NASA engineers tracked the tool, and decided to use Discoverys thrusters on 14 March to boost the station four kilometers higher, to ensure the ISS would not collide with the piece of space debris. Transferring expedition crews By 14 March, the expedition crews had completed the change over, but until the shuttle undocked, Shepherd officially remained commander of the station. The morning of the 14th the astronauts' wake-up call was the song "Should I Stay or Should I Go" by The Clash, at the request of Shepherd's wife. Shepherd, a former Navy SEAL, said during the change over ceremony: "May the good will, spirit and sense of mission we had enjoyed on board endure. Sail her well." The commander of Discovery, Jim Wetherbee, said "For Captain Shepherd and his crew, we hold you in admiration as we prepare to bring you home. This has been an arduous duty for you. This ship was not built in a safe harbor. It was built on the high seas." Undocking and landing The crew's four and a half-month tour aboard the ISS officially ended on 18 March 2001, when Discovery undocked. The Expedition 1 crew returned home to Earth on STS-102, landing on 21 March 2001, on a rare night landing at 2:30 am local time. Two days after the landing, coincidentally, Mir was intentionally burned up during atmospheric reentry, ending its 15 years in orbit. Daily activities In a typical day, each crew member divided his time between physical exercise, station assembly and maintenance, experiments, communications with ground personnel, personal time, and bio-needs activities (such as rest and eating). The crew's daily schedule usually operated on UTC; for example, a typical morning had been scheduled to begin with an electronic wake-up tone at about 05:00 UTC. But during the expedition, a more typical wake-up time was actually between 06:00 and 07:00 UTC. The crew's sleep habits were sometimes shifted to accommodate the schedules of visiting shuttles or resupply vehicles. Following the wake-up call, the crew was given some time to clean up, have breakfast, and read e-mail which had been uplinked to them from flight controllers. Their work day included a lunch break at midday (UTC), and ended with a mid-afternoon planning session with flight controllers, regarding the next day's activities. Most days ended with some entertainment, with the crew watching all or part of a movie; this was thought to be