sjb (06/22/82)
The Columbia's electrical systems were turned on today in the final preparations for tomorrow's countdown commencement. Also today, crews installed a backup computer that will take over should any of the five main computers fail; other crews inspected the three main engines and the two SRB's. The countdown is scheduled to begin at T-90 hours (with about a day's worth of holds built in) tomorrow at 1700 EDT aiming for a 1100 EDT launch on Sunday.