Digital Sprocket

Yesterday, the Space Shuttle Atlantis found itself at the center of a severe hailstorm. The spacecraft was slated for mission STS-117, an ISS construction flight, on March 15. During the 2-mile wide storm, the external tank and left wing suffered over 7,000 impacts from golf ball sized hailstones. Ground crews will roll the Shuttle back to the Vehicle Assembly building this weekend and conduct a more thorough inspection of the damaged areas. In 1999, the last time the external tank suffered hail damage, it took four days to repair the many small dings in the insulation.

Unfortunately, even a brief delay will force mission STS-117 to miss their March launch window. The Shuttle Atlantis and her crew will now have to wait until the next Soyuz flight delivers ISS Expedition 15 and departs the station. Since flight rules preclude having both vehicles flying at the same time, the Shuttle flight will launch no earlier than the April 20th. These delays are expected to have a small, but noticeable impact on the three other Shuttle flights scheduled for this year.

The main feature of mission STS-117 is the installation of the S-3/4 solar arrays. At the end of the flight, the ISS will once more be in a symmetrical configuration, and have enough electrical generating capacity to support the Japanese and European laboratory modules. Although the extra living space is not available yet, the new solar-voltaic wings will also provide enough power to run life support equipment for three additional crewmen. If JAXA and ESA’s automated cargo delivery vehicles work as advertised, the ISS may see a crew of six in the near future.