The space shuttle Atlantis, bolted to a mobile launch platform atop an Apollo-era crawler-transporter, was hauled to launch pad 39A at the Kennedy Space Center on Tuesday for work to ready the ship for blastoff May 12 on a fifth and final mission to service the Hubble Space Telescope.
Originally scheduled for launch on October 14, the long-awaited Hubble overhaul was delayed when one channel of a critical data-processing system unit aboard the telescope failed just two weeks before liftoff. NASA managers decided to replace Hubble's entire science instrument command and data handling unit, or SI/C&DH, to restore redundancy and improve reliability.
But testing a spare ground unit at the Goddard Space Flight Center in Greenbelt, Md., getting it certified for flight, and working the mission back into NASA's shuttle manifest ended up delaying Atlantis and Hubble Servicing Mission 4, or SM-4, for seven months, when all was said and done.
The replacement SI/C&DH was delivered to the Kennedy Space Center on Monday, and Atlantis, attached to an external fuel tank and two solid-fuel boosters, took its first step toward space with a six-and-a-half-hour, 3.2-mile trip from the Vehicle Assembly Building to pad 39A on Tuesday.
Shuttle commander Scott Altman, pilot Gregory C. Johnson, flight engineer Megan McArthur, and spacewalkers John Grunsfeld, Michael Massimino, Andrew Feustel, and Michael Good plan to fly to Kennedy late this week to inspect the replacement computer unit before it is moved to the pad April 18, along with the rest of the Hubble payload, for installation in Atlantis' cargo bay.… Read more