NASA astronauts Suni Williams and Butch Wilmore to swab the outside of the International Space Station for microorganisms

Astronauts Butch Wilmore and Suni Williams will conduct a spacewalk outside the International Space Station to swab the orbiting lab for evidence of microorganisms.

​ Astronauts Butch Wilmore and Suni Williams will conduct a spacewalk outside the International Space Station to swab the orbiting lab for evidence of microorganisms. Read More Breaking News, Latest News and Videos | CNN