Leonard David's INSIDE OUTER SPACE

Image credit: LeoLabs/McKnight

Old hardware discarded in Earth orbit is haunting our future hopes for space sustainability.

That’s the word from space debris guru, Darren McKnight, senior technical fellow at LeoLabs, an organization that persistently monitors activity in space to reveal threats to safety and security.

In a September 1 communiqué on near hits of space hardware, McKnight notes that on May 29, a defunct U.S. Defense Meteorological Satellite Program (DMSP) spacecraft crossed paths with an abandoned rocket body from 1971, lofted by the former Soviet Union.

Illustration of a Defense Meteorological Satellite Program (DMSP) spacecraft.
Image credit: U.S. Air Force

“This conjunction was identified by me querying our LeoMap tool as to the conjunction over the last 90 days that involved the two oldest objects,” McKnight notes.

Live long and ponder

In a bit of historical context, the space debris specialist adds that the Soviet SL-8 rocket body was abandoned in 1971, when Richard Nixon was President of the United States.

“Since then, it has orbited the Earth about 290,000 times,” McKnight adds, “the distance traveled by this piece of hardware is greater than the distance from the Sun to Pluto and back.” This enormous distance traveled, he said, puts into perspective the collision risk posed by such long-lived objects deposited in cluttered orbits many decades ago.

The defunct DMSP satellite (called OPS 5644 when launched) was deployed in 1977 by then U.S. President Gerald Ford.

Image credit: Johan Swanepoel/Adobe Stock via RAND

Prolific breakup event

McKnight reports that if the two objects had collided center-of-mass on center-of-mass, it would have likely generated over 3,000 trackable fragments and another 30,000-plus lethal, yet uncatalogued fragments.

This amount of debris generation would have made it the second most prolific breakup event, McKnight points out, behind the 2007 Chinese anti-satellite test involving that country’s own Feng-yun 1C spacecraft.

Hot spot

“This region of low Earth orbit where hundreds of similarly old and massive objects have been abandoned is known as Cluster 775 and is considered one of the three major ‘hot spots’ for collisional risk in LEO, McKnight said.

Image credit: LeoLabs/McKnight

Eying the future, McKnight said he’s positive there are more stories to tell in LEO about the dynamic collision environment. “I think that I have infinite material to work with!”

Lack of adherence

In an earlier statement regarding abandoned rocket bodies, McKnight has an equally unnerving view of the situation.

“In the last 20 years, China has abandoned more rocket body mass in LEO that will not adhere to the 25-year rule than rest of the world combined,” McKnight said, a rule that recommends space operators re-enter their hardware within 25 years following the completion of their mission.

“This is not a part of the space race anyone should try to ‘win,’” McKnight said, “yet they are singling themselves out by their lack of adherence to basic space sustainability norms.”