We have an exclusive clip from the upcoming Discovery Channel mini-series, When We Left Earth: The NASA Missions, which premieres on the network on June 8 at 9 PM ET. Click below to get a little glimpse inside this mini-series, which is narrated by Gary Sinise.

Narrated by award-winning actor Gary Sinise, When We Left Earth: The NASA Missions is the incredible story of humankind's greatest adventure, as it happened, told by the people who were there. From the early quest of the Mercury program to put a man in space, to the historic moon landings, through the Soyuz link-up and the first un-tethered space walk by Bruce McCandless, this is how the space age came of age.