Earlier today, SpaceX successfully launched and deployed its first two test satellites for Starlink, the rocket company's own constellation of thousands of communications satellites that aims to provide world wide broadband internet access by 2024.
TheFalcon 9 rocket lifted off at 14:17 UTC from SpaceX's Vandenberg, California launch site, heading south over the Pacific Ocean to achieve a near-polar orbit. The first stage separated from the rest of the rocket some three minutes later, but, in what is now an uncharacteristic move for SpaceX, no attempts were made to recover it. (The reason? The booster was an outdated"Block 3" version, and the company is in the process of clearing its large stock of recovered first stages as it prepares to debut its more advanced, more reusable "Block 5" version in upcoming launches.)
The rocket's primary payload was Hisdesat's PAZ satellite, an advanced imaging satellite with up to 25 cm (10 in) resolution that will cover an area approximately the size of Italy every 24 hours.
Of greater interest, however, was the secondary payload: two smaller test satellites, baptized "Tintin A & B," and forming the vanguard of what SpaceX hopes will be its very own constellation of high-speed internet communications satellites.
The Starlink project was announced by SpaceX in January 2015, just as Google andFidelity invested US$1 billion into Musk's private space company. It proposes to launch a very large number (as many as 12,000) of small communications satellites in low Earth orbit. These satellites would operate in concert within the microwave band of the electromagnetic spectrum to provide low-latency, broadband internet anywhere in the world.
Low-altitude orbits are a crucial part of the plan to achieve fast and responsive data connections. Today's communications satellites have high latency because they are parked in geostationary orbit, 35,800 km (22,300 mi) above sea level: at that distance, a light-speed signal takes a minimum of 0.23 seconds for a round trip. By operating in low Earth orbit, Musk's network would cut that distance by a factor of 30 to 100.
According to FCC filings, SpaceX aims to launch a whopping 4,425satellites by 2024 in a 1,200 km (750 mi) orbit. After that, the rocket company plans to add another seven thousand in a much lower340 km (210 mi) orbit, to provide latency comparable to that of fiber optics. Because of the large number of satellites involved, SpaceX has already had to provide assurances to the relevant authorities, hashing out details on how the satellites will be deorbited at the end of their useful life so they won't end up an unmanageable pile of space junk.
SpaceXis by no means the only company pursuing a global, low-latency communications network: Boeing, Facebook, Samsung, and OneWeb, among others, have also advanced similar plans for large swarms of low Earth orbit satellites. However, because of its unmatched reusable rocket technology, Musk's company is likely the one with the best shot at deploying its satellite network in a cheap and timely fashion.
Fairing recovery attempt just misses mark
Incidentally, today's launch also marked another important step in SpaceX's rocket reusability efforts, which could further cut its launch costs. As the mission was still in progress, Musk tweeted that the rocket's fairing – a costly piece of equipment (estimated at US$6 million) that protects the payload from aerodynamic forces on ascent and is jettisoned when the rocket reaches space – was able to survive atmospheric reentry and was very nearly recovered by a dedicated "catcher's mitt" boat.
This was achieved thanks to a new iteration of the payload fairing, which includes small thrusters and parachutes to orient and direct the precious piece of equipment toward the recovery boat. Unfortunately, the fairing splashed down a few hundred meters from its intended target, but this partial success bodes well for future efforts. The first stage is estimated to make up 70 percent of the US$60 million price tag of a Falcon 9 rocket; recovering the fairing could help cut launch costs by another 10 percent.
Musk said the two Starlink test satellites have deployed correctly and are communicating to Earth stations. The next attempt at fairing recovery will be in about a month.
Source: SpaceX