Featured Image Source: SpaceX
SpaceX successfully deployed another cluster of 60 internet-beaming Starlink satellites on Wednesday, April 22, bringing the overall total to 420 satellites in low Earth orbit (excludes 2 experimental satellites which will be deorbited). The network will be made up of over 12,000 satellites. The initial phase of deployment consists of operating 1,584 satellites at an altitude of 550-kilometers above Earth, inclined 53 degrees to the equator. The company aims to roll-out service in portions of the Northern United States and Canada after deploying approximately 800 satellites. Starlink satellites are launched atop a Falcon 9 rocket in batches of 60, soon after launch the satellite fleet looks bright in the night sky for weeks until they raise into a higher orbit. People from around the world have even reported the Starlink string of lights as 'UFO sightings.' Astronomers have voiced their concerns over ‘Starlink appearing too bright.’ SpaceX is actively working with senior members of the Astronomy community to minimize the potential reflection of the satellites. The company wrote on Friday:
“SpaceX is committed to promoting all forms of space exploration, which is why it has already taken a number of proactive steps to ensure it does not materially impact optical astronomy. […] SpaceX is working with U.S. and international astronomy organizations and observatories to measure scientifically the actual impact of its satellites.”
Lately, the Starlink fleet has been visible across the world. The visibility is due to the sun’s reflection. Many have shared videos and photographs of the fleet online.
The Starlink satellite train in the sky above Kosovo on April 19, 2020 (source: Astrit Spanca )
In response to why the Starlink satellites appear to be brighter, the founder and chief engineer at SpaceX, Elon Musk, said, “Solar panel angle during orbit raise/park. We’re fixing it now.” So, the angle has caused the sun to produce more reflection towards Earth’s view. Each satellite is equipped with thrusters to move into different angles and orbits.
Solar panel angle during orbit raise / park. We’re fixing it now.— Elon Musk (@elonmusk) April 22, 2020
Engineers are experimenting with a variety of methods to reduce reflectivity. In January, they sent ‘DarkSat’, a satellite with an experimental anti-reflective coating. Last month, during a Starlink mission, they shared data indicated a “notable reduction” in DarkSat’s reflectivity. “SpaceX is developing new mitigation efforts that it plans to test in the coming months.” SpaceX states, “Additionally, SpaceX will make satellite tracking data available so astronomers can better coordinate their observations with our satellites.”
One of the new mitigation efforts SpaceX engineers are working on is a ‘sunshade,’ that will act as an umbrella to minimize brightness. “We are taking some key steps to reduce satellite brightness.” Musk shared, “Should be much less noticeable during orbit raise by changing solar panel angle & all sats [satellites] get sunshades starting with launch 9.”
Thanks! We are taking some key steps to reduce satellite brightness btw. Should be much less noticeable during orbit raise by changing solar panel angle & all sats get sunshades starting with launch 9.— Elon Musk (@elonmusk) April 22, 2020
Today Starlink’s seventh mission was conducted. In a couple of months, by the ninth mission, SpaceX expects to have a cluster of 60 satellites equipped with sunshades, in order to test out if it will work at reducing each satellites visibility from Earth. The sunshades will be made from “a special dark foam that’s extremely radio transparent,” so its anti-reflective properties do not interfere with the satellite’s internet-beaming capabilities to the ground stations and terminals on Earth. Musk revealed via Twitter:
“It’s made of a special dark foam that’s extremely radio transparent, so as not to affect the phased array antennas. Looks a lot like a car sun visor.”
It’s made of a special dark foam that’s extremely radio transparent, so as not to affect the phased array antennas. Looks a lot like a car sun visor.— Elon Musk (@elonmusk) April 22, 2020
Customers will require user terminals to receive Starlink’s broadband-internet connection from space. The Federal Communications Commission approved the operation of 1 million user terminals in the United States, Musk says beta testing will begin this year – “Private beta begins in ~3 months, public beta in ~6 months, starting with high latitudes.” The first tests will take place in the northern parts of the country.