The US space agency NASA on Friday delayed again, to no earlier than May 16, the date of shuttle Endeavour’s launch for a servicing mission to the International Space Station, officials said.
The already-postponed flight, the next-to-last in the shuttle program, has been on hold since April 29, when a problem developed with one of the ship’s auxiliary power generators about four hours before the scheduled lift-off.
Workers replaced a faulty electronics box and are retesting the myriad of shuttle systems that draw power through it.
NASA initially retargeted the flight for today, but when the extent of the repair became apparent, managers postponed the launch to no earlier than Tuesday. That date, likewise, proved too optimistic.
Engineers have been unable to determine the root cause of the box’s failure and are replacing external wiring in case the problem originated from outside the device.
The extra work led managers on Friday to reset the launch date for no earlier than May 16, NASA spokesman Kyle Herring said.
“There is still some uncertainty because we have to get past all the work. We’ll regroup on Monday and see how far they’ve gotten over the weekend, but the [May 16 launch date] looks pretty good right now,” Herring said.
Managers also decided to add two days to Endeavour’s planned 14-day flight. The shuttle will be carrying a US$2 billion Alpha Magnetic Spectrometer particle detector and spare parts to the space station.
NASA will have until May 26 to launch Endeavour before other issues would delay the mission into next month.
Endeavour’s mission is the next-to-last in NASA’s 30-year-old shuttle program which is being phased out. A final supply run is planned by shuttle Atlantis this summer.
In a separate development, the launch of an unmanned rocket carrying a next-generation US military missile-warning satellite was delayed on Friday because of cloudy skies at the Florida launch site.
The launch of the rocket known as the Atlas 5 was pushed back to yesterday, said Don Spencer, launch commentator for United Space Alliance, a joint venture between Lockheed Martin Corp and Boeing Co.
The rocket carries a US$1.3 billion Space-Based Infrared Systems (SBIRS) Geo-1 spacecraft built by Lockheed Martin and Northrop Grumman Corp.
The satellite is the first of four planned for launch over the next five years in the US$17.6 billion SBIRS program, which also includes sensors on other host spacecraft.
The network is designed to give the military early notice of missile launches and provide other reconnaissance services. The SBIRS network will eventually replace the Defense Support Program (DSP) satellites, which went into operation in 1970.
The last of 23 DSP spacecraft was launched in 2007, although it failed in orbit. Northrop Grumman Space Technology, formerly TRW, built all 23 DSP satellites.