The launch of NASA'sPluto-bound New Horizons spacecraft is being delayed so engineers can performprecautionary boroscope inspections of the Atlas 5 rocket's first stage fueltank.
Liftoff had been scheduledfor January 11 from Cape Canaveral. But the extra work will slip the launch tono earlier than January 17, eating up the first six days in the year's 35-daywindow to dispatch the probe from Earth.
The NASA-orderedinspections stem from a problem experienced in September during factory testingof an updated Atlas 5 tank design. Lockheed Martin says a test tank failed justunder the "ultimate pressure" threshold it should withstand. That ledto workers reinspecting all of the tanks that had been produced in the factory.
The Atlas 5 rocket tolaunch New Horizons passed its check successfully. But now NASA wants toinspect the propellant tank's interior one more time to be safe.
The tank already containsthe flight load of RP-1 fuel to feed the rocket's RD-180 main engine duringliftoff. The highly refined kerosene was pumped aboard the vehicle during acountdown dress rehearsal earlier this month. That fuel will have to be drainedand the tank purged before the inspections can start.
Launch on January 17 willbe possible during a two-hour window opening at 1:24 p.m. EST (1824 GMT).Despite the delay, New Horizons can still achieve the desired trajectory thatswings past Jupiter for a sling-shot boost and reaches Pluto in 2015. Thewindow for that scenario runs through January 28.
Liftoff between January 29and February 2 would still include a Jupiter flyby but the arrival at Plutowould slip to 2016 or 2017 depending on the day of launch. More days areavailable for launch through February 14, but that would set up a direct routefrom Earth to Pluto that adds years to the trip because Jupiter will have movedout of alignment.
After mid-February thelaunch would have to wait a year before the next planetary opportunity linesup.
Meanwhile, the New Horizonscraft was set to travel Friday night from its Kennedy Space Center processing facility to the Atlas 5 vehicle assembly building at Complex 41. Thespacecraft will be mated atop the rocket on Saturday.