The International Space Station will be a permanent laboratory for human-monitored long term research in the unique environment of Earth-orbital space, an environment that cannot be replicated on Earth for long duration experiments. Research at the station will focus on two key areas: life sciences and materials sciences.
Life sciences research is expected to lead to a clearer understanding of basic processes and that will provide a foundation for development of advanced medications for improved human health. Materials research offers promise of improved metals, composites and plastics for significant advances in technologies for communications, transportation and a broad range of industrial processing operations.
The International Space Station draws upon the resources and scientific/technological expertise of 13 cooperating nations, including the U.S., Canada, Japan, Russia and nine nations of the European Space Agency(Belgium, Denmark, France, Germany, Italy, Norway, Spain, the Netherlands and the United Kingdom). The prime contractor is The Boeing Company and the principal subcontractors are McDonnell Douglas Corporation and the Rocketdyne Division of Rockwell International.
While the Phase I flight program advanced to orbital docking operations in 1995, manufacturers were turning out the first hardware components of the space station. By January 1995, 25,000 pounds of station hardware had been built; it was estimated that the total would reach 100,000 pounds by the end of 1995.
A major piece of flight hardware was rolled out in April 1995: a large Boeing-built module known as a node that will serve as a storage area, a housing for electrical power conversion equipment and as a connecting passageway between the living and laboratory quarters of the space station. The Node 2 will be used for pressure and leak tests and join the space station complement in 1999. In the meantime, Boeing will put the finishing touches to Node 1, whose exterior structure was completed in July 1995; Node 1 will be the first U.S. hardware delivered to orbit. Boeing is building a third node.
Phase II of the space station construction program will begin in November 1997 with the launch on a Russian Proton vehicle of the "FGB." The FGB is a 42,600-pound element, built in Russia but purchased by the U.S., that includes the energy block, contingency fuel storage, propulsion and multiple docking points.
A month later the Boeing node will be delivered by the Space Shuttle and attached to the FGB. In May 1998, the embryo space station will grow with the addition of the Proton-boosted Russian Service Module, which provides life support and habitation facilities, utilities and thrusters. Shortly thereafter, the crew transfer vehicle - a Russian Soyuz TM capsule - will be joined to the station. At this point, the station will be able to accommodate long duration stays of three - person crews.
Further additions to the expanding station in the latter part of 1998 and early 1999 will include one of the four U.S. solar array modules, which will provide about 23 kilowatts of power; the U.S. laboratory module; the Canadian-built mobile servicing system; and a utilization flight bringing up equipment for outfitting the laboratory module.
In April 1999, Phase II will end with the completion of assembly and outfitting of the interim human-tended configuration of the International Space Station, shown above. The large segment at the top is the 112-foot-long U.S. solar array module. The FGB is in the center of the photo; docked with it at far left is the Russian Service Module and below it the Soyuz TM crew transfer vehicle. At the right end of the station is the U.S. laboratory module and Node 1, a storage module. Atop the laboratory is the Canadian mobile servicing system.
In Phase II, the International Space Station will progress gradually from human-tended capability to its ultimate status as a fully operational permanent orbital research facility. Among key additions to the human-tended core configuration are the remaining modules of the U.S. solar array; the Japanese Experiment Module (JEM), to be delivered in March 2000; the European Space Agency (ESA) laboratory, February 2001; and the U.S. habitation module, February 2002. In June 2002, station assembly will be completed with the addition of a second crew transfer vehicle, which will provide an emergency evacuation capability for a full crew of six.
The completed station, shown below, will measure 361 feet from tip to tip of the solar arrays. That corresponds to the length of a football field, including both end zones; however, the area covered by the station complex is equal to that of two football fields. The pressurized living and working space is roughly equivalent to the passenger cabin volume of two 747 jetliners.
There will be seven laboratories. The U.S. is providing two of them, the basic laboratory module and a Centrifuge Accommodation Module. There will be three Russian research modules, the Japanese JEM and the ESA's Columbus Orbital Facility. The U.S., ESA and Japanese laboratories together provide 33 International Standard Payload Racks; additional payload space will be available in the Russian modules. In addition, the JEM has an exposed "back porch," with 10 mounting spaces for experiments that require long duration contact with the space environment; the JEM has a small robotic arm for mounting and moving back porch payloads.
The ESA module is visible to the left of the Orbiter, the JEM (marked NASDA) to the right. The central structure connecting the modules and the main solar power array is the U.S.-built integrated truss; generating a combined 92 kilowatts, the four modules of the power array rotate on the truss, maximizing their exposure to the Sun.
At the "rear" of the station assembly is the Russian service module. The vertical structure next to the service module is the Russian-built Science Power Platform (SPP) with its own solar array; the SPP provides additional power and heat rejection for science and operations. Just above the Orbiter's node, on the integrated truss, is the Canadian module servicing system with its 55-foot robot arm and a mobile transporter that enables it to move along the truss for robotic assembly and maintenance operations.
The International Space Station will operate at an altitude of 240 miles. At that altitude, minute drag forces will cause the station to lose height very gradually, so it will be necessary to reboost it every 90 days. The reboosting will be accomplished by the FGB.
Beginning with the 1997 launches of the Russian Proton and the Space Shuttle, there will be 73 flights until fully operational status is attained in June 2002. The Space Shuttle will make 27 flights, 21 for assembly operations and six for utilization/outfitting. The Russian Proton and Progress, and Ukrainian Zenit launch vehicles will make 45 flights; 19 of them will be made by the Progress vehicle, bringing up propellant for the FGB's reboosting work. There will also be one flight of the Ariane 5 launch vehicle for delivery of ESA's Columbus module.