The International Space Station—An Orbiting Laboratory
IN A couple of years, when you gaze into a clear night sky, you may see not only the stars and the moon but also an artificial “star,” an object shining as brightly as the planets. The size of two football fields, this man-made colossus, which is already under construction, has been called ‘the biggest engineering project since the pyramids.’ What is it?
When it is completed, it will be the International Space Station (ISS)—a permanent space research laboratory created by more than 100,000 workers. Most of these are working in Canada, Russia, and the United States, but many others are in Belgium, Brazil, Denmark, France, Germany, Italy, Japan, the Netherlands, Norway, Spain, Sweden, Switzerland, and the United Kingdom. The completed ISS will be 290 feet [88 m] long and 356 feet [109 m] wide, with as much work and living space as the cabins of two Boeing 747 jets. The space station will eventually weigh 520 tons, and its construction will cost at least $50 billion!
Some critics who worry about such enormous costs in the name of research call the ISS “an interstellar white elephant.” On the other hand, its proponents expect the space station to provide a test site for new, advanced industrial materials, communications technology, and medical research. However, before astronauts can strap lab equipment to the walls of the ISS, it must be put together piece by piece, and all of this must be done in space!
Building It in Space
Because of its colossal size, the ISS could not be assembled on earth, since it would collapse under its own weight. To overcome this hurdle, scientists are building modules on earth that will be joined in space to form the space station. It will take 45 launches by Russian boosters and U.S. space shuttles to deliver these components into space.
Assembling the station is an unprecedented task, turning space into an ever-changing construction site. More than 100 modules will be joined while the workers and materials are in orbit. The international crew of astronauts must do much of the work by hand, performing many hundreds of hours of space walks.
The first module of the ISS—the 20-ton, Russian-built Zarya (meaning “Sunrise”)—blasted off on November 20, 1998, from the Baykonur Cosmodrome, in Kazakhstan. This module needed enough fuel to keep it and the other modules being added to it in orbit. Two weeks after Zarya blasted off, the space shuttle Endeavour carried aloft the American-built connecting module named Unity.
During that first construction session in space in December 1998, the Endeavour crew got a taste of the challenges ahead. During the rendezvous with Zarya 250 miles [400 km] above the earth, astronaut Nancy Currie used a 50-foot [15 m] robotic arm to grab that 20-ton module and clamp it onto Unity. Then, astronauts Jerry Ross and James Newman attached electrical and computer wires and fluid hoses outside the two modules. These connections are used to send power between the modules and to allow water to circulate for cooling the air and for drinking. It took three space walks, of more than 21 hours in all, to complete these tasks.
As rockets and shuttles deliver new modules every few weeks, the ISS will grow from the single Russian module Zarya to a 520-ton space station. Keeping that growing station in orbit will be a challenge, since it must resist the tug of earth’s gravity. So it is in constant danger of falling back to earth. To keep the station aloft, space shuttles will visit it and give the space station a boost to maintain its proper altitude.
The near-zero gravity will play an important role in the research conducted on the ISS, where gravitational force equals only one millionth of the strength of that force exercised on earth. A pencil dropped on earth would fall six feet [2 m] in 0.5 seconds. On the space station, it would take ten minutes! How will the ISS serve as a laboratory, and how can this affect your daily life?
The ISS is expected to be completed by 2004. Afterward, up to seven astronauts at a time will call the giant complex home. Some will live there for several months. On board this so-called window to the universe, the ISS crew will perform a diverse array of experiments designed by scientists from around the world.
For example, when the force of gravity is very weak, plant roots do not push down and leaves do not reach up. So scientists plan experiments to learn how plants behave in the absence of gravity. In addition, protein crystals grow bigger and become more symmetrical in space. Thus, purer crystals might be produced under such conditions. Information about this may help researchers develop medicines that target particular disease-causing proteins. In an environment where gravity is very weak, it may be possible to produce materials that are almost impossible to make on earth.
In near-zero gravity human bones and muscles deteriorate. Former astronaut Michael Clifford observed: “Part of the scientific research is aimed toward understanding the physiological effects of long-term exposure to space.” At least one experiment will be made to determine how bone loss might be combated.
Learning the long-term effects of living in space could perhaps help to make a long duration spaceflight to Mars possible someday. “That’s a fairly long trip,” Clifford acknowledged. “We want to have the capability of bringing [the space explorers] back in good shape.”
Additionally, supporters of the ISS predict that research on the space station will lead to a better understanding of the fundamental building blocks of life. Such an understanding could possibly result in new methods for treating cancer, diabetes, emphysema, and immune-system disorders. The laboratories on board the ISS will boast a bioreactor that grows cell cultures resembling natural tissue. Scientists will be seeking to learn more about human diseases and how to treat them successfully. Also aboard will be a 20-inch [50 cm] optical window to study atmospheric gases, coral-reef bleaching, hurricanes, and other natural phenomena on earth.
A “Laboratory for Peace”?
Nevertheless, for some of its fervent promoters, the ISS is more than just a floating laboratory. They see it as fulfilling a promise from the Apollo Program, which left a plaque on the moon that said: “We came in peace for all mankind.” After describing the ISS as a “laboratory for peace,” septuagenarian astronaut John Glenn added: “[It] will let 16 nations all work together in space instead of figuring out ways to do things to each other on Earth that aren’t good.” He and others see the ISS as a place where nations can learn to cooperate on science and technology projects that none can afford individually but from which all will benefit.
Many, however, cannot help but wonder whether nations will really cooperate peacefully in space, since they are unable to do so on earth. At any rate, the ISS is the result of man’s drive to step into the unknown and learn what happens under the conditions that exist there. Indeed, this mammoth project is a product of man’s sense of adventure and his passion for discovery.
[Box/Pictures on page 15-17]
DATES CONNECTED WITH SPACE STATIONS
1869: American Edward Everett Hale publishes a short story, The Brick Moon, about a manned brick space satellite above the earth.
1923: Romanian-born Hermann Oberth coins the term “space station.” He has in mind a starting point for flights to the Moon and to Mars.
1929: In his book The Problem of Space Travel, Hermann Potocnik outlines a plan for a space station.
1950’s: Rocket engineer Wernher von Braun describes a wheel-shaped station orbiting 1,075 miles [1,730 km] above earth.
1971: The Soviet Union launches Salyut 1, the first space station in history. Three cosmonauts stay in the station for 23 days.
1973: Skylab, the first U.S. space station, is put into orbit and accommodates three teams of astronauts. This station is no longer in space.
1986: The Soviets launch Mir, the first space station designed to maintain a permanent human presence in space.
1993: The United States invites Russia, Japan, and other nations to join in developing the International Space Station (ISS).
1998/99: The first modules of the ISS are launched into orbit—one year behind schedule.
Above: Artist’s conception of completed station in 2004
The first two modules, Zarya and Unity, are connected
Ross and Newman on their third space walk
A space shuttle launch, one of many planned
Pages 15-17: NASA photos