At the title screen, press Y, Y, X, X, A, A, B, B. If you've done the trick correctly, you'll hear a confirmation tone. To bring up the Select screen while playing, pause and press Y.
Make it so with this complete set of mission passwords.
BGTTBTBU Orientis Alpha IV Epidemic
CGTTBTBB Eunacian's Derelict Spacecraft
BDTTCTBV Trapped Miners on Orientis Gamma II
GCTTCTBV Trip to Codis Mu IV concerning the Tavad
JFTTCTBV Rescue captured Nakamoti Freighter
BKFTCTBB Collect mineral samples on Orientis Gamma III
LQTTCTBB Appearance of the IFD
LHTTMTBV Crystal Shard 1
MGTTMTBV Crystal Shard 2
NNTTHTBB Crystal Shard 3
PHTTNTBV The Final Test