With a new NASA administrator on the way and pressure growing on the U.S. space agency to refurbish the Hubble Space Telescope, there is now a good opportunity to draft an affordable plan that will keep Hubble productive into the next decade. That must happen in a way that does not prevent the agency from moving ahead in a meaningful way with a new exploration agenda focused on a return to the Moon and eventual human missions to Mars.

It can be done if Congress, the White House and Mike Griffin, the president’s nominee to head NASA, work together to reshape NASA for the future. The key is the space shuttle; or more precisely, making absolutely sure that the space shuttle is retired by the end of 2010 or sooner. The best way to do that is to cut back sharply on the number of planned shuttle missions, which currently stands at 28.

While former NASA Administrator Sean O’Keefe would never publicly acknowledge it, one of the big problems agency officials saw with sending another shuttle to service Hubble was that it disrupted the space station assembly schedule and prolonged the life and expense of the shuttle program, which costs taxpayers $4 billion a year. Each additional month the shuttle program lasts is one more month that NASA must keep a very expensive standing army intact. On that count these officials were right, and it is one of the reasons the shuttle manifest needs to be cut as much as possible.

Mr. O’Keefe always insisted that his decision to cancel a planned shuttle mission to service Hubble was based solely on his concern for crew safety in the wake of the Columbia accident. He decreed that all future shuttle missions be sent only to the international space station. His rationale was that the space station was the best place for repairing a shuttle damaged on its way to orbit or, if repair proved impossible, providing safe harbor for the crew while a rescue mission was prepared.

Even Hal Gehman, chairman of the Columbia Accident Investigation Board, declined to buy into that rationale when O’Keefe asked him to review the decision to cancel the shuttle-based Hubble servicing mission. Mr. Gehman said flatly that restricting future shuttle missions to the space station was not one of the board’s requirements for resuming shuttle missions.

To put it simply, if the shuttle is safe enough to fly to the space station repeatedly, it is certainly safe enough to fly to Hubble once. NASA has spent the last two years making safety changes to prevent a repeat of the Columbia nightmare. It is probably as safe as it is going to be.

For all of its incredible capabilities, the shuttle can be a very unforgiving vehicle. It will always be risky and the sooner it is retired the better. In the meantime, it should be reserved for priority missions, and Hubble certainly can be one of those. Despite the billions of dollars that have been spent on the station, many scientists would rank keeping Hubble operating as long as possible a much higher priority than anything involving the space station.

Cutting back on space station assembly missions will make room in the shuttle manifest for a Hubble mission to deliver new gyroscopes, batteries and two already-completed instruments that promise to keep the telescope producing world-class science well into the next decade.

While a robotic mission to Hubble might have accomplished those tasks as well while giving the nation an important new capability in space, NASA’s latest estimates show that it is still a $1.3 billion to $1.5 billion undertaking. In addition, there are technical risks that lead to legitimate uncertainty about whether such a mission would be ready to launch before 2008, when Hubble’s gyroscopes are expected to fail, bringing science operations to a halt.

The money saved by cutting back on shuttle flights could be used to accelerate development of a Crew Exploration Vehicle.

Fewer shuttle flights would mean more money across the board to help Mr. Griffin jump-start the president’s exploration agenda. That agenda is vital to NASA’s future and should not be deferred to placate those who want to cling to the status quo.