Since the 1960s, when NASA astronauts first left the confines of Earth to begin exploration above and beyond our planet, their cameras have captured some amazing sights.
Some of those moments will be revealed Tuesday night on the Science Channel's "NASA's Unexplained Files," the final episode of its month-long "Are We Alone?" series.
Spanning the Mercury, Gemini, Apollo, Skylab and space shuttle programs, astronauts saw unusual lights and objects, some considered unidentified flying objects or UFOs.
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