Extreme space debris collision could leave wreckage in orbit for tens of thousands of years, Pentagon warns

Space debris as large as a car nearly collides every month at 15 kilometres per second

(ESA)

Space debris around the planet is so bad that there would still be a “formidable problem” even if international guidelines were set and made legally binding, according to a new Pentagon report.

There are currently around 25,000 objects of space debris larger than 10 centimetres in size orbiting the planet, and between 600,000 and 900,000 pieces of non-trackable debris that could pose a risk to spacecraft and satellites.

“The probability of collision between massive derelict objects in [low-Earth orbit] is rising and almost certainly will continue to rise until at least 2030 as a result of fragmentation events such as collisions or battery explosions, [anti-satellite weapon] testing, and a rapidly increasing number of space launches worldwide”, the Defense Intelligence Agency states.

“Prior to 2007, most debris came from explosions of upper stages of SLVs [Satellite Launch Vehicles]. Today, nearly one-half of all cataloged debris are fragments from three major events: China’s destruction of its own defunct weather satellite in 2007, the accidental collision between a US communications satellite and a dead Russian satellite in 2009, and the 2021 Russian Nudol ASAT test.”

There are also approximately 1,300 pieces of debris larger than a car, and these objects pass each other at a close distance dangerously often. Some pass within one kilometre of each other monthly, the report states, at a speed of between 10 to 15 kilometres per second.

“A collision between these objects almost certainly would create 3,500–15,000 cataloged fragments”, the report continues, and between 55,000 to 225,000 pieces that cannot be tracked. Typically, a satellite breakup creates about 250 pieces of catalogued debris.

The odds of a collision of such these massive objects 1,500 kilometres above the planet is in one in 5,000, while for those 850 kilometres in altitude it is one in 800.

“Although the debris contribution for a collision at 850 kilometers would … generate ~15,000 trackable fragments”, the report states, “the debris from a collision at 1,500 kilometers would remain in orbit potentially for thousands of years”.

It adds that “as the altitude gets closer to 1,500 kilometers, derelicts and debris can remain for more than 10,000 years” and that “a collision of two objects at 975 kilometers—the most likely of the collision probabilities at about 1 in 120 chance per year—would leave many fragments in orbit for more than a thousand years.”

Although space debris guidelines were set in 1993 and adopted by the United Nations, countries have generally ignored the responsibility we have to keep the planet free from debris.

An infamous study by Nasa scientist Donald Kessler in 1978 warned that, if two large objects collided, the domino effect caused by the material breaking apart, colliding into other material, and breaking again, could create an impenetrable layer of debris that would make terrestrial space launches impossible.

“Even if international and national guidelines were made legally binding, mitigation thresholds were made more stringent, or if compliance were even close to 100 percent; there would still be a formidable debris problem from the remnants of the first 63 years of space operations”, the report concludes.