While the space shuttle Discovery has successfully returned NASA to human spaceflight, it has also added pressure on the U.S. space agency to move beyond the shuttle program.
The Discovery mission, indeed, blended success and frustration, hope and poignancy. The shuttle program manager, William Parsons, called it a "wildly successful mission." But the launching was delayed repeatedly, and a problem with a fuel level sensor forced mission controllers to scrub a planned effort July 13, just 2Ѕ hours before liftoff.
And though modifications made to the external fuel tank resulted in far less launching debris, five large pieces of foam popped off the tank, showing that a potentially fatal problem had not been fixed. NASA has said that until the foam mystery was solved, shuttles would not fly.
The somewhat rocky resumption of shuttle flights could end up accelerating the country's shift to the post-shuttle era, aerospace experts and analysts say. They contend that the suspension in shuttle missions could speed the demise of the winged spaceships, already headed for retirement by 2010, and give new urgency to taking the next step in human space exploration.
"It's a good time to take a step back and think about the future of the space program," Roger Pielke Jr., director of the Center for Science and Technology Policy Research at the University of Colorado, said in an interview. "Choosing not to fly the shuttle would open up resources to get on sooner with what comes next."
In the weeks ahead, NASA plans to release blueprints for new space vehicles derived from shuttle parts, though experts debate whether the agency can afford to pursue old and new approaches simultaneously, reports Herald Tribune.
According to Newsday, NASA plans to fly its three remaining shuttles until 2010 in order to complete the space station. By 2014, the work will begin to shift operations to an as-yet-undersigned Crew Exploration Vehicle, along with a mix of unmanned spacecraft.
NASA Administrator Michael D. Griffin has rejected as "overreaction" the view of critics that the shuttle is a white elephant that should be retired early.
Despite at least three foam failures on Discovery that exceeded pre-flight limits, he insisted that the mission as a whole was remarkably clean.
Detailed in-flight surveys revealed only about 25 "dings" in the spacecraft's heat shield surfaces, one-sixth as many as the previous average of 145 per flight.
"In the world of engineering," he said, "we did pretty well."
Although he has led NASA for less than four months, Griffin took responsibility for failing to solve the foam problem. But he added, "All we can do at this point is move forward."
At his direction, the space agency has formed several engineering teams to investigate the insulation problem, with help from the tanks' builder, Lockheed Martin. They will report to space station program manager Bill Gerstenmaier, who was to get his first briefing yesterday.