SpaceX since the dramatic debut on 6 February of its Falcon Heavy – the world’s most powerful launcher. This time, it was the turn of the smaller workhorse, the Falcon-9.
It lifted clear of the Vandenberg Air Force Base on the US Pacific west coast at exactly 06:17 (14:17 GMT). The precise timing was needed to ensure the PAZ radar satellite, to be managed by Madrid-based Hisdesat, was dropped off in the right part of the sky. The new Earth observer is to team up with a German pair of spacecraft, Tandem-X and TerraSAR-X, which are already in orbit.
As a trio they will image the planet’s surface, seeing features as small as 25cm, even when there is heavy cloud in the way. The ascent to orbit and release of the PAZ platform took just 10 minutes. SpaceX made no attempt to recover the first-stage booster from the Falcon-9, allowing it to fall into the ocean. The rocket segment had previously flown last year.
Of more interest to SpaceX on this occasion was the release of the pathfinder satellites for its planned Starlink broadband network. In 2016, it filed an application with the Federal Communications Commission in the US for a licence to operate a “mesh network” in the sky consisting of 4,425 satellites arranged in 83 orbital planes. These spacecraft would be positioned at altitudes ranging from 1,110km to 1,325km, and transmit in the Ku and Ka portions of the radio spectrum. The company would like also to put up an additional 7,500 satellites that would sit under the initial set and transmit in the V-band.
Original Article: http://www.bbc.co.uk/news/science-environment-43160073