TAMPA, Fla. — New star-tracking sensors in the works would enable all manner of satellites to keep an eye out for hazardous orbital debris too small to detect from the ground.

Star trackers use the known position of stars to help keep satellites properly oriented and pointing in the right direction. 

Belgian spacecraft component specialist Arcsec is working with Portuguese space traffic management venture Neuraspace on a debris-spotting star tracker they expect to demo in space by 2025.

Adding data from Arcsec’s sensors to the pool of information Neuraspace gathers from public sources and partnerships with ground telescope providers would enable the Portuguese venture to track much smaller orbital debris, according to Neuraspace chief operating officer Chiara Manfletti.

Meanwhile, Jacksonville, Florida-based Redwire has developed a star tracker it says can be used to detect debris, slated to be on orbit in the next three to six months after entering production this summer.

Other manufacturers are also looking into developing star trackers that satellite operators could use for debris detection alongside attitude and orbit control.

More tools for debris hunters

Denver-based, national security-focused satellite maker True Anomaly announced plans in August to use Redwire SpectraTRAC star trackers and cameras, which would work in concert for spacecraft dedicated to chasing, and imaging, uncooperative objects up close.

Redwire senior vice president Don Wesson declined to disclose other customers for SpectraTRAC, but said the object detection feature enables space domain awareness applications including debris detection, rendezvous and proximity operations, and space situational awareness.

Customers can opt for the object detection feature at time of purchase or anytime in the future, he said, even during their mission and without being paired up with a Redwire camera.

While Arcsec CEO Tjorven Delabie said enabling debris-monitoring on Arcsec star trackers already in orbit could be done with a software upgrade from the ground, he said the company is still figuring out how best to reallocate the star tracker’s internal computing power to accommodate this capability.

The Belgian company’s work to upgrade star trackers follows a recent 1.3 million euro ($1.4 million) grant from the European Innovation Council.

Converting trackers

Star trackers Arcsec and others provide can already pick up non-celestial objects passing through their field of view, but this data is often discarded to conserve onboard computational power.

Luis Gomes, CEO of small satellite specialist AAC Clyde Space, said operational constraints are one of the main reasons his company has not sought to add the capability to its star trackers.

Most star trackers operated for attitude control do not generate imagery on a routine basis, Gomes said, and operators only run them in that mode when things go wrong because it is labor-intensive.

“I suppose it would be possible to change the algorithms on [star tracker] processors to also detect debris,” he said, “but that is not the first thing I would consider doing with our limited computational resources.”

Arcsecc would need to convince star tracker customers who do not track debris as part of their main mission to feed this data into Neuraspace’s platform — either through new orders or by retrofitting satellites already in orbit via software upgrades. 

Arcsec has delivered 50 star trackers since its founding in 2020, mostly to commercial cubesats up to 150 kilograms in low Earth orbit (LEO), and two have been launched to space so far.

“It’s a very small cost for them” to add the debris-tracking capability to their star tracker, Delabie said, “but it is a bit of a cost in terms of data budget.”

He said Arcsecc is looking into various incentives, including compensating star tracker customers for collecting and sharing debris data with Neuraspace.

Giving a satellite a debris-monitoring role would improve the operator’s brand image, he added.

Arcsec’s partnership with the Portuguese venture provides another way to convert star tracker users into debris watchdogs.

“If one of our customers were to have Arcsec sensors onboard, then they would get a better service,” Neuraspace’s Manfletti said, because insights would come from their own sensors and not just the broader network.

A Neuraspace customer with a compatible star tracker would get better conjunction analysis and maneuver suggestions from the space traffic management platform. 

Neuraspace recently announced it is serving customers that collectively control more than 250 satellites in orbit, including one operated by Earth observation provider Dragonfly Aerospace.

In addition to commercial satellite operators, Neuraspace is seeking to sign up satellite manufacturers, subsystem providers, insurance carriers, regulators, and policymakers to its platform.

Improving accuracy

Because star trackers are typically optimized to detect bright stars, their ability to detect dark debris particulates is limited. 

Under perfect conditions, Arcsec’s star trackers should be able to pick up debris in LEO down to three centimeters depending on its reflectivity, Delabie said, while currently available systems are only able to catalog objects down to around 10 centimeters accurately.

Redwire’s Wesson said SpectraTRAC’s object-detection capabilities are also dependent on the brightness of the reflected object — influenced by its size, shape, and distance — and would perform in a similar manner to Arcsec star trackers under ideal conditions. 

Even a tiny piece of space debris poses a threat to space missions and assets.

In 2016, The European Space Agency said a particle a few millimeters size hit one of two 10-meter-long solar panels on its Copernicus Sentinel-1A Earth observation satellite, damaging an area 40 centimeters in diameter and causing a small, albeit manageable loss of power.

A collision with a similar-sized particle can be a life-ending event for smaller cubesats. 

Although manufacturers such as SpaceX are working to make their satellites less reflective to reduce light pollution, Delabie said he expects these efforts will continue to focus on surfaces facing Earth, and not all the angles Arcsec sensors would view.

Even more rudimentary observations would improve orbit calculations for improving space safety, according to Arcsec and Neuraspace, as ventures including NorthStar, Vyoma, and Digantara plot dedicated constellations with better sensors to track debris.

Leveraging equipment operators are already taking with them to space also promises a faster way to add debris-tracking data nodes into the mix.

Jason Rainbow writes about satellite telecom, space finance and commercial markets for SpaceNews. He has spent more than a decade covering the global space industry as a business journalist. Previously, he was Group Editor-in-Chief for Finance Information...