PARIS: It is still not clear what exactly fell onto a Kenyan village last month, but such events are likely to become increasingly common given the amount of space debris drifting above the planet.

What we know

A metallic ring of roughly 2.5 metres (8 feet) in diametre and weighing some 500 kilogrammes (1,100 pounds), crashed into Mukuku village, in Makueni county, in the south of the country on Dec 30.

The Kenya Space Agency (KSA) has opened an investigation and is examining the possibility that it might have been the separation ring from a rocket. Other theories have already surfaced however, and a KSA spokesman has said they have not ruled out anything.

The theories being examined

It is not even certain that what crashed in Kenya came from outer space. But for Romain Lucken who runs Aldoria, a French start-up that tracks debris in space, it is “absolutely plausible” that it did. He said he thought it might be part of the upper stage of a Polar Satellite Launch Vehicle (PSLV) developed by India’s space agency.

“There is a mission that was sent up on Dec 30 with a return date that fits well, and most of all, a point of re-entry that fits very well, to within a few dozen kilometres,” he said. Aldoria, which has 15 telescopes around the world, searches for information on launches and then works out flight paths based on “the typical trajectories of each of the main launch sites”. But Jonathan McDowell, an astronomer at the Harvard-Smithsonian Centre for Astrophysics, is not convinced.

It was McDowell who identified a piece of the International Space Station (ISS) that crashed down on a house in Florida last April. “I do not believe this object came from space. Maybe fell off an airplane,” he said. “Give me evidence it is space debris.” He has not however entirely ruled out that it is part of an Ariane 5 V184 launch in 2008 that finally returned to earth.

But the French aerospace group said: “This piece does not belong to an element from a European launcher operated by Arianespace.” John Crassidis at New York’s SUNY, which works with Nasa on space debris, endorsed the assessment released by the Kenya Space Agency.

“I think their technical assessments are 100 percent accurate, and they’re going to figure out what country it came from, because every country does things a little bit differently,” he said.

While it could be a separation ring from a rocket, as the KSA was considering, it might also have come from the upper stage of a rocket. “Those tend to be smaller,” he said.

Christophe Bonnal, a French specialist in space debris, said the debris might have come from a military launcher. “They are armoured, which fits with the fact that it is very big and heavy,” he said. But then it could also have come from a digger or a tank, he added.

Assessing the risk

So far, at least, such incidents have not caused any deaths, but since the number of space launches is rising, so too are the risks. “Ten years ago, an object that might create impact fragments re-entered the atmosphere every two weeks,” said Stijn Lemmens, a specialist in debris at the European Space Agency (ESA). “Now, that can happen twice a week.” For Lucken, at Aldoria, it is just a question of time.

Published in Dawn, January 9th, 2025