Elon Musk says SpaceX Starlink satellites 'albedo will drop significantly on almost every successive launch'

Featured Image Source: SpaceX Starlink

SpaceX plans to fund future missions to the moon and Mars by offering Starlink internet services. The rocket company is in the process of building a constellation consisting of approximately 1,584 internet-beaming satellites in low Earth orbit, they have approval from the Federal Communications Commission (FCC) to operate as many as 12,000 satellites. SpaceX aims to conduct 24 Starlink launches this year carrying 60 satellites each, which will enable them to begin offering services to some parts of Canada and Northern United States by the end of the year. The rocket company deployed the fifth batch of 60 Starlink satellites on Monday (February 17) bringing the constellation to a total of 290 satellites into low Earth orbit.

Successful deployment of 60 Starlink satellites confirmed! pic.twitter.com/bKBtI5UZEB

— SpaceX (@SpaceX) February 17, 2020

SpaceX's Starlink broadband internet satellites could benefit the world in a variety of ways. Starlink's satellite internet will transmit its signal faster to anywhere on the planet at the speed of light, bypassing the limitations of our current internet infrastructure. Every deployment of 60 satellites could deliver 1 terabit of bandwidth, that could potentially support 40,000 users streaming ultra-high-definition content at the same time. Starlink's broadband internet will be affordable enough that areas in the world where internet is non-existent, or unreliable will benefit from their service. Starlink could open a whole new era of educational and business opportunities to areas on our planet where terrestrial internet communications have been expensive or too difficult to build. According to SpaceX officials, Starlink customers will receive internet connection from space via a small terminal that "looks like a thin, flat, round UFO on a stick," meaning it is a circular shape antenna attached on a stick to lift the unit up.

Astronomers have been sharing their concerns about Starlink satellites appearing too bright in the night sky and how a constellation could interfere with their astronomical observations. Starlink is launched in batches of 60 satellites per mission, they are especially bright soon after launch, visible in train-like formations when flying at lower altitudes, before reaching their final -higher- orbit, where they should become less visible from the ground to the naked eye.

When initially launched into an altitude of about 300 kilometers, the satellites' are bright enough to be easily seen by the naked eye, even in a city filled with light pollution. By the time they get to their operational orbit of 550 kilometers, the satellites become dimmer and are visible to the naked eye only in much darker skies away from city lights. SpaceX says the satellites' reflectivity was a surprise to the company and that engineers are actively working to find a solution to decrease Starlink satellites' brightness. "We certainly knew this was a novel spacecraft design in a novel architecture, but the level of brightness and visibility was a surprise to us," said Patricia Cooper, vice president of satellite government affairs at SpaceX, who represented the company at the recent American Astronomical Society (AAS) meeting.

Last month on January 6, they deployed one satellite with an experimental anti-reflectivity coating on the bottom, called DarkSat. “This next batch has one satellite that we’ve put a coating on the bottom. This is going to be an experiment … We’re going to do trial and error to figure out what’s the best way to get this done. But we are going to get it done,” SpaceX President Gwynne Shotwell stated. First, engineers plan to test DarkSat's coating to see if its anti-reflectivity properties could cause thermal changes that could affect the satellites internet signal performance. The Founder and CEO of SpaceX Elon Musk, was asked via Twitter -"How does the starlink test satellite designed to reduce the albedo [brightness] feel?" To which Musk responded:

 

"[Starlink satellites] albedo will drop significantly on almost every successive launch."

 

🛰 albedo will drop significantly on almost every successive launch

— Elon Musk (@elonmusk) February 15, 2020

The DarkSat, that was launched in January, is expected to raise into an operational (higher) orbit sometime by the end of February, as soon as it reaches higher orbit of around 550 kilometers above Earth, engineers will test how the anti-reflective coating may affect the satellite's connectivity performance.The Starlink constellation will be deployed into three orbital shells with operational altitudes of 340 kilometers (210 miles), 550 kilometers (340 miles) and 1,150 kilometers (710 miles). DarkSat's orbit is still low, at about 366 - 368 kilometers. 

SpaceX engineers are working alongside astronomers to observe and measure the effectiveness of the DarkSat anti-reflectivity coating, Musk assured:

"We’ve had good discussions with leading astronomers. One way or another, we’ll make sure Starlink doesn’t inhibit new discoveries or change the character of the night sky."

It will take a couple of months for the company to test out and decide whether to apply the anti-reflective coatings to all future Starlink satellites, or if they will test out other experimental DarkSats before figuring out a final solution.