He was pilot of the Atlantis space shuttle mission in February 2001 that delivered and connected the Destiny module to the International Space Station (ISS). Since 2002 he has been chief of NASA's CapCom (spacecraft communicator) Branch. Following the Columbia space shuttle disaster in 2003, Polansky flew aboard space shuttle Discovery as mission commander to the ISS. His last flight was in 2009, when he commanded space shuttle Endeavour to the ISS. Polansky also served as director of operations at the Gagarin Cosmonaut Training Center in Star City, Russia.

Polansky joined NASA as an aerospace engineer and research pilot in 1992, was selected as an astronaut in 1996, and retired from NASA in 2012. During his career, he logged more than 993 hours in space.