Michelle Park
- May 7, 2021
- 4 min read

Starlink: A Threat to Stargazing

Today, I would like to share about Starlink satellites and their possible dangers. I first learned about this topic when I was taking photos using the Slooh telescopes and captured some satellite trails that unexpectedly ruined the view of my image:

(Image from Michelle Park using the Slooh telescopes)

As these bright satellite trails have become more frequent in astrophotography and in our night sky, I wanted to discuss about the implications of Starlink, which is a new satellite system that could jeopardize our heritage with the night sky.

What is Starlink?

Starlink is a satellite network system created by SpaceX to provide internet to individuals across the globe, especially in remote areas.

After development began in 2015, around 1600 of these satellites have already been launched. In fact, 60 more were launched 3 days ago! It is expected that this $10 billion project will result in the launch of more than 42,000 satellites.

How does Starlink ruin stargazing?

When Starlink was first launched, astronomers were shocked at how bright these satellites are. As more and more satellites have launched, satellite trails have become the norm rather than the exception in astrophotography today.

Some softwares are available to remove satellite trails, but these can be ineffective and costly - making them inadequate for new astrophotographers and professionals.

As one company soon gains dominance over our night sky, our view of the night sky is jeopardized with these bothersome satellite streaks.

How does Starlink ruin astronomy data collection?

For ground-based telescopes, maintaining the visibility of the night sky is everything. As SpaceX releases more of these Starlink satellites, no part of the world is safe from satellite streaks. Unlike issues like bad weather or air pollution that can be responded to by placing telescopes in different locations, Starlink satellite streaks cannot be avoided.

This image shows how data collection has been a challenge for astronomers after these Starlink"megaconstellations" block out the view of scientifically valuable regions of the night sky. (Image from CTIO/NOIRLab)

Ground-based telescopes are crucial for astronomy due to their low cost, greater access, easier maintenance, longer lifespan, less risk due to space junk, and ease of construction. For instance, the ground-based Giant Magellan Telescope was more quickly constructed with a price tag of $1 billion in contrast to the $10 billion space-based James Webb Space Telescope. Their ease of accessibility on the ground means that they can be more quickly updated with the newest technology and can be easily fixed.

However, these ground-based telescopes are now at risk. For example, the Vera Rubin observatory (a future ground-based observatory that will complete a large scale survey of the universe) will be impeded by Starlink. A simulation done by executives in charge of the telescope showed that 30-40% of the images photographed will have at least one Starlink satellite trail present. This growing congestion of satellites in data may mean that ground-based telescopes could become inefficient or even unusable in the following years.

How about DarkSat?

In response to growing criticism, SpaceX released DarkSats, a Starlink satellite that is a darker color. However, this was not as effective as expected. DarkSats only reduces half of the satellite's visible brightness, meaning that satellite trails still remain. In addition, the dark color means that the Starlink absorbs more energy and becomes hotter, resulting in it actually becoming brighter in infrared wavelengths!

In this image, the second line shows a DarkSat's satellite trail, which is still bright in the night sky and a hassle for astronomers to remove. (Image from Tesmanian)

The new solution by SpaceX is now VisorSats, which includes a visor on the Starlink satellite to shade it from sunlight and thus makes it invisible in the radio frequencies. Even though all Starlinks produced from now on will have the distinct visor, studies show that these are only 31% as bright as regular Starlinks - making them more effective than DarkSats but still giving the distinct satellite trails that hurt our view of the night sky.

The image above shows how VisorSats work to reduce the satellite's brightness, but scientists are still unsure how effective it will be. (Image from SpaceX).

Lack of a Solution

Despite this pressing issue, little to no action has been done to implement any safeguard in the Starlinks from damaging our view of the night sky. 12,000 Starlink satellites have already been approved by the US Federal Communications Commission (FCC) and SpaceX has been looking to approve around 40,000 more. In fact, the FCC has also approved a new Starlink altitude at under 570 km (versus their current height above 1100 km), which will only make these satellites bigger and brighter from Earth.

In June of 2019, the International Astronomical Union expressed their concerns regarding the Starlink satellite trails and called for regulations to control aspects of Starlinks that are hazardous to astronomy. The National Radio Astronomy Observatory (NRAO) has also been in discussions with SpaceX but no solutions have been agreed upon.

Although DarkSats and VisorSats have been achieved in a few satellites, most Starlinks launched already do not implement any safeguard against satellite streaks. As the FCC continues to approve new features and benefits for Starlink that imperil our view of the night sky, we are running out of time to find a vital solution.

What can you do?

Spread awareness about this issue to others - having more people know about this issue can encourage large-scale change!
Sign petitions and send them to friends or family (Here's a great place to start!)
Keep your eyes out for more news on Starlink in the future. We can only hope that new regulations will be passed to prevent satellite trails.