What is that?! SpaceX’s Starlink Satellites Explained | Space

View photos from the EarthSky community. | Here at EarthSky, we receive many enthusiastic emails about sightings of lights traveling together across the night sky. UFOs? No. Usually people see Starlink satellites. Roger Oban in Tucson, Arizona took this photo from Starlinks on May 5, 2021. He wrote, “Shot in my backyard. I was about to stop, when 5 satellites arrived, all in a straight line. Thanks Roger!

Starlink is the name of a satellite network that SpaceX is developing to provide global broadband coverage for high-speed internet access, especially for people around the world living in rural and remote areas. SpaceX launched over 600 new Starlinks this year, typically launching 60 at a time. As of last week, that puts the number of Starlink satellites currently in orbit at over 1,500. Over the next few years, SpaceX plans to send at least 12,000 Starlink satellites. Satellite Internet is broadcast in space at a rate that would have 47% faster than fiber optic cable internet. Everything is fine. But Starlinks are brilliant. They can be seen in the night sky. Each launch creates what is called mega-stellations – groups of satellites moving together. Does the sudden increase in the number of Starlink satellites in 2021 also lead to an increase in UFO sightings? In addition, astronomers are worried. Starlink satellites photobomb astronomical images. They have the potential to interfere with the professional observations that have given us our modern view of the cosmos.

Starlink’s proposal announced by SpaceX CEO Elon musk in January 2015. Although not given a name at the time, Musk said the company had already filed documents with international regulators to place around 4,000 satellites in low earth orbit. He said in a speech during the revelation of the project:

We’re really talking about something that, in the long run, looks like rebuilding the Internet in space.

And his predictions so far have proven to be true. Musk’s initial estimate of the number of satellites rose rapidly, as he hoped to capture a portion of the global internet connectivity market estimated at $ 1 trillion. The United States Federal Communications Commission (FCC) granted SpaceX authorization to fly 12,000 satellites, and possibly up to 30,000 eventually. To put it in perspective: only about 2,000 operational satellites are currently orbiting the Earth. Fewer than 9,000 have ever been launched in all of history, according to the United Nations Office for Outer Space Affairs. Starlink satellites orbit at an altitude of 550 km. At this height, they’re low enough that they’ll be drawn to Earth by atmospheric drag and burn in a few years, so they don’t become space junk once they die (a problem SpaceX can hope to solve using Starship). ). Each weighs 500 pounds (227 kg) and is roughly the size of a typical coffee table, according to Skyandtelescope.com.

It was exciting to see the first Starlink satellites traveling together in the night sky. But then more were launched, and more. And astronomers started to worry.

A trail of opaque white lines crosses a starry sky, covering stars in the background.
View photos from the EarthSky community. | Vince tuboly in Hegyhátsál, Hungary, captured these roaming Starlink satellites on May 9, 2021 and captioned them: “New Starlink Satellites Series”.

SpaceX’s two test satellites, TinTinA and TinTinB, were launched in 2018. The mission went well. From this initial data, the company decided it wanted its fleet to run lower than expected. Regulators deliberated and the FCC approved the move.

The first 60 Starlink satellites were successfully launched on May 23, 2019 aboard a SpaceX Falcon 9 rocket. Starlink team members plan to launch up to 60 more per Falcon 9 flight, with launches as often as every two weeks in 2021. Of the 15 Falcon 9 launches so far this year, all have been dedicated to lofting 60 Starlink two satellites, bringing the total number launched so far this year to 722 so far. One – the Carrier-1 carpool mission in January – carried only 10 satellites, and the other – the Capella space carpooling mission launched last Saturday – scope 52.

Starlink controversy within the astronomical community. Despite the promise of high-speed, high-speed internet, SpaceX has faced criticism within the astronomical community for its Starlink satellites, due to their brightness and potential to disrupt night sky observations. The National Science Foundation and the American Astronomical Society published a report on the situation in August 2020. Discussions between more than 250 experts in virtual satellite constellations 1 (SATCON1) expressed concern that the luminous train of satellites marching in the sky would interfere with their observations.

In response, SpaceX began outfitting its satellites with a blackened sun visor – called VisorSat – that the company hopes to reduce the apparent brightness of the satellite by reducing the amount of reflected sunlight. This is just one of six suggestions offered by the SATCON1 team. The first efforts to mitigate the impact of the spacecraft were to launch a prototype Starlink satellite later dubbed DarkSat earlier this year, which featured a black anti-reflective coating. Recent ground observations of DarkSat in orbit have found it to be half as bright as a standard Starlink satellite, which is a good improvement, experts say, but still far from what astronomers say is necessary. Jeremy Tregloan-Reed, an astronomer from the University of Antofagasta on the observation team that evaluated the prototype, commented:

I wouldn’t consider DarkSat a victory but rather a good step in the right direction.

The team compared DarkSat to a typical Starlink sibling using a 0.6m telescope at the Ckoirama Observatory in Chile and found that although DarkSat’s anti-reflective coating makes it invisible to the naked eye, it remains far too bright to avoid interfering with the Vera C. Rubin Observatory – currently under construction in Chile – and other large telescopes. Additionally, DarkSat’s darker color retains too much heat, so the company is sticking with the visor alternative instead.

Astronomers hope to observe VisorSat and compare it with DarkSat once the observatories reopen after the Covid-19 shutdown. With SpaceX’s plans, plus Amazon’s Kuiper project, OneWeb, China Hongyan, and other projects launching their own global networks of hundreds or thousands of satellites with little or no regulation, the scale of the satellite constellation problem in astronomy may only increase.

A trail of several white dots moves across a starry sky.
A trail of Starlink satellites characterized by their dotted appearance moves across a starry sky. Image via Star walk.

Bottom line: Have you seen a bunch of bright satellites cross the night sky together? These are most likely SpaceX Starlink satellites, which create relatively bright, large, and moving mega-stellations. Starlink’s goal is to provide global broadband coverage for high-speed Internet access, especially for rural and remote areas. Astronomers and sky watchers are concerned about Starlink’s potential to interfere with their work of understanding the universe and their enjoyment of the night sky.


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