JOHNSON SPACE CENTER - Shuttle commander Lee Archambault has used the thrusters on the space shuttle Discovery to maneuver the International Space Station 180 degrees from its normal attitude when an orbiter' is docked to it, adding drag to the two big spacecraft to lower their orbit out of the way of a threatening piece of space debris.
Archambault will leave the shuttle/station stack in the attitude normally used for docking and undocking,' with the orbiter forward instead of bringing up the rear in orbit. The tenuous atmosphere at the station altitude will supply enough drag to slow the two spacecraft by by about 1 foot per second over the three hours it will take to complete two orbits.
The maneuver , which started at 4:01 p.m. EDT, will lower the orbit enough to get the station and shuttle out of the way of a' 4-inch piece of an old Chinese rocket body that would otherwise pass too close to the docked spacecraft for comfort tomorrow. The projected conjunction is particularly worrisome because astronauts Joe Acaba and Richard Arnold are scheduled to go outside then for the third and final spacewalk of the STS-119/15A station assembly mission.
However, mission managers believe that by letting nature take its course in lowering the orbit, the Chinese' debris -- left over from' a 1999 launch -- won't pose a danger to the spacecraft or the spacewalkers.
Meanwhile, inside the ISS Expedition 18 commander Mike Fincke has been working all day to test the new urine distillation assembly Discovery took to orbit to replace a unit that' failed soon after it was installed last November. The unit worked well during dry run yesterday, but today Fincke and his crewmates have had trouble filling it with urine stored in the Russian section of the station.
After consultations with station controllers here, Fincke replaced the filter in the water recycling unit that includes the circular distiller, which must rotate to function in microgravity. That improved the flow, but the five-hour test still hasn't started.
(Via On Space.)