NASA astronaut Stephen K. Robinson anchored to the International Space Station's robotic arm during a spacewalk in August 2005.
NASA delayed a spacewalk set for Tuesday to replace a faulty communications antenna on the International Space Station after the agency received a "debris notification" for the station.
Why it matters: NASA did not disclose the origin of the debris, but the delay comes roughly two weeks after Russia intercepted a defunct satellite with a missile as part of a test that generated thousands of pieces of debris and forced the seven astronauts and cosmonauts aboard the ISS to take shelter.
- Debris in Earth's orbit is a major threat to satellites and people in space because both the junk and spacecraft are traveling at extremely high speeds.
The big picture: NASA astronauts Thomas Marshburn and Kayla Barron were set to exit the ISS at 7:10 a.m. EST on Tuesday to replace an antenna system that helps the station speak with flight controllers back on Earth.
- NASA said in a blog post Tuesday morning that it delayed the walk after the debris threat notification "[d]ue to the lack of opportunity to properly assess the risk it could pose to the astronauts."
- NASA said the station's communication operations can continue despite the delay.
Of note: The Air Force has attempted to simulate the impact of debris against spacecraft. In one test at Arnold Air Force Base, a 1-inch steel sphere traveling 19,1oo feet per second was able to tear a hole through a 4-inch aluminum plate.
- The ISS has been hit by debris before. Earlier this year, a piece of junk punched a small hole through one of its robotic arms operated by the Canadian Space Agency, though the damage did not affect its performance.
Go deeper: Russian anti-satellite test reveals dangers of space junk