Short answers, pulled from the story.
When We Left Earth first aired on Discovery Channel on the 8th of June 2008, with new episodes airing on the following two Sundays and the series concluding on the 22nd of June. Each airing consisted of two hour-long episodes.
The miniseries consists of six episodes spanning American human spaceflight from the Mercury and Gemini programs through the Apollo Moon missions and the construction of the International Space Station.
The series was narrated by actor Gary Sinise, who played astronaut Ken Mattingly in the 1995 film Apollo 13. It was executive produced by Richard Dale and Bill Howard.
The miniseries was created to commemorate NASA's fiftieth anniversary in 2008. Discovery partnered with NASA in September 2007 to produce the series, and the broadcast was timed to coincide with the agency's anniversary.
The Discovery team reviewed 500 hours of archived film and selected 150 hours to be transferred to high definition. Discovery then donated the high-definition film back to NASA.
The score was composed by Richard Blair-Oliphant and conducted by Benjamin Wallfisch. The music and sound were nominated for a 2009 News and Documentary Emmy Award for Outstanding Individual Achievement in Music and Sound.