Delays in the space shuttle program could force a one-month slip of an early test flight of NASA's next-generation rocket next year due to busy Kennedy Space Center launch facilities, agency officials said Thursday.

An artist's concept depicts the Ares 1-X test vehicle on the pad for its 2009 liftoff. Credit: NASA

The schedule issue stems from the delayed production of new shuttle external fuel tanks at a Lockheed Martin Corp. factory near New Orleans. The work is taking longer than predicted, and shuttle managers will likely postpone the shuttle Atlantis' mission to service the Hubble Space Telescope from late August to early October.

Plans call for two shuttles to be simultaneously prepared for flight in case a rescue flight is ordered to retrieve Atlantis' seven astronauts if major damage is found in the shuttle's thermal protection system tiles and panels.

The unique rescue requirement means the shuttle Endeavour will be prepared for launch from pad 39B, a complex that has been out of operational service since December 2006.

The delay of the Hubble repair mission will extend the shuttle program's hold on the launch pad, a mobile launch platform and an assembly bay inside the cavernous Vehicle Assembly Building.

The facilities need to be transferred to the Constellation program several months before the Ares 1-X mission, a $350 million launch of a scaled back first stage of the rocket NASA will use to launch the Orion piloted spaceships.

Officials estimate the schedule holdup will cause a day-for-day slip in the Ares 1-X launch.

The new launch date could be in late May 2009, four-to-six weeks later than the flight's current target of April 15, according to Jeff Hanley, Constellation program manager.

"We are doing what we can to look at what could be done to do parallel work or other ideas that might be in play to get the modification work to the Mobile Launch Platform done and still mitigate some of that impact to the 1-X launch date," Hanley said. "But if we can't come up with anything and it has to be a day-for-day slip ... that's perfectly workable."

KSC engineers are already moving ahead with work to install cleats to hold water bags inside the launch platform's right solid rocket booster hole, which will be left empty for the Ares 1-X mission. Technicians will also add electrical connectors for an umbilical between the ground and the rocket's first stage, and workers will put in a heritage ground control system from the Atlas rocket program, said Tracy Young, a KSC spokesperson.

The mobile platform will be carried to the pad for validation testing before engineers begin assembling the Ares 1-X components. Technicians will start stacking the rocket about eight weeks after the MLP is handed over to the Constellation program, Young said.

Most of the modifications to the launch pad will not begin until after Atlantis returns to Earth and Endeavour is moved to pad 39A to resume normal processing.

The pad's Fixed Service Structure will be raised 100 feet feet and a new lightning tower will be added atop the complex to help protect the 309-foot tall Ares 1-X rocket from dangerous weather. That task should be completed by January, Young said.

Hanley said the rippling effect of the shuttle delays is not surprising because both programs share the same facilities.

"We walked into it with our eyes wide open that this could happen," Hanley said. "When those assets become available to us, that's when we'll go and press to launch."

Officials expect Ares 1-X flight hardware will begin arriving at the launch site this fall, beginning with roll control system parts in September. The four segments of the solid rocket booster first stage, a static fifth segment, and the dummy upper stage will be transported to KSC in October. A model of the Orion capsule and the launch abort system is expected at KSC by November.

The delay of the Ares 1-X mission should not affect future milestones in the rocket's development, Hanley said.

"The Hubble slip and the 1-X launch date are really not in what I would call the near-term critical path for the first launch of Ares 1," Hanley said.

Steve Cook, the Ares 1 rocket project manager, said he wants the flight data from the Ares 1-X launch at least six months before the rocket's critical design review in March 2010, an important signpost in the booster's early development.

"We would like to have the 1-X data in our hands no later than the fall of 2009, so that kind of gives us about six months worth of margin on 1-X getting off for flight," Cook said.