When it comes to SpaceX, Elon Musk’s Space Exploration Technologies Corp., we often think about futuristic spaceships sending civilians to Mars, or cargo spacecrafts shuttling astronauts back and forth between earth and the International Space Station. However, along with these exciting endeavors, SpaceX also has its fair share of satellite launches that have helped improve our GPS systems exponentially. As recently as October 18, 2020, they launched a full stack of 60 Starlink internet satellites into space using a Falcon 9 rocket, the first privately funded liquid-propellant rocket to reach earth’s orbit. Musk hopes to launch as many as 12,000 satellites in total to complete Starlink, their comprehensive satellite constellation. Each Starlink satellite uses GPS III technology, weighs 500 lbs (227 kilograms), and is roughly the size of a table. Starlink uses SpaceX rockets to launch their satellites into space with the aim of providing a global satellite-powered internet.
SpaceX GPS Satellite Launches
The previous generation’s GPS II satellites, first deployed in 1989, were the first full-scale operational GPS satellites. The current generation’s GPS III satellites launched in December of 2018, were built by Lockheed Martin and have three times better accuracy and up to eight times improved anti-jamming capabilities.
GPS III satellites are intended to be more user-friendly for civilians. They feature a new “civil signal” to allow easier communication with other satellite navigation systems including Europe’s Galileo constellation of more than two dozen satellites. This will allow civilians to have more satellites in their system operating above them at any given moment.
The new GPS III satellites are intended to gradually replace the older GPS II satellites currently in orbit. So far, SpaceX has launched two GPS satellites. The third was due to be launched on October 2, 2020, but was aborted just two seconds before takeoff. According to Musk, this was due to an “unexpected rise in the turbo machinery gas generator” in the rocket’s main engines. In the meantime, five more GPS III satellites are in production, three of which have been completed and are undergoing testing.
Falcon 9 Starlink Launches
SpaceX carries out Starlink satellite launches using their own Falcon 9 rockets. First flown in June 2010, the Falcon 9 is a two-stage liquid-rocket incorporating a reusable first stage and an expendable second stage. After each launch, SpaceX guides the reusable first stage to land on one of its two floating drone ships in the Atlantic Ocean, quirkily named “Of Course I Still Love You” and “Just Read the Instructions.”
In May of 2018, SpaceX debuted an upgraded version of its rocket, the Falcon 9 Block 5, featuring an improved thermal protection system, new titanium grid fins, and engines packing over 1.7 million pounds of thrust. To date, the Falcon 9 rockets have launched 98 times with only one in-flight failure. Each launch has been orbital, except for a test launch in 2019 for an unscrewed SpaceX Dragon spacecraft. With its proven track record, the Falcon 9 has been contracted to launch both military and national security payloads.
SpaceX has been launching GPS III satellites using Falcon 9 rockets since December 2018. Falcon 9 deploys the satellites into a 1,200 by 20,000 kilometer transfer orbit at an inclination of 55 degrees to the equator. The satellites then use their own propulsion to attain an operational orbit at 20,000 kilometers in altitude.
Aborted GPS Launches
SpaceX has recently suffered a number of aborted launches. A GPS III launch was first scheduled for September 29, 2020. The launch was delayed until September 30th for improved launch and recovery weather.
On September 30th there was a further cancellation due to a range conflict. The conflict may have been with the United Launch Alliance Delta IV Heavy rocket or the Northrop Grumman Antares rocket to the International Space Station. A new date of October 2nd was set.
On October 2nd, just two seconds before liftoff, SpaceX aborted the launch of their Falcon 9 rocket carrying a GPS III satellite for the United States Space Force. At the time, SpaceX did not give an explanation for their decision. It was not clear if there was an issue with the rocket or the ground support systems.
SpaceX Satellites: Starlink Constellations
SpaceX has ambitions to complete their Starlink satellite constellation to provide an affordable, high-speed internet reaching all corners of the globe, including rural and remote areas. The initial plan was to launch a fleet of 1,440 satellites, but SpaceX has since obtained approval for thousands more.
The Federal Communications Commission has granted SpaceX permission to launch 12,000 satellites, but SpaceX’s ambitions do not stop there. They plan to seek approval to launch a further 30,000 internet-beaming satellites to provide high-speed, low-latency internet coverage.
Users will be able to connect to the Starlink satellites with a Starlink Terminal, which Elon Musk has described as resembling a “UFO on a stick.” According to CNBC, the user terminals are easy to use and can be set up within a few minutes.
Some newer Starlink satellites feature inter-satellite links which SpaceX has described as “space lasers.” Space X says their tests have shown that the space lasers can transfer hundreds of gigabytes of data, making Starlink one of the fastest technologies for transferring data around the world.
Future of SpaceX Satellites
Starlink satellite launches have treated skywatchers to the sight of a brilliant trail of moving lights in the night sky, resembling a string of pearls. SpaceX satellite tracker apps and sites informed eager skywatchers when and where to look, including Star Walk’s Satellite Tracker, Heavens Above, and CalSky.
The excitement of the skywatchers was not shared by the astronomical community. Alarmed researchers shared photos of satellite streaks in their data, warning that they could ruin images from highly sensitive telescopes. Additionally, as the satellites communicate with Earth via radio signals, they increase radio chatter, which affects radio astronomy projects such as the Event Horizon Telescope’s imaging of a black hole.
These concerns prompted the International Astronomical Union to issue a statement in June 2019, urging designers of SpaceX to work with the astronomical community to understand the impact of satellite constellations on important astronomical infrastructures.
SpaceX received further backlash in September 2019 when the European Space Agency (ESA) announced that its Aeolus satellite was forced to perform an evasive maneuver to avoid crashing into “Starlink 44,” one of the first satellites in SpaceX’s satellite constellation. It was reported that SpaceX did not respond to requests to move its satellite out of the way.
SpaceX is working to resolve the concerns raised about its satellite constellation, and stated it will work with organizations and space agencies to mitigate its impact on the night sky. In January 2020, SpaceX launched a redesigned Starlink satellite named DarkSat, featuring an experimental coating to make it less reflective.
The huge increase in numbers of satellites from not just SpaceX but other private space companies such as OneWeb suggests that warnings about potential collisions will persist. Greater regulations may be the way forward, as the Federal Aviation Administration proposed new rules for space launches to promote greater safety in October of 2020.
Whatever the challenges it faces, SpaceX will seek to find a way to overcome them. The scale of Musk’s ambition regarding SpaceX’s satellite constellation is not in doubt. In the words of Musk, “We’re really talking about something which is, in the long term, like rebuilding the internet in space.”