A mysterious spacecraft plummets to Earth in Pennsylvania. Is it an undisclosed Soviet probe or a greater threat lurking? Meanwhile, NASA makes an astonishing discovery on Mercury: ice. In another twist, an enigmatic entity casts a towering shadow on Phobos, Mars's largest moon. What could this phenomenon signify?
Show
NASA's Unexplained Files
Episode
S02E01
Air Date
Mar 02, 2015