Seventeenth Columbia flight. The International Microgravity Laboratory-2 (ML-2) used furnaces and other facilities to produce a variety of material structures, from crystals to metal alloys. Over 80 investigations were studied as prepared by over 200 scientists from six space agencies. Landed July 23, 1994 at Kennedy Space Center, FL. Mission Duration: 353 hours 55 minutes. Iron-on. 4″ diameter.