28 February 2017
A Silicon Valley spin-out that is tracking space debris with the aim of preventing collisions in low-Earth orbit switched on its second phased-array radar in February in Texas. The new site, 80 miles west of Midland, took six months to construct and will add to data LeoLabs is already collecting from a radar in Alaska. A second radar facility brings LeoLabs’ coverage of known low-Earth objects to 95% – monitoring approximately 13,000 objects on a 24/7 basis with multiple observations per day in all weathers – says chief executive Dan Ceperley. However, he is aiming for 100% and is already scouting for additional sites in Northern and Southern latitudes as well as equatorial areas. The next phase of expansion will see 250,000 objects monitored, he says.
There is growing awareness that collision risks are rising with the new space economy as the number of satellite launches ramps up to realise plans for mega constellations – making the space around our planet ever more congested. LeoLabs wants to be the first private company to offer collision avoidance and initial orbit determination services and is working fast to build a global network of radar sites to map objects in LEO. Target customers are commercial satellite operators in LEO, satellite management firms and government agencies. Although no specific customers have been announced, Ceperley says “customer engagements are underway”.
The radar technology used by LeoLabs was developed at California research institute SRI International to investigate the Earth’s ionosphere. LeoLabs was spun-out in 2016 and in February 2017 closed a $4m investment round backed by SRI, Japanese investment fund Horizons Ventures and Airbus Ventures.
The US Air Force’s Space Surveillance Network – a worldwide network of 30 optical and radar sensors including space based sensors – catalogues and tracks about 23,000 space debris objects larger than 5-10cm in LEO and 30cm-1 metre in 36,000km geostationary orbits. On a routine basis, its Joint Space Operations Center (JspOC) at Vandenberg Airforce base in California – conducts conjunction analysis for all active spacecraft.
In Darmstadt, Germany, the European Space Agency’s Space Debris Office offers conjunction predictions and estimates of collision risks to missions flown by ESA and other agencies. Models estimates there are more than 750,000 debris object larger than 1cm in Earth orbit. NASA puts the figure at more than 22,000 pieces of space debris more than 10cm wide and hundreds of thousands of marble-sized pieces orbiting the world. At typical collision speeds of 10km/sec in low orbits, impacts by millimetre-sized objects could cause local damage or disable a subsystem on an operating satellite; collisions with debris larger than 1cm could disable an operational satellite and impacts by debris larger than 10cms could lead to a catastrophic break-up, says ESA.
The majority (about 58%) of the catalogued objects originate from more than 290 break-ups in orbit, mainly caused by explosions, and from about 10 suspected collisions (of which four are confirmed between catalogue objects). On average, the agency executes 12 collision avoidance manoeuvres a year on average. NASA reports that the International Space Station (ISS) had performed more than 15 avoidance manoeuvres by the end of 2012.
Figures from ESA further illustrate the scale of the problem: since Sputnik, more than 5,200 launches have orbited some 7,500 satellites – 4,300 are still in orbit but only about 1,200 are operational. The remaining hundreds of thousands of objects in orbit are debris – everything from used rocket bodies and tools lost by space-walking astronauts to fragments.
Most of the catalogued orbiting objects, says ESA, are fragments from some 290 explosions – four or five per year, historically, often of spacecraft fuel tanks. Others stem from fewer than 10 known in-orbit collisions. Some 3,300 pieces resulted from a Chinese anti-satellite missile test in 2007.
According to ESA, simulations point to collisions overtaking explosions as the dominant cause of in-orbit break-ups within a few decades, at least in orbits around 800-1400km altitude – too high for atmospheric drag to clear debris, and popular with Earth observation and scientific missions. This, even in the obviously unrealistic event of there being no further launches, which number around 100 annually today. A runaway collision cascading scenario – deemed “most probable” by ESA, and called the Kessler Syndrome after Don Kessler of NASA, who described it in 1978 – would see fragments collide with large, intact objects, creating more fragments and further collisions.
Ceperley was a program director at SRI where he developed SRI’s commercial satellite tracking business. He has a PhD in electrical engineering and computer science from UC Berkeley. Fellow LeoLab co-founders Michael Nicolls – with a PhD in electrical and computer engineering from Cornell University – and John Buonocore – a radio electronics designer with more than 30 years experience – also work with former NASA astronaut and Google program manager Edward Lu, an astrophysics PhD who founded the B612 Foundation for the protection of Earth from asteroid impacts. LeoLabs other executive, Alan DeClerck, has an M.Phil in international relations from Oxford and an MBA from Stanford.