In addition, astronauts Jim Newman and Carl Walz are scheduled to perform a six hour spacewalk on the fifth day of the mission as a continuation of a series of test spacewalks to increase experience and refine training methods. They will work with several tools that may be used during the servicing of the Hubble Space Telescope mission later this year. Today in Firing Room 1 of the Launch Control Center, the KSC launch team is verifying systems to assure that the Shuttle is powered up and that the data processing and backup flight control systems are operating trouble free. Verifications will be conducted throughout the count to ensure reviews are being made of the flight software which is stored in the orbiter's twin memory banks. Computer controlled display systems will be activated and the backup flight system general purpose computer will be loaded.
Operations are also underway to prepare the orbiter for on- board cryogenic loading.
Later, orbiter navigation aids will be turned on and tested and the inertial measurement units will be activated. Also today, ground crews are making the final storage of mid- deck and flight deck supplies and payloads. They will perform microbial samplings of the flight crew's drinking water and check water levels in the crew waste management system. The STS-51 crew is scheduled to arrive at KSC at about 1 p.m. today. This is an eight hour hold lasting from 12 midnight to 8 a.m. Friday.