Featured Image Source: SpaceX
SpaceX plans to offer broadband internet services globally to fund its space program. The network is called Starlink, it will be a constellation of 12,000 internet-beaming satellites. Currently, there is a total of 420 Starlink satellites in low Earth orbit. SpaceX teams are ready to deploy another cluster of 60 internet-beaming Starlink satellites to low Earth orbit today, June 3rd. A previously-flown Falcon 9 rocket is awaiting on Launch Pad 40 at Cape Canaveral, Florida. Liftoff is scheduled for Wednesday at 9:25 p.m. Eastern Time.
Astronomers have voiced their concerns over Starlink fleets appearing too bright right after deployment. The fleet of Starlink satellites navigate at lower altitudes during the first couple of weeks, making them visible to the naked eye. The reflectivity is due to the sun’s light hitting the satellites’ solar panel and antenna arrays. It can take over three weeks for all satellites to reach their operational, higher-altitude(s) to reduce reflectivity. The network’s initial phase, is to deploy about 1,584 satellites into an altitude of 550-kilometers above Earth. To address these concerns, SpaceX is working with senior members of the astronomy community to come up with a potential solution to make the satellites less visible from the ground. "SpaceX is launching Starlink to provide high-speed, low-latency broadband connectivity across the globe, including to locations where internet has traditionally been too expensive, unreliable, or entirely unavailable," SpaceX wrote in a statement:
"We also firmly believe in the importance of a natural night sky for all of us to enjoy, which is why we have been working with leading astronomers around the world to better understand the specifics of their observations and engineering changes we can make to reduce satellite brightness."
SpaceX engineers previously deployed a ‘DarkSat’ which featured an anti-reflective dark coating to test out. The DarkSat did make the satellite less reflective but the coating could cause thermal changes that affect the satellites’ signal performance. Now, engineers have developed a new potential solution to mitigate reflection and reduce satellites’ brightness. Today, they will launch an experimental Starlink ‘VisorSat,’ which is a satellite featuring a “deployable visor” that is attached to the satellite that works as a sunshade. VisorSats will be made up of a radio-transparent foam material. This would shield from the sun’s rays and minimize the potential for reflection on the satellites' chassis where the antennas are located.
“The key to making Starlink darker is to prevent sunlight from illuminating these white surfaces and scattering via reflection toward observers on the ground,” SpaceX explained, “Satellites are visible from the ground at sunrise or sunset. This happens because the satellites are illuminated by the Sun but people or telescopes on the ground are in the dark. These conditions only happen for a fraction of Starlink's 90-minute orbit.” The company aims to test out how well this new feature works this month, if it operates well, engineers will equip the entire next satellite fleet with a deployable visor - VisorSat.
To reduce satellites’ brightness SpaceX also plans to reorient the satellites as they move into higher orbits. The company says their goal is to make Starlink fleets “generally invisible to the naked eye within a week of launch” by modifying the satellite orientation to minimize the potential of reflectivity. “We're doing this by changing the way the satellites fly to their operational altitude, so that they fly with the satellite knife-edge to the Sun. We are working on implementing this as soon as possible for all satellites since it is a software change,” SpaceX stated. The ‘knife-edge’ of each satellite will be faced towards the sun as the satellite moves during orbit raise. This will minimize the sunlight's reflection.
SpaceX plans to offer Starlink broadband internet connection in northern parts of the United States and Canada before this year ends. Public beta tests will initiate in the northern hemisphere in about five to six months.