The fact that NASA is holding an Integrated Space Operations Summit (ISOS) in March is encouraging because it in that shows the agency is beginning to think seriously about some of the issues and decisions it will face in order to keep its space shuttles flying safely through 2010, the fleet’s planned retirement year.

Unfortunately, NASA’s five-year budget plan, as depicted in the agency’s 2006 funding request, does not seem to reflect some of the steps NASA likely will have to take to ensure that all goes smoothly during the shuttle phase-out. That could make for some unpleasant surprises down the road.

While it is typical in the budget planning process of most agencies to play fast and loose with future-year projections in order to secure funds for the year just ahead, programmatic reality has a way of coming back to rear its often ugly head. It wasn’t all that long ago, for example, that NASA woke up one day to find itself facing a $4 billion cost overrun on the international space station.

Sean O’Keefe, who at the time was deputy director of the White House Office of Management and Budget, forced NASA to come to grips with that reality by significantly scaling back its contribution to the space station program. Later, as NASA administrator, Mr. O’Keefe instituted reforms to the agency’s accounting practices in a bid to avoid future budgetary surprises.

But even Mr. O’Keefe was not immune to brushing aside inconvenient budgetary realities. In an interview on Aug. 28, 2003, just two days after the release of the Columbia Accident Investigation Board’s report, Mr. O’Keefe dismissed any notion that the cost of returning the shuttle fleet to flight might put pressure on other agency programs. Indeed, he confidently asserted that the cost would be “a very small fraction of what it costs to run the shuttle program.”

By January of this year, as Mr. O’Keefe was preparing to depart NASA for the greener pastures of academia, the return-to-flight bill had reached $1.5 billion, a very substantial fraction of the shuttle’s annual operating budget. And that number would have been much higher had U.S. President George W. Bush’s subsequent space exploration vision not relieved NASA of one of the Columbia board’s key requirements — recertifying the orbiter fleet for operations beyond 2010.

The disappearance of the recertification requirement and the elimination ng of some of the , along with upgrades that had been planned to keep the shuttle fleet flying well into next decade , likely has a lot to do with the fact that NASA ‘s projects its space shuttle budget to decline significantly as retirement approaches. The request for 2006 is $4.5 billion; that figure drops to $2.8 billion in 2009 and $2.4 billion in 2010.

Experience and common sense suggest those numbers are overly optimistic. For openers, space shuttle budgets dating back at least to the early 1990s have hovered in the $3 billion range. Because of the infrastructure and large, specialized workforce needed to operate the orbiter fleet, those costs tend to remain fixed, regardless of flight rate fluctuations.

While NASA will for e go certain shuttle upgrades, and production of some unique hardware will draw to a close before 2010, the resulting savings will be limited in part by the safety-driven need to hold onto key technical expertise right up to the bitter end.

As a case in point, an industry group slated to make a presentation to the ISOS meeting is likely to be among those recommending that NASA develop and implement a shuttle fly-out program that guards against the “going out of business mentality” that was cited in a rash of accidents in the late 1990s involving the U.S. Air Force’s Titan 4 rocket.

Such a program likely will include incentives designed to keep shuttle engineering talent from moving on to new and exciting development projects such as the crew exploration vehicle. NASA would be well advised to adopt such a program, and this will cost money.

In addition, NASA probably will have to maintain the capability to produce certain shuttle components, even after enough have been built for the remaining shuttle flights, until the agency figures out the solution to its heavy-lift needs for exploration.

The White House and U.S. Defense Department would prefer that NASA rely on a derivative of the Evolved Expendable Launch Vehicle for its exploration needs, but the shuttle-based option remains on the table and may well be the best answer for NASA’s needs. Preserving that option while the issue is being decided means paying to keep engineers and facilities associated with the space shuttle main engine, solid rocket boosters, external tank and perhaps other hardware available.

Development funding for a heavy-lift launcher — whichever option NASA chooses — will come from an account that is separate from the space shuttle. But the $1.2 billion set aside for that purpose in NASA’s five-year budget plan is nothing more than a placeholder at this point.

There are far too many unknowns to accurately predict how much money will be needed to ensure a smooth and safe transition from the shuttle to whatever succeeds it. The ISOS meeting marks the beginning of what will be a long and complicated process of sorting this out. NASA must pursue this effort with a sense of urgency, for it has little time to spare.