NASA postpones spacewalk over 'debris' alert

NASA has postponed a spacewalk scheduled for Tuesday over a "debris notification" for the International Space Station. Two astronauts were set to venture outside the orbiting research laboratory to repair a failed antenna. 

Astronauts Thomas Marshburn and Kayla Barron were scheduled to exit the International Space Station's Quest airlock for a spacewalk that would focus on replacing an S-band Antenna Subassembly (SASA) with a spare, NASA said. It was set to be Marshburn's fifth spacewalk, and Barron's first.

The process was expected to take about six hours and 30 minutes. However, after receiving the debris notification, the spacewalk was postponed indefinitely.

"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," NASA said in a statement.

Earlier this month, NASA said the International Space Station and seven people on board were at increased risk from orbiting debris after a Russian anti-satellite missile test. 

Currently, four Americans, two Russians and one German astronautlive aboard the space station.

While NASA is yet to fully quantify hazards posed by more than 1,700 larger fragments that the space agency is tracking around the station's orbit, the 7% higher risk to spacewalkers falls "well within" fluctuations that have been seen in "the natural environment" in the past, according to Dana Weigel, NASA deputy manager of the International Space Station program.

However, NASA stopped short on Tuesday of directly connecting the canceled spacewalk to the incident. 

see/wmr (AP, Reuters)