Nasa calls off ISS spacewalk due to space debris threat

Astronauts Thomas Marshburn and Kayla Barron were due to scale the outside of the space station today in order to mend a faulty antenna.

The faulty S-band radio communications antenna assembly, now more than 20 years old, was to be replaced with a new spare stowed outside the space station.

However, Nasa issued a debris notification on Monday evening and the mission was called off.

“Due to the lack of opportunity to properly assess the risk it could pose to the astronauts, teams have decided to delay the spacewalk until more information is available,” the agency said.

“The space station schedule and operations are able to easily accommodate the delay of the spacewalk.”

It was not made clear how close debris had come to the ISS, which orbits approximately 402km above the Earth.

Debris is becoming an increasing problem for space operations. The amount of objects, their combined mass and their combined area has been steadily rising since the beginning of the space age, leading to the increased danger of involuntary collisions between operational payloads and space debris.

The ISS had to shift into a wider orbit earlier this month in order to avoid space junk from a Chinese satellite.

Just a week later, astronauts aboard the Space Station were forced to seek shelter in their docked capsules after Russia tested a space missile by destroying one of its satellites, an action that immediately cast fast-moving debris into orbit.

While the residual cloud from the destroyed satellite has now dispersed, Nasa calculates that remaining fragments continued to pose a “slightly elevated” background risk to the space station as a whole and a 7 per cent higher risk of spacewalkers’ suits being punctured, compared to the perceived level of risk before Russia’s missile test.

With well over 6,000 satellites already circling above the Earth, of which nearly 3,000 are defunct and classed as ‘space junk’, clean-up solutions represent a big business opportunity for organisations keen to tackle the space debris problem.

During the G7 Leaders’ Summit in June, delegates from the member countries collectively committed to the “safe and sustainable use of space” by going to greater lengths to tackle the problem of space debris.