Selected by NASA in January 1990, Walz is a veteran of three space flights, and has logged over 833 hours (34.5 days) in space. He served as a mission specialist on STS-51 (September 12-22, 1993), was the Orbiter flight engineer (MS-2) on STS-65 (July 8-23, 1994), and was a mission specialist on STS-79 (September 16-26, 1996).
On STS-51, the crew of five aboard Space Shuttle Discovery deployed the U.S. Advanced Communications Technology Satellite (ACTS), and the Shuttle Pallet Satellite (SPAS) with NASA and German scientific experiments aboard. Walz also participated in a 7-hour space walk (EVA) to evaluate tools for the Hubble Space Telescope servicing mission. Following 158 orbits of the Earth, the mission concluded with the first night landing at the Kennedy Space Center. Mission duration was 9 days, 22 hours, and 12 minutes.
On STS-65, the crew of seven aboard Space Shuttle Columbia flew the second International Microgravity Laboratory (IML-2) spacelab module. During the 15-day flight the crew conducted more than 80 experiments focusing on materials and life sciences research in microgravity. The mission completed 236 orbits of the Earth, traveling 6.1 million miles, setting a new flight duration record for the Shuttle program.
Most recently, on STS-79, the six member crew aboard the Shuttle Atlantis docked with the Russian MIR station, delivered food, water, U.S. scientific experiments and Russian equipment, and exchanged NASA long duration crewmembers - bringing John Blaha to Mir and returning Shannon Lucid to Earth. During this mission, the Atlantis/Mir complex set a record for docked mass in space. STS-79 was the first flight of the double Spacehab module, and landed at KSC after a highly successful flight of 10 days 3 hours and 13 minutes.
Deployed and retrieved Orfeus-SPAS. During the EVA conducted tests in support of the Hubble Space Telescope first servicing mission and future EVAs, including Space Station assembly and maintenance. First night landing at KSC. Payloads: Advanced Communication Technology Sat-ellite (ACTS)/Transfer Orbit Stage (TOS), Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer—Shuttle Pallet Satellite (ORFEUS-SPAS) with Remote IMAX Camera System (RICS), Limited Duration Space Environ-ment Candidate Materials Exposure (LDCE) (Beam Configuration C), Commercial Protein Crystal Growth (CPCG Block II), Chromosome and Plant Cell Division in Space (CHROMEX), High Resolution Shuttle Glow Spectroscopy-A (HRSGS-A), Auroral Photography Experiment-B (APE-B), Investigation into Polymer Membrane Processing (IPMP), Radiation Monitoring Equip-ment (RME-III), Air Force Maui Optical Site Cal-ibration Test (AMOS), IMAX In-Cabin Camera.
Tested tools and techniques for extravehicular activity.
Carried IML-2; microgravity, biology experiments. Payloads: International Microgravity Laboratory (IML) 2, Orbital Acceleration Research Experiment (OARE), Commercial Protein Crystal Growth (CPCG), Air Force Maui Optical Site (AMOS), Military Applications of Ship Tracks (MAST), Shuttle Amateur Radio Experiment (SAREX).
On September 19 Atlantis docked with the Russian Mir space station. Aboard Atlantis in the payload bay were the Orbiter Docking System, the modified Long Tunnel, and the Spacehab Double Module, containing supplies for the Mir. Astronaut John Blaha relieved Shannon Lucid as NASA resident on the complex. Atlantis undocked from the Mir complex on September 23 at 23:33 GMT. Valeriy Korzun, Aleksandr Kaleri and John Blaha remain on Mir. On September 26 Atlantis closed its payload bay doors, and at 11:06 GMT fired its OMS engines for a three minute long deorbit burn. After entry interface at 11:42 GMT the spaceship flew across Canada and the US for a landing at the Kennedy Space Center's Runway 15 at 12:13 GMT.