NASA and its international partners unveiled a new space station assembly sequence today, one that takes into account the looming 2010 end of the shuttle program by deferring science operations in favor of construction flights to ensure completion of the orbital outpost.

While not addressed by the assembly sequence, a proposed shuttle mission to service the Hubble Space Telescope, if approved, would come after the launches of European and Japanese space station modules, sources say.

The new schedule shows the station capable of supporting a crew of six by the 14th flight in the assembly sequence. Two additional flights are listed as contingency missions.


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The revamped assembly sequence was unveiled by NASA Administrator Mike Griffin today after a "heads of agencies" meeting at the Kennedy Space Center. It is the first assembly plan that fully takes into account President Bush's 2004 directive to complete the station and retire the space shuttle by 2010 and develop a new spacecraft to return astronauts to the moon by the end of the next decade.

The European and Japanese space agencies lobbied NASA to accelerate the launches of their pressurized laboratory modules after years of delays, most recently due to downtime following the 2003 Columbia disaster.

The new sequence moves up launch of Europe's Columbus module to the seventh shuttle flight and moves up launch of Japan's Kibo module two flights, to the ninth mission.

Griffin said today that moving up the launches of the international modules was a "minor adjustment" to the assembly sequence.

"I think everyone is focusing on quote moving up the labs unquote inappropriately," he said. "There has been some minor adjustment of the sequence. What you're seeing today ... is the result of 10 months of work between the United States and our partners following my comments immediately after being confirmed as administrator that a 28-flight shuttle assembly and utilization sequence was not possible within the remaining lifetime of the space shuttle program, that we simply did not have the flights in the system to be able to do it. Not everyone agreed with that judgment and I regret that. But that was my judgment. And so we focused on redefining the station assembly sequence, in fact, to concentrate on assembly."

At the time of the Columbia disaster, the station assembly plan included both construction flights and so-called "utilization" missions aimed at conducting research while construction was taking place. Given the president's directive to end shuttle operations in 2010, "we are largely deferring utilization and we are paring logistics to the bone," Griffin said.

"We don't like that. But confronted with a choice between having the high confidence to be able to complete the assembly of the station and deferring utilization, or utilizing it heavily as we built it and possibly not finishing, we chose the former course. Now, as a result of taking that course of action, meaning to assemble now and utilize largely later, there has been some adjustment to the flight sequence regarding the labs."

But he said, "the main thing you're seeing here today is not adjustments in the flight sequence, but the decision to put together an assembly sequence that allows us to have very high confidence that we will finish the space station assembly by the time the shuttle must be retired."

Here is the new assembly sequence as approved by NASA and its international partners. Shuttle vehicle assignments and flight designations are under review except where shown:

1. ULF1.1 (Discovery/STS-121) - Test flight; station logistics and resupply

2. 12A (Atlantis/STS-115) - Port 3/4 solar array truss elements; second set of solar arrays

3. 12A.1 (Discovery/STS-116) - Port 5 solar array truss element

4. 13A (STS-117) - Starboard 3/4 solar array truss elements; third set of solar arrays

5. 13A.1 (STS-118) - Starboard 5 solar array truss element

(ATV1 - First flight of ESA unmanned cargo vehicle)

6. 10A (STS-120) - Node 2 connecting module

7. 1E - European Space Agency's Columbus module

8. 1J/A - Japanese experiment logistics module (pressurized section); Canadian robot arm dexterous manipulator

9. 1J - Japanese Kibo research module

10. 15A (STS-119) - Starboard 6 solar array truss element; fourth set of solar arrays

11. ULF2 - Logistics, utilization flight

(3R - Russian laboratory module and European robotic arm)

12. 2J/A - Japanese experiment logistics module (exposed section)

13. 17A - 3 crew quarters; second treadmill; six-person crew capability

(HTV1 - First flight of Japanese cargo vehicle)

14. ULF3 - Logistics, utilization flight; spares prepositioning

15. 19A - Logistics, resupply; experiment support pallet

(ULF4 contingency flight)

16. 20A - Node 3 connecting module with cupola; ASSEMBLY COMPLETE

(ULF5 contingency flight)

(9R - Russian research module)

NASA hopes to launch the shuttle Discovery in May and two more missions before the end of the year to get station assembly back on track after delays caused by the Columbia disaster and foam insulation problems discovered during Discovery's return to flight last July. Launch is targeted for May 10, but the flight could slip into July because of time needed to complete extensive testing, analysis and hardware processing.