Space Shuttle mission STS 103/Discovery has been cleared for launch on 6 December, to complete the third service of the Hubble Space Telescope. The spacecraft stack was scheduled to be rolled to launch pad 39B on 13 November.
NASA replaced the orbiter's main engine number three in the Vehicle Assembly Building (VAB) at the same time as it repaired a damaged solid rocket booster range-safety cable. A 1.3cm piece of a drill bit was left in the original main engine's combustion chamber. NASA had planned to launch with the original engine as the drill bit was not considered a safety hazard, but later decided on an engine change in the VAB, rather than on the launch pad, to save time.
Meanwhile, the next International Space Station (ISS) launch, of the Russian Zvezda service module on a Proton booster, has been delayed until February to fit into a new NASA Space Shuttle launch schedule for next year. This includes seven missions, six of which will be dedicated to the ISS.
The non-ISS STS 99 Shuttle Radar Topography mission will be flown on 13 January and will be followed by STS 101 Atlantis to the ISS on 16 March, assuming a launch of the Zvezda on a Proton is successful. STS 92, the next Shuttle ISS mission, will be in June.
According to the unofficial schedule, the ISS is already a year behind the schedule announced earlier this year.
Launches from Kennedy Space Center/Cape Canaveral this year in 1999 will only total 20 instead of the intended 35.
This is due to Shuttle flight delays and the grounding of Delta III and Titan IV boosters after launch failures, which also affected the Atlas fleet.
Source: Flight International
