And while the jury is still out as to whether history will deem the space station a success, the shuttle almost certainly will be remembered for its dramatic failures as much as the significant accomplishments its yeoman-like crews achieved
since Columbia first flew in April 1981.In the meantime, there is enough work to go around for both the shuttle and the ISS. Before the shuttle fleet is retired in 2010, their crews are scheduled to fly nine more missions to the station.
Five will involve installation of new equipment; two are more akin to space-borne teamster jobs, hauling supplies and parts.
Shortly thereafter, the Constellation program, with its Ares launch vehicle and Orion spacecraft, will be ready to take over the mission of carrying people into space for the next 30 to 40 years and expand the limits of the space frontier beyond low Earth orbit
The ISS, fully complete by then, will assume the shuttle's role as an orbiting laboratory.
At that point, the space shuttle will be relegated to museums, where the first thoughts that will come to most visitors' minds will no doubt involve the catastrophic losses of Challenger in January 1986 and Columbia in February 2003.
Such reactions may be overly simplistic, but they are understandable in the eyes of some who were close to the shuttle program.
"The shuttle is a remarkable technological achievement, but it is an equally remarkable policy mistake," says John Logsdon, the chairman of the Space Policy Institute at The George Washington University in Washington and a former member of the NASA Advisory Council. He also served on the Columbia Accident Investigation Board.
The key error was the collective belief of the shuttle's champions that "it could be a system that could operate inexpensively, routinely, and with a high level of safety," Logsdon says. "It met none of those objectives."
An "incredible ship"
Those shortcomings are recognized within NASA — hence the willingness throughout the agency to embrace Administrator Mike Griffin's push toward Constellation as the next logical step toward the return to the Moon and the first trip to Mars.
The shuttle is an "incredible ship," says Mike Hawes, program integration manager at NASA's Space Operations Mission Directorate. "It launches like a rocket, flies like a satellite, lands like a plane, and has cargo capacity — particularly a return cargo capacity that's huge."
With the shuttle, NASA learned how to mechanize regular access to space, and came to terms with both the good and bad challenges of reusable spacecraft, Hawes says. Until scramjet and ramjet technology gets off the drawing boards and test bays and joins flight lines, the shuttle remains the only fully hypersonic vehicle ever to fly regularly and carry crews and payloads as well. The data on high-speed aerodynamics collected during shuttle missions will serve the designers and engineers of future ultrafast winged aircraft well, he said.
The shuttle also performed well when called upon to support missions to build the space station, Hawes says, providing a platform for extravehicular activity as well as deployment for space arms and other complicated assemblies.
"But we learned it was a very expensive machine to operate, care and feed," Hawes says. "And another thing — because of its long life cycle and small numbers — the total production run of orbiters being five — there are unique challenges in maintaining an industrial base."
The shuttle's unmet aspirations can be traced to the unrealistic conglomeration of functions it was supposed to perform from the beginning, says Howard E. McCurdy, a professor of public affairs at American University in Washington and author of white papers that outline how NASA could operate more efficiently.
"It's important to keep in mind the huge controversy, going back to the 1950s, whether a spacecraft should have wings," says McCurdy. "Should it have a ballistic shape? We go back and forth on that."
Fixed-wing advocates prevailed, McCurdy says, convincing decision- makers that "the X-15 plus reusability equals one-tenth of the cost" of reaching space. Future generations of shuttles were supposed to do the job even better, he says, recalling former NASA Administrator Daniel S. Goldin's hopes of someday deploying shuttles back and forth from space with the reliability of combat fighter aircraft.
Further complicating matters, McCurdy says, "The project was in a perpetual state of redesign — not just by the engineers, but by the people who were providing the money." Engineers were "driven crazy," he says, by the responses they would receive from contractors, field engineers, even political types, who had the audacity to come back with submissions of drawings with their own ideas of what the craft should look like.
"As they say on Capitol Hill, it [was] the only train in the station. It involved large amounts of money, infrequent new starts. Everybody gets involved," McCurdy says.
At that point, projects like the shuttle take on the characteristics of any big undertaking. Because so many people have so many different objectives, it became unwieldy and hard to manage.
"The same thing was true with the space station in the beginning," McCurdy says. While some supporters wanted the ISS to carry hangars for satellites, others wanted space telescopes. The two are mutually exclusive, he says; you cannot have a space telescope on one end of a platform and somebody banging on some piece of hardware in a satellite bay on the other end.
That collective mentality is "one of the reasons why we spent tens of billions of dollars on the space station but got nothing but a bunch of Power Point presentations," McCurdy says.
A city in space
Now, as the ISS takes shape, it is emerging as a significant milestone in the history of cooperative ventures among nations.
The space station's scientific missions, from the U.S. standpoint, chiefly surround resolving issues related to survival in space. Until we learn how to reduce bone mass loss and mitigate the potentially deadly effects of long-term exposure to radiation, there will be no manned missions to Mars.
"But we can talk about science all we want, but really, international relations are the most important thing," says Roger D. Launius, the curator of the National Air and Space Museum and former chief historian at NASA. "That 16 nations [came] together to build the thing peacefully is a very significant development. It never happened in past human history, and quite frankly this may be the end of it, [given] the strife in the world and new strains between us and Russia."
The collaboration may appear touchy-feely to laypersons, but to engineers and scientists it is anything but. Construction and deployment of Canada's shuttle arm, the European space laboratory and the Japanese science missions meant that the task at hand became "truly multilateral," says Hawes.
Adding the entry of Russia into the mix in the early 1990s led to appropriate increases in potential complications to the matrix. U.S. and Russian teams had to learn to communicate in each other's language of program management and engineering.
"We learned there is no one formula to doing [international] partnerships," Hawes says. "What do you mean when you're talking about 'verification?' How do you test for structural strength? We found as we integrated the Russians that some [methods] are similar and some are different. Once we got past the language issue, we were able to build hardware that works once it gets into space, without ever seeing its physical counterpart on the ground."
The science, Hawes believes, will sort itself out after the ISS expands to a six-person crew, up from the present three.
"We'll have much larger capacity to do science both in terms of increased test subjects in which the crew is part of our experiment, and also the crew time to apply to a broader range of experiments," Hawes says.
SPACE.com -- NASA at 50: The Shuttle, Space Station and Beyond
