Mir (spacecraft)

FIELDS OF STUDY: Space Technology; Aerospace Engineering; Astronautics

ABSTRACT: Mir was a modular space station launched in stages between 1986 and 1996. Begun by the Soviet Union, it continued operations under Russia and international cooperation. It operated for fifteen years in orbit about 402 kilometers (250 miles) above Earth. During that time, it provided the first opportunity for prolonged stays in space. It gave scientists a way to study the effects of microgravity on human, plant, and animal life.

History of Space Stations

Mir was a groundbreaking space station, the first allowing extended space habitation. It was made possible by a relatively short but frantic period of technological development and space research. In the 1950s and 1960s, the world’s two superpower countries—the United States and the Soviet Union—were locked in the Cold War. Tensions were high between the two countries, and each was competing to gain advantage in any way possible. One arena for this Cold War competition was outer space, opened to exploration for the first time by rocket technology.

The Soviets took the early lead when they launched the first satellite into Earth’s orbit with Sputnik 1 in 1957. They then followed that up by putting the first person into Earth orbit in April 1961. A short time later, US president John F. Kennedy issued a challenge to the fledgling National Aeronautics and Space Administration (NASA) when he promised that the United States would put a man on the moon by the end of the decade.

While the Americans focused on the Apollo missions that would ultimately put not one but several men on the moon, the Soviets struggled with their attempts at lunar missions. Ultimately the Soviet Union instead focused much of its attention and resources on manned space stations. It launched the Salyut 1, the first space station in history, on April 19, 1971. The earliest designs for space stations could not be refueled or resupplied, so they were not meant for long-term use. Several other Salyut vessels failed. However, the Soviets did later launch three more Salyut stations that housed a total of five crews before turning their attention to long-term space station development.

As the Cold War died down, interest began to grow in combining knowledge and resources between the two superpowers. The joint Soyuz-Apollo mission in 1975 saw spacecraft from the two countries dock to each other and their crews meet. This was a precursor to the joint missions that would occur once the long-term Mir space station was launched.

Mir’s Groundbreaking Mission

The Mir space station was a modular space vehicle that made its way to space in pieces over a ten-year span. Its name derives from a Russian word that translates as "world" or "peace" but also refers to a system of government where the peasants owned and worked their own land. The core module was launched on February 20, 1986. It included all primary operating systems as well as crew quarters, areas for food service and hygiene, and storage. The first crew members arrived at Mir in mid-March 1986.

More modules began arriving just over a year later. These were attached to parts of the core module and to each other. The various sections and occasional rearrangements gave the full structure a somewhat haphazard look. Four modules came together at one point on their shorter ends, which some described as looking like four buses had collided in a four-way intersection.

Each module had a specific purpose. Kvant I, launched in 1987, included laboratories for astronomy and biotechnology. It also included a docking station used by some vehicles visiting the space station. Kvant II, launched in 1989, included an airlock and preparation area for extravehicular activity (EVA), including space walks. Kristall, launched in 1990, included solar panels and the docking station for the space shuttle. Spektr, launched in 1995, included remote-sensing equipment to study x-rays and gamma rays on Earth. This unit was damaged when an unmanned supply craft struck it in 1997. Priroda, launched in 1996, included remote-sensing equipment to study ecological issues on Earth.

The Mir mission was planned for five years, but the orbiter remained in service for fifteen, breaking all prior records for a vehicle’s useful time in space. Russia continued its operations after the fall of the Soviet Union in 1991. During its fifteen years in space, Mir hosted a total of 125 crewmembers from the Soviet Union, Russia, the United States, and other countries. A total of ninety-five vehicles docked with the space station. Among them were nine space shuttles, twenty-two other manned vehicles, and sixty-four unmanned cargo vehicles.

Several cosmonauts who were stationed on Mir set records for time in space. A few set progressively longer records of 326 days or more, but Valeri Polyakov (b. 1942) set the record with 438 days on Mir between 1994 and 1995. The record for overall time spent in space was set in 1999 by Sergei Avdeyev (b. 1956), who spent a combined 747.5 days in space over three missions.

Mir stayed in space three times longer than expected, but the space station also experienced some significant misfortunes, including damage incurred when an unmanned supply ship crashed into some of Mir’s solar panels in 1997. A fire that same year caused some frightening moments for the crew and led to improved space station safety regulations. The fire erupted during a routine oxygen replenishment maneuver. In order to boost the available oxygen aboard Mir, its crewmembers used perchlorate canisters to generate oxygen by a chemical reaction. But in February 1997, this routine procedure resulted in a fire that burned wildly while the crew struggled to put on gas masks and get fire extinguishers off the wall. They watched as metal burned and melted like wax from the intense heat of the blaze. Ultimately they were able to put it out without any injuries to the crew.

With some troubling issues developing, Mir began to require more and more costly upkeep. It needed regular boosting to maintain its low-Earth orbit. Russian space scientists began to focus their time and resources on a new project, the International Space Station (ISS). In 2000 Mir’s final crew began preparing the space station for deorbiting, and on March 23, 2001, Mir was allowed to fall into Earth’s atmosphere and burn up. Although many expressed concern that wreckage could crash into cities, the reentry was directed in an area over the South Pacific where it would cause no damage.

Lessons from Mir

Mir set a number of records during its time in space and was the base of operations for a number of important experiments. The most important might be the study of the effect of prolonged exposure to microgravity on human beings. Many of those who visited the space station spent far more time in space than had ever done before. By studying the long-term health of those who spent time on Mir and returned to Earth, scientists can better understand what must be done to prepare for future long-range planetary exploration missions or space habitation.

Experiments were also done with plant life on Mir. The first crops to be grown from seed to plant and back to seed were planted aboard the space station. Research into growing food crops in the microgravity of space will be important if humans are to attempt planetary exploration or establish permanent living spaces on other planets.

Mir also gathered vast amounts of information about stars and planets. Equipment in its astronomy laboratory was used to study quasars, neutron stars, and galaxies. Studies were also done of ecological conditions of Earth, including the condition of the ozone layer of Earth’s atmosphere and the temperature of the oceans. This will help in understanding climate conditions on Earth and identifying potential problems and solutions.

Even the problems aboard Mir provided learning experiences. Repairs to the exterior necessitated EVA, helping to refine such techniques for future space missions. The near-disastrous fire resulted in several improvements to the fire prevention and response methods used on later spacecraft. Changes were made to the way perchlorate canisters are manufactured and insulated. Stricter procedures about keeping areas near the canisters clear of combustible debris were set. Additionally, fire suppression technology and techniques were improved. Lastly, the focus on emergency preparation and drills to minimize panic that could cost lives was increased.

Many of these lessons had a direct impact on the next generation of space exploration, including the International Space Station. In continuous operation since November 2000, the International Space Station picks up where Mir left off, building on the multinational cooperation and the lessons that are part of Mir’s legacy. The work done on Mir will provide the building blocks for any missions to farther reaches of the solar system and possibly beyond.

Principal Terms

• extravehicular activity (EVA): all phases of a mission that take place while the crew member is in a specially designed pressurized suit in an unpressurized environment. These are commonly called space walks when occurring outside of a spacecraft. EVA can be a planned part of a mission or an unplanned addition to deal with a problem or urgent need.
• Soviet Union: the Union of Soviet Socialist Republics (USSR), a communist state established in the aftermath of the Russian Revolution of 1917. Following World War II, the Soviet Union and the United States raced for supremacy in space as part of the Cold War. The Soviets were the first to put a satellite in orbit, the first to put a human in orbit around Earth, and the first to launch a space station.
• space station: an orbiting space vehicle intended for long-term support of a human crew. Space stations include facilities for living and research in addition to the systems necessary to run the station. Crew members can enter and leave the space station while it remains in orbit by means of secondary craft used for transport.

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