Soyuz TM-23
Soyuz TM-23 was a Soyuz spaceflight which launched on February 21, 1996, to Mir. The spacecraft launched from Baikonur Cosmodrome, and after two days of flight, Yuri Onufrienko and Yury Usachov docked with Mir and became the 21st resident crew of the Station. On September 2, 1996, after 191 days docked with Mir, the ship undocked with the launch crew and Claudie André-Deshays onboard, before eventually landing south west of Akmola, Kazakhstan.
Highlights
Onufrienko and Usachev began their mission without a third crew member. American astronaut Shannon Lucid would join them in late March 1996 during STS-76 and depart the Mir 20 mission in September 1996 with STS-79.Mir Principal Expedition 21
February 1996 – Mir 21 begins
Progress M-30 Undocked and Soyuz TM-23 Launched
On February 21, Soyuz TM-23 launched from Baikonur Cosmodrome with the cosmonauts for Mir Principle Expedition 21. To clear a docking port for the Soyuz TM-23, the Progress M-30 was undocked on February 22 and re-entered over the Pacific Ocean. The Soyuz docked on February 23 at the +X docking port on the rear of the Kvant module. An hour and a half after docking, the hatches opened and the Soyuz TM-23 crew were greeted by Yuri Gidzenko, Sergei Avdeyev and Thomas Reiter, members of Mir Principle Expedition 20 and Euromir 95. This began a week of joint operations where Mir 20 handed the station over to Mir 21, including familiarization with the current conditions of the projects and the station itself. Two days before the return flight, a water leak appeared in the Mir base block, but the cosmonauts were able to repair it.Mir 20/Euromir 95 mission ends
Gidzenko, Avdeyev and Reiter donned their Sokol launch and reentry suits and entered the Soyuz TM-22 on February 29, 1996. They landed safely about 105 km from Arkalyk. Their mission lasted 179 days, 1 hour and 42 minutes. Reiter then held the record for spaceflight duration by a Western European.March 1996 – Atlantis visits Mir for the third time
First EVA for Mir 21
On March 15, Onufrienko and Usachev exited the Kvant 2 EVA hatch for their first space walk. Because the existing Strela could not be used to reach the Kristall module in its current location, they installed a second Strela boom on the Mir base block, on the side opposite the Strela already in place. In the 5-hour, 51-minute EVA, they also prepared cables and electrical connectors on the surface of the Kvant module for the May installation of the Mir Cooperative Solar Array. The array was stored on the surface of the Docking Module that was installed on Kristall last November.Atlantis launched
The U.S. Space Shuttle Orbiter Atlantis was launched from Kennedy Space Center on March 22 at 11:00 UTC for its sixteenth flight as STS-76. During the ascent phase, flight controllers detected a small leak in one of Atlantis's three redundant hydraulic systems, but after the system was shut off when Atlantis reached orbit, the leak stopped. The approximately 20% loss of that one system's hydraulic fluid would not adversely affect the mission because the hydraulic system would not be used again until the descent phase.Preparations for docking
During the first two days of the mission, Atlantis Commander Kevin Chilton and Pilot Richard Searfoss began jet firings to guide Atlantis's journey toward Mir. The crew prepared for the docking by checking out communications equipment and docking and alignment aids. They also activated Spacehab and began orbital operations for Biorack experiments. Mission Specialists Linda Godwin and Michael Clifford checked out the space suits and equipment for their upcoming EVA.Atlantis approaches Mir
On mission day 3, when Atlantis was within 8 miles of the station, Chilton fired the orbital maneuvering system engines in the terminal phase initiation burn. As the two spacecraft completed another orbit, Atlantis approached Mir from below along the R-bar, using rendezvous radar to track its approach rate and measure its distance.Third Atlantis/Mir Docking
Chilton took manual control at one-half mile below the Mir, executing a 180 degree yaw rotation to align Atlantis with the Docking Module on Kristall. He used the ODS centerline camera as an aid in refining and maintaining the alignment. At 12:34 UTC on March 24, he achieved contact, adding Atlantis to a space station complex that then totaled 230 tons. After confirmation of docking, leak checks and pressurization of the docking vestibule, the hatches were opened and the two crews greeted each other. Shortly afterward, the Atlantis crew installed ducts to aid in circulating air between the two spacecraft during the docking phase.Lucid joins the Mir 21 crew
Shannon Lucid officially became a Mir 21 crew member at 12:30 UTC on March 24 after a joint "go" from the Russian and U.S. mission control centers. She became the first in a planned continuous U.S. astronaut presence on Mir until 1998.New supplies brought up on Atlantis
In the joint portion of the mission, the two crews loaded into the station more than 1 ton of U.S. science equipment, almost 2 tons of Russian supplies and 15 containers of water totaling about 1.5 tons. Approximately a ton of excess equipment, waste and science payload was transferred from Mir to Atlantis. From their vantage point in orbit, the crews were treated to a good view of the comet Hyakutake. Some of the spacecraft hardware items brought up by Atlantis were replacement gyrodyne, a seat liner kit for Lucid to be placed in a Soyuz module if emergency return to Earth was required and three Russian storage batteries which had been replenished on Earth.Experiment Supplies
Some of the new supplies and equipment for onboard experiments included replacement hardware for the Mir glovebox stowage experiments, Mir electric field characterization hardware to measure radio interference inside and around the complex, and a liquid phase sintering experiment that would use the Optizon furnace to bond different metals.Spacehab module work
On flight days 4, 5 and 7, the crew worked on the Biorack in the Spacehab module in the Orbiter payload bay. The Biorack contained eleven experiments to investigate the effects of microgravity and cosmic radiation on plants, animal tissues, bacteria, and insects. The various experiments were designed by France, Germany, the U.S., Switzerland and the Netherlands.Pre-EVA procedures
In preparation for the EVA, Atlantis's cabin air pressure was lowered from 14.7 to 10.2 psia. the hatches were closed between Mir and Atlantis and Atlantis and Spacehab throughout the EVA to allow for sustained cabin depressurization. The Mir crew, including Lucid, stayed inside Mir and the Atlantis crew stayied inside the Orbiter cabin, with Ronald Sega coordinating the space walk activities from inside.SAFER backpacks worn
Attached to their regular portable life support system backpack, Godwin and Clifford donned new self-contained backpacks with propulsion systems to allow enough free-flight capability to return an un-tethered astronaut to the spacecraft in an emergency. The device, called the Simplified Aid for EVA Rescue, was designed for EVAs on docked vehicles which would be unable to quickly retrieve a drifting spacewalker. The backpack was test-flown on STS-64 in September 1994.First EVA by U.S. astronauts at Mir
On March 27, Godwin and Clifford performed their 6-hour EVA in Atlantis' cargo bay and on the exterior of the Mir Docking Module. Their major task was to secure four experiment canisters to handrails on the docking Module. The experiments, collectively called the Mir Environmental Effects Payload, were designed to record data on orbital debris, and to test potential International Space Station materials by exposing them to the low Earth orbit environment. The four passive experiment canisters would be retrieved by a later STS crew after almost 2 years of data collection. During their work on the Docking Module, the astronauts also evaluated new tether hooks and foot restraints that could be used on both Mir and Shuttle Orbiter exteriors, prototypes of International Space Station EVA equipment. They also retrieved the Mir-mounted camera that had been used in docking alignment during STS-74 in November 1995.Atlantis leaves Mir again
The STS-76 and Mir 21 crews bid each other farewell on the morning of March 28. They closed the hatches to their spacecraft, and the astronauts began preparations for undocking and return to Earth. With the steering jets to both spacecraft shut down, Atlantis separated from the Mir Docking Module. Then Chilton reactivated the jets and slowly moved away from Mir. At 600 feet out, he began a fly-around, circled the station twice while the crews took pictures of each other's spacecraft, then moved to another orbit.April 1996 – a new module for Mir
Mir 21 continues with full crew
The daily flight plan, or cyclogram, for the Russian-U.S. crew was provided 4 days ahead of schedule by TsUP. A group of NASA science experts in Moscow served as consultants on science activities. The first week after Atlantis' departure, the crew focused on the Optizon Liquid Phase Sintering Experiment, processing 70 samples of different metals at high temperatures. The crew also conducted life sciences research and Earth observation photography. Space Acceleration Measurement System monitors were placed throughout the station to record movement that might disrupt experiments. Radiation dosimeters in various locations provided another measurement of the station's internal environment. A leak in a coolant loop in the core module was detected in mid-April, but the crew was unable to find the exact location. That loop was turned off and the alternate loop was used.The Priroda Module
The long-awaited launch of Priroda, earlier announced for March 10 so that the module would be in place when Lucid arrived at Mir, had been moved forward at least twice: once because of late delivery from the Khrunichev factory and once because a commercial Proton launch in early April took precedence. But on April 23, Priroda was launched from Baikonur atop a SL-13 Proton rocket for a three-day orbital trip to Mir. One of the two battery-powered electrical systems on the spacecraft dropped off-line, eliminating the backup power source for the automatic docking system. If the primary electrical system had also malfunctioned, the Mir crew would have immediately initiated a manual docking.The Priroda module had a mass of 19.700 kg, a length of ~12 m, a max diameter of ~4.35m and a pressurized volume of ~66 cubic meters. it was the last of the six permanent habitable Mir modules. Priroda was, like Spektr, designed by RKK Energia in the mid- to late-1980s and was built and assembled in the Khrunichev plant between 1989 and 1991. The module's two propulsion systems included one for orbit correction during the flight to Mir and rendezvous with Mir and one was for berthing and stabilization during the docking phase. The Priroda module included an unpressurized instrument compartment and an instrument/payload compartment.
The Kurs automatic docking system on Priroda worked flawlessly, as did the electrical system. No problems were encountered on the April 26 docking of the new module at the -X port at the front of the Mir base block.
On April 27, from inside the station, the Mir 21 crew controlled Priroda's repositioning with the Lyappa arm to the +Z docking port, directly across from the Kristall module. Thus the Mir complex, with its six habitable modules and Docking Module, attained its final basic configuration. Henceforth, the shape of the complex would change only temporarily, with dockings by Progress, Soyuz and Space Shuttle Orbiter spacecraft.
Because of concern about possible sulfur dioxide leaks from the malfunctioning battery system, a test of the modules' atmosphere was made before the crew entered. Once inside Priroda, the crew's first task was to unbolt the batteries, cap their connectors and place them in plastic bags. The 168 batteries would later be placed in Progress M-31 for disposal. The crew then connected Mir power sources to the Priroda systems and troubleshot the battery problems.