   sts-39 was the twelfth mission of the space shuttle discovery. the primary purpose of the mission was to conduct a variety of payload experiments for the department of defense. ==crew==  ===crew seating arrangements=== {| class="wikitable" |- ! seat ! launch ! landing | rowspan="8" style="text-align: center;" | 225pxseats 1â4 are on the flight deck. seats 5â7 are on the middeck. |- ! s1 | coats | coats |- ! s2 | hammond | hammond |- ! s3 | harbaugh | bluford |- ! s4 | mcmonagle | mcmonagle |-
Space_Shuttle_missions Spacecraft_launched_in_1991