Long-term human stay in space continues with Space Shuttle Mission STS-79, the fourth docking between the U.S. Shuttle and the Russian Space Station Mir. Astronaut Shannon Lucid will return to Earth with the STS-79 crew after a stay on Mir that began March 24. Succeeding her aboard the station will be fellow astronaut John Blaha, who flies up with the STS-79 astronauts.
If the mission timeline proceeds as scheduled, Lucid will have spent more than 180 days in space from launch to landing, establishing a new record for U.S. human stay in space.
The docking also allows for the transfer to and from Mir of thousands of pounds of logistical equipment, experiment samples and supplies, most of it located in the SPACEHAB Double Module in Atlantis’ payload bay.
Atlantis will lift off from Launch Pad 39A at a 51.6-degree inclination to the equator, which is the same as that of the Mir Space Station. The initial altitude will be 184 statute miles (296 kilometers), followed by a rendezvous orbit of about 245 miles (394 kilometers). As with all the Shuttle-Mir dockings, the launch window is brief — five to 10 minutes — to insure adequate propellant for the flight.
The approximately nine-day mission is scheduled to conclude with a landing at KSC’s Shuttle Landing Facility. STS-79 marks the 17th flight of Atlantis (OV-104) and the 79th flight of the Shuttle program.
Leading the veteran U.S. Shuttle crew is Mission Commander William F. Readdy (Capt., U.S. Naval Reserve), embarking on his third space flight. He also completed an assignment as NASA director of operations at the cosmonaut training facility in Star City, Russia, where U.S. astronauts prepare for stays on Mir. Pilot Terrence W. Wilcutt (Lt. Col., USMC) has flown in space once before, on STS-68 in 1994.
There are four mission specialists (MS). On the trip up, they are MS 1 Jay Apt (Ph.D.); MS 2 Tom Akers (Lt. Col., USAF); MS 3 Carl E. Walz (Lt. Col., USAF); and MS 4 John E. Blaha (Col., USAF, ret.). Both Apt and Akers have flown in space three times before, while Walz will be taking his third trip. As the MS 2, Akers also will serve as the flight engineer, supporting the commander and pilot.
Blaha is embarking on his fifth spaceflight. On previous missions, he served as either commander or pilot; he takes the mission specialist slot on STS-79 for the transfer to Mir. Lucid will take his place as MS 4 for the return trip. Blaha remains on the station until STS-81 in January 1997, when Jerry Linenger will arrive to succeed him. Following Linenger in May of 1997 will be Michael Foale, who will fly up with the crew of Mission STS-84.
Lucid’s crew mates for most of her stay on Mir have been the Mir 21 crew, led by Commander Yuri Onufrienko and Flight Engineer Yuri Usachev. In August, the Mir 22 crew of Commander Valery Korzun, Flight Engineer Alexander Kaleri and Cosmonaut-Researcher Claudi Andre-Deshays of the French Space Agency, arrived to replace the two Mir 21 cosmonauts.
Atlantis will catch up with Mir on flight day 3. The approach to the station is the same as that employed for earlier dockings, along the R-bar or radius vector, but the configuration of Mir has changed. A new module has been attached to the station called Priroda, which means “Nature.” Also new on the station is a cooperative U.S -Russian solar array that was attached during a recent extravehicular activity.
The addition of Priroda changes Mir’s weight and its mass distribution. The different mass properties required mission planners to change the orbiter thruster jet firing sequences needed to maintain the proper orientation of the mated spacecraft.
The new solar array will extend down the nose of the orbiter on the left side, but there will be adequate clearance between the two. During rendezvous and docking, the crew will make sure that the thruster jet firings are not jarring the array, particularly during the final approach.
Experiments, sample storage hardware and logistics are stowed in both the middeck of the orbiter and the SPACEHAB Double Module. Altogether 5,200 pounds (2,359 kilograms) of gear will be transferred to and from Mir, including water generated by the orbiter fuel cells.
The Orbiter Docking System (ODS) is located in the forward area of Atlantis’ payload bay. Atop the ODS is the Androgynous Peripheral Docking System (APDS), the Russian-designed mechanism that actually latches the two spacecraft together. The ODS also serves as a passageway through which crew members can pass.
Located aft of the ODS is the SPACEHAB Double Module. SPACEHAB modules have been flying on the Shuttle since 1993. The pressurized mini-research laboratory is providing an additional function for the dockings, offering much needed storage space in the payload bay. This is the second time a SPACEHAB is being flown in support of a Shuttle-Mir docking and the first flight of a Double Module.
Because the orbiter offers more room than Russian transport spacecraft, the Shuttle-Mir dockings have helped breathe new life into the 10-year-old Mir. For example, Atlantis will come back with a complete Orlon extravehicular spacesuit which could not fit into the Russian Soyuz transporter. Since the Shuttle-Mir dockings have begun, more than 10,000 pounds (4,536 kilograms) of logistics and hardware have been transferred to and from Mir via the Shuttle.
Included in the SPACEHAB experiment complement that remains on the Shuttle are:
Mechanics of Granular Materials (MGM), an experiment designed to evaluate the behavior of cohesionless granular materials in the dry and saturated states at low confining pressures;
Active Rack Isolation System (ARIS), a specially designed rack for holding microgravity research experiments. ARIS employs a sophisticated control system that dampens vibration disturbances which could impede the experiments. It could find use aboard the International Space Station if the design proves successful;
Extreme Temperature Translation Furnace (ETTF) for investigating gravitational influences on multiple types of materials and material processing techniques. The furnace will operate at about 300 degrees Kelvin higher (3,000 degrees Fahrenheit/1,649 degrees Centigrade) than any furnace previously flown in orbit. Investigators are particularly interested in studying superconducting materials, including ceramic and metallic components that are difficult to mix homogeneously on Earth.
The Thermo-Electric Holding Module (TEHM), located in the middeck, is a refrigerator/freezer which will be activated on-orbit and used to hold biological samples collected by Lucid during her stay aboard Mir. Samples and hardware also will be stored in the middeck of the orbiter. A similar piece of hardware, the Enhanced Orbiter Refrigerator/Freezer (EOR/F), is located in the SPACEHAB.
Other activities planned on-orbit include an ongoing series of investigations called Risk Mitigation Experiments, which take advantage of the Shuttle-Mir linkups to gather data about the environment in which the International Space Station will be operating. One RME will feature collection of data on the internal and external radio interference in the 400 mHz to 18 gHz frequency band. Radio interference is of increasing concern due to new ground-based communications and radar application transmitters.
Atlantis will separate from Mir on flight day eight, after five days of mated operations.
Atlantis’ most recent mission, STS-76, concluded with a landing at Edwards Air Force Base, Calif., on March 31. The orbiter was returned to KSC atop the Shuttle Carrier Aircraft on April 12 and towed to the Orbiter Processing Facility the following day to begin post-flight servicing and preparations for STS-79. Rollover to the Vehicle Assembly Building (VAB) occurred on June 24. A week later, on July 1, the fully assembled Shuttle was transported to Launch Pad 39A. The SPACEHAB was installed in the orbiter July 9 at the pad, and liftoff was scheduled for July 31.
The threat posed by Hurricane Bertha prompted the rollback of Atlantis to the Vehicle Assembly Building on July 10. Managers then opted to keep the Shuttle in the VAB to switch out the STS-79 redesigned solid rocket motors (RSRMs) with ones slated to fly on STS-80. The decision followed post-flight assessments of the boosters flown on the previous mission, STS-78. Engineers observed that hot gas had seeped into the J-joints of the STS-78 motor field joints. In some areas, the hot gas had penetrated through the J-joint to, but not past, the capture feature O-ring. Use of a new, more environmentally friendly adhesive was identified as the most probable cause for the leakage. The STS-80 motors were assembled using the original adhesive.
While booster stacking operations continued in the VAB, Atlantis was demated from its original booster stack and returned to Orbiter Processing Facility Bay 3, where some power-on operations were conducted. Access to the SPACEHAB module was set up through the orbiter crew compartment and some perishable items replaced.
The SPACEHAB remained inside the Shuttle during the destacking and reassembly. Target dates for the trip back to the pad included: mate orbiter to external tank, Aug. 13; rollout, Aug. 20; and Terminal Countdown Demonstration Test (TCDT), Aug. 27-28.