Space adverts are now economically viable but potentially dangerous

Falling launch costs for satellites mean space advertising may now make commercial sense, according to a feasibility study, but the idea remains controversial

By Alex Wilkins

Launching satellites into orbit is cheaper than ever

Jacques Dayan/Shutterstock

Constellations of satellites that reflect sunlight to Earth could be used for space advertising at a commercially viable cost of $65 million per mission, according to a feasibility study. But the idea is controversial among researchers, who warn of a pile-up of dangerous space debris and light pollution for ground and space-based telescopes.

Previous proposals for space advertising didn’t make commercial sense – the cost of launching enough satellites, which tend to remain in the correct orbit for only a short amount of time, has been prohibitive for any serious attempts.

But as launch costs have decreased with the advent of private space companies, Shamil Biktimirov at the Skolkovo Institute of Science and Technology in Moscow, Russia, and his colleagues think it could now be viable if the mechanics of how the satellites are used as advertising are reassessed.

To do this, they borrowed techniques that describe the dynamics of mega-constellations, such as that of Starlink’s communications satellite fleet, and used this to calculate how much revenue companies could get for keeping their satellites in the sky for certain lengths of time.

They propose that a fleet of about 50 satellites equipped with curved reflectors could orbit around the line where day turns to night and reflect the sun’s light to a patch of ground below. They would be arranged to form an image made of bright pixels showing a logo or a basic image. Viewers on the ground would see the constellation move across the sky in around 10 minutes around dawn or dusk, growing from half-moon size to two to three times bigger than the moon at its peak.

To maximise revenue, the satellites would change formation around 25 times to target different locations in a three month period of operation before the satellites run out of fuel and slowly descend towards Earth and – Biktimirov hopes – burn up.

But this long descent could be a problem. “The spaceflight risk from debris related to these objects is considerable,” says John Barentine of Dark Sky Consulting, a company based in Tucson, Arizona. “Left derelict in orbits with long lifetimes, every single object becomes a potential ‘bullet’ that threatens every other object in similar orbits. Any one might set off a catastrophic cascade of debris generation.”

Biktimirov and his team say the descent of the satellites and any potential collisions could be monitored, but some are sceptical of how accurately this could be done. “The debris is especially concerning, given that tracking objects and satellites across a range of sizes and orbital parameters is inherently challenging and is affected by many factors including solar storms,” says Aparna Venkatesan at the University of San Francisco, California.

The only way to really mitigate this risk is by taking the satellites down as soon as they stop functioning, says John Crassidis at the University of Buffalo in New York. “Until there is a mandate to immediately remove the satellites once their formation is no longer maintained, then they will be a problem,” he says.

As well as the risk from debris, the reflected light could interfere with important telescopes, both on Earth and in space, including asteroid monitoring systems. “Astronomy already contends with the interference from the thousands of satellites already in orbit and faces a future in which that number may be as much as 100 times higher than it is now within a decade. Space advertising will only make this worse,” says Barentine.

Journal reference: Aerospace, DOI: 10.3390/aerospace9080419

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