Continued transfer of hardware and supplies to and from the Mir space station remains the prime order of business today as STS-89 enters its second full day of joint docked operations. The crew was awakened at 5:48 a.m. CST to the tune "Singer from Down Under" by performer Slim Dusty in honor of Australia Day and Australian-born astronaut Andy Thomas.
Flight controllers labored overnight to delete lower priority items from the Endeavour crew’s workload to make up for lost sleep due to an attitude control management issue. Late Sunday, an erroneous sensor reading showed a leak on Endeavour’s reaction control system jet L5D. It was shortly determined that the sensor showing the leak was faulty and onboard monitoring of the affected jet could be managed with a software change. That change requires ground testing and approval before it is sent to the shuttle’s computers and will be tested this morning in the Johnson Space Center’s Shuttle Avionics Integration Laboratory (SAIL). Following the sensor failure, Mission Control asked Russian controllers to let Mir maintain attitude control for the joined spacecraft. Transfer of control was done late Sunday, but the work consumed some of the crew’s scheduled sleep time.
Not long after the handover of control, however, Russian engineers monitoring Mir determined that the space station was low on thruster fuel in its outboard "boom" thrusters. Flight controllers in the U.S. and Russia worked together and decided that, with good communications contact, Mission Control could watch Endeavour’s thruster and the Shuttle could resume control. The ground awakened Pilot Joe Edwards about 1:15 a.m. CST. Edwards and commander Terry Wilcutt woke the Mir crew and the attitude control handover back to Endeavour was accomplished in a few minutes.
To compensate for keeping the crew up late, the planning team in Mission Control added an hour to the crew’s sleep period and worked to lighten the workload for flight day 5.
Also on Sunday, astronauts Andy Thomas and David Wolf exchanged their Soyuz seat liners, equipping Thomas for the start of his extended stay in space. Thomas had some difficulty with his Sokol pressure suit during the transition and checkout, noting that it was too small. He was able to don Wolf’s suit, but found the arms to be too long. Engineers in the U.S. and Russia will look at the problem today in an effort to properly size one of the suits to fit.
By the end of flight day 4, 47 percent of the supply and equipment transfers had been completed, totaling 4,107 pounds.
The next STS-89 status report will be issued Monday evening at 6 p.m. Central time.
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