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WASHINGTON — Nothing in the design of the International Space Station should adversely affect long-term operations once construction is complete, but NASA should take steps to ensure that astronauts will have sufficient time to conduct the scientific experiments for which the station was intended, says a new report from the National Academies’ National Research Council. The report questions whether daily maintenance on the assembled station will leave crews little time for research, a problem that plagued the Russian space station Mir.

At the request of Congress, the Research Council formed an expert committee to evaluate NASA’s plans for supporting the space station after it is assembled. For the most part, the committee found the engineering behind the station’s design to be sound. However, it expressed concern that NASA’s focus on the assembly of the space station still leaves the need for important planning on how best to conduct research, operate the station, upgrade equipment, and make repairs, once the space station is functional. At the time of the committee’s study, construction of the space station was scheduled for completion in November 2004, after which it would be operational for 15 to 20 years.

"The long-term mission of the space station presents NASA with challenges quite different from those faced during the short-term manned space flights of the past four decades," said committee chair Thomas Kelly, retired president of Grumman Corporation’s Space Station Integration Division, now living in Cutchogue, N.Y. "NASA needs to look beyond the assembly phase, and develop plans now to maximize efficiency once the space station is operational."

Most of the engineering deficiencies in the design of the space station can be corrected with procedural changes and equipment or software upgrades and can be addressed in time to meet the scheduled completion, the committee said. In the meantime, NASA should conduct a rigorous analysis of typical crew activities to determine if crews will have enough time to conduct research. The space agency also should take advantage of the long stints that flight crews will experience aboard the space station — as well as the ingenuity crews have historically shown — by delegating responsibility for much of the day-to-day scheduling to them.


NASA should allow the astronauts carrying out experiments on the space station to exchange data and instructions directly with the principal investigators in charge of those experiments on the ground, a practice that saved time for the crew aboard Mir. Researchers on Earth should be able to use advanced communication techniques to control some of their experiments remotely with little assistance from the crew. Because many experiments will require attention from a crew member, however, NASA should consider including a payload specialist with research expertise as part of the seven-person crew.

For researchers controlling on-board experiments and mission-control staff to transmit communications to the space station at the same time, NASA needs to give high priority to efforts aimed at broadening the bandwidth — the capacity for carrying data along a communications channel — for messages sent from Earth to the station. Likewise, the space station antennas need to be relocated in a configuration that would allow uninterrupted communications between the station and Earth, the committee said.

NASA also should evaluate how real-time video transmissions could facilitate repairs on board the space station, the report says. And the space agency should explore reducing the number of staff on duty at mission control by turning to experts who would be on call and have ready access to data. With the safety of the crew and the success of experiments depending, in part, on secure, privileged communications, NASA should accelerate efforts to upgrade its encryption technology as well.

Because crew safety comes first, the crew return vehicle (CRV) is an essential part of the long-term planning process, the committee noted. In the event of an emergency, the CRV will be used to return to Earth. NASA must give higher priority to obtaining an appropriate vehicle, since the CRV needs to be in place by 2003 and a contractor has not yet been selected to build it. In addition, NASA should consider a remote-control return flight of the CRV from the space station to Earth to gain experience with its systems and flight characteristics.

The committee also reviewed plans for decommissioning the space station. At present, NASA plans to return the station to Earth by conducting a controlled re-entry over the Pacific Ocean, but the U.S. propulsion module, as presently designed, does not have the power to make such a maneuver. The committee agreed that this re-entry plan is the best way to decommission the station, but the propulsion module will have to be upgraded to provide the requisite power. And because of the potential hazards associated with re-entry of an object as large as the space station, safety requirements should be more stringent than for other NASA re-entry operations.


In light of the political and economic situation in the former Soviet Union, NASA is concerned about Russia’s ability to fulfill its role in the station’s assembly. NASA described to the committee the agency’s options for addressing these uncertainties, which involve providing short-term funding to keep assembly of the space station on track, while also seeking the necessary funds to eliminate American dependence on Russian participation. The committee urged NASA to carefully compare the costs of these options. It may turn out to be cheaper to continue providing funds to Russia rather than to transfer the cost of Russia’s responsibilities to the United States.

NASA is relying on Russian spacecraft as well as the U.S. space shuttle fleet to resupply the space station and change crews. The report says that because Russian and U.S. spacecraft could be grounded simultaneously, NASA should carefully reconsider its contingency plan. Currently, the plan calls for returning the space station crew to Earth and increasing the station’s altitude, which will conserve energy and keep the station in orbit until one of the shuttles arrives, or until space vehicles owned by the European Space Agency or Japan can reach it. But the committee said NASA should identify other viable options, and should consider new launch vehicles that may become operational during the lifetime of the space station.


NASA’s plans for how astronauts will walk in space and use robotic arms outside the station should be augmented to enhance the efficiency of crew members and ensure their safety, the report says. While the extravehicular mobility unit — the suit and life-support system used for space walks — is a proven system that can be expected to meet most of the demands of space-station astronauts, improvements are needed. For example, efforts should be made to reduce the time astronauts must spend in a depressurized chamber and the time spent breathing pure oxygen, both of which are done in preparation for space walks to prevent decompression sickness afterward. And NASA should ensure that the emergency propulsion system which astronauts rely on if detached from the space station can continue to function despite the failure of any one critical component.

NASA and its international partners should incorporate improved technology to increase the precision with which robotic arms can be manipulated outside the space station, the committee said. This is especially important since significant time may elapse between when astronauts are trained to perform tasks using the robotic arms and when they actually operate them in space, which could be several months later.

The committee’s report was funded by NASA. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit organization that provides advice on science and technology under a congressional charter. A committee roster follows.

Copies of ENGINEERING CHALLENGES TO THE LONG-TERM OPERATION OF THE INTERNATIONAL SPACE STATION are available from the National Academy Press at the mailing address in the letterhead; tel. (202) 334-3313 or 1-800-624-6242. The cost of the report is $18.00 (prepaid) plus shipping charges of $4.50 for the first copy and $.95 for each additional copy. Reporters may obtain a copy from the Office of News and Public Information at the letterhead address (contacts listed above).

National Research Council
Commission on Engineering and Technical Systems
Aeronautics and Space Engineering Board

Committee on the Engineering Challenges to the
Long-term Operation of the International Space Station

Thomas J.. Kelly* (chair)
Space Station Integration Division
Grumman Corp. (retired)
Cutchogue, N.Y.

John E. Blaha
Assistant Vice President of Applied Research
United Services Automobile Association
San Antonio

Bert Bulkin
Director of Scientific Space Programs (emeritus)
Lockheed Missiles and Space Co.
Woodbridge, Calif.

John T. Cox
Project Manager and Consultant
CSC Healthcare
Warrenton, Va.

Larry E. Druffel
Columbia, S.C.

Joel Greenberg
Princeton Synergetics Inc.
Princeton, N.J.

Herbert Hecht
Founder and Chairman of the Board
SoHaR Inc.
Beverly Hills, Calif.

Andrew J. Hoffman
East Windsor Associates
Broad Brook, Conn.

Jack L. Kerrebrock*
Department of Aeronautics and Astronautics
Massachusetts Institute of Technology

Dava J. Newman
Associate Professor
Department of Aeronautics and Astronautics
Massachusetts Institute of Technology

Stephen M. Rock
Associate Professor
Department of Aeronautics and Astronautics
Stanford University
Stanford, Calif.

Research Council Staff

Thomas J. Albert
Study Director

* Member, National Academy of Engineering