• Annemijn Witkam

The legal challenges in the battle for the sky - part 1

Commercial telecommunication satellites and astronomers are engaged in a battle for the sky; the former is sullying the skies whereas the latter relies on unsullied skies for their observations. If no action is taken, astronomers will lose out and our skies will be littered with satellites.

Recently, the US Federal Communications Commission (FCC), responsible for regulation of communications law and technical innovation, authorized several commercial satellite projects, including SpaceX’s project Starlink to distribute broadband satellite services. In May 2019, the first cluster of sixty Starlink satellites was launched into a 430 km circular earth orbit.[1] Part 1 of this blog explains how Starlink works and its impact on science. Part 2 focuses on the challenges commercial satellites like Starlink create for space law.

Starlink - a disruptive business technology

The SpaceX Starlink satellites systematically collaborate to provide end users with high-speed internet. SpaceX intends to provide the public with a consistent global coverage, by creating a network of thousands of satellites moving around the earth in Low Earth Orbit (LEO). LEO can be further divided into Lower and Upper LEO; Starlink satellites move in the range of Lower LEO.[2] Estimations of McDowell, astronomer at Harvard-Smithsonian Center for Astrophysics, show that Starlink is responsible for a substantial number of so-called Big satellites (> 100 kg) in Lower LEO.[1]

To prevent space pollution, the Inter-Agency Debris Committee recommends objects in LEO be removed after a maximum of 25 years. As such, Starlink satellites are made of self-destructing material, thus vanishing upon reentry into the atmosphere, thereby cleaning up their own debris and keeping the skies uncluttered.[1]

Besides leaving little to no debris, Starlink satellites ensure a consistent global internet connection which is faster and stronger in data transmission than any other current internet provider and is, therefore, an attractive alternative, especially for financial markets and high-frequency traders. For applications used within these markets, Starlink’s high-speed internet is valuable.[3] Another advantage of satellites instead of the currently-used terrestrial cellular towers is that they create a global connection.[4]


Clearly, Starlink compared to other internet providers, offers users benefits. There are, however, also concerns; concerns related to the visibility of Starlink satellites and to the emission of radio signals, both of which impact science.

First of all, due to the combined effect of quantity, size and position of Starlink satellites, they have a high visibility, hindering astronomical observations.[1] This high visibility is, however, challenged by Elon Musk, CEO of SpaceX, who argues that “there are already 4,900 satellites in orbit ... Starlink won’t be seen by anyone unless looking very carefully and will have ∼ 0% impact on advancements in astronomy.” A claim that McDowell says is inaccurate. He asserts that Starlink is responsible for a large number of Big satellites in Lower Leo, an area in space in which satellites are visible to the naked-eye.[1] If no action is taken, Starlink satellites will soon dominate the population of objects that can be seen with the naked-eye. FCC has already authorized SpaceX’s plans to ultimately launch 12,000 or maybe even 30,000 Starlink satellites into Lower LEO. This would greatly impact astronomical observations.

Another cause of visibility of Starlink satellites is their brightness.[1] The surface of the satellite is covered with a highly reflective metal. As a result, these satellites are visible in the hours before sunrise and after sunset. This visibility was confirmed by SeeSat, a satellite observing group, immediately following Starlink’s first launch. SpaceX responded to this by providing the satellites launched into Lower LEO in January 2020, with a special brightness-reducing coating. Unfortunately, the result was disappointing. Researchers at Cornell University confirmed that these satellites were still extremely bright and thus formed a disturbance for scientific telescopic observations and to the natural darkness of the sky.[5]

Finally, radio signals emitted by Starlink satellites also form a problem as they jeopardize astronomical observations. According to the International Astronomical Union (IAU), this is because Starlink radio signals interfere with the astronomers’ radio signals. The gravity of this disturbance becomes clear when one realizes that astronomers were only successful in capturing an image of a black hole due to a sky free of any radio signal interference. Any other such observations also depend on signal free skies.

In short, Starlink satellites negatively impact science, through the disturbance of astronomical observations. The question thus arises as to whether scientific interests were assessed and taken into consideration in the authorization process of Starlink. Part 2 of the legal challenges of the battle for the sky will further analyse this.

[1] J.C. McDowell, ‘The Low Earth Orbit Satellite Population and Impacts of the SpaceX Starlink Constellation’ , ApJL Harvard March 18 2020.

[2] J.C. McDowell, ‘The edge of space: Revisiting the Karman Line’, Acta Astronautica, 151 2018, p. 668.

[3] D. Heaven, ‘Elon Musk's space internet’, New Scientist, 10 November 2018, p. 5.

[4] A. Sayin, M. Cherniakov & M. Antoniou, Passive radar using Starlink transmissions: A theoretical study, EasyChair Department of Electronic, Electrical and Systems Engineering, University of Birmingham: Birmingham 14 April 2019.

[5] J. Tregloan-Reed et al, First observations and magnitude measurement of SpaceX’s Darksat, Cornell University, 17 March 2020.