During the last two days, work has centered on monitoring Zarya's systems and uplinking a minor software change to the computer to rectify a time synchronization problem with the ground. All other systems are performing as expected with no major activities planned prior to Saturday when Endeavour arrives with the Unity connecting module to begin the assembly of the new station.
The few minor technical issues still under analysis pose no problems for the shuttle mission, or the International Space Station's future performance. The potential glitch with one of Zarya's six batteries remains under investigation and replacement parts are being carried aboard Endeavour that could be installed by the shuttle crew, if the decision is made by mission managers to do so. The battery is still usable, and even without repairs, is not expected to have an impact on station operations.
The crew plans to use Endeavour's cameras to document the outside of Zarya during the final phase of the rendezvous and after its capture by the shuttle's robot arm to evaluate the position of two small antennae that make up part of the Telerobotically Operated (TORU) manual docking system. Experts on the ground believe the antennae are fully deployed based on recent signal strength tests, but won't be able to confirm their theory until camera views are available from Endeavour. In any case, the shuttle mission and its three spacewalks will continue as planned and no additional work by spacewalkers Jerry Ross and Jim Newman is foreseen at this time.
Weather forecasters continue to predict a 60 percent chance against launching with low clouds and rain showers expected during the brief 5 minute launch window that opens at 3:59 a.m. EST.
During times when no operational systems checks are conducted, Zarya is placed into a slow spin to conserve fuel and maintain moderate temperatures on the spacecraft. It is presently circling the Earth once every 92 minutes in an orbit of 249 by 241 statute miles.