1 p.m. CST, Friday, March 3, 2006
homestretch of a half-year mission, International Space Station
Commander Bill McArthur and Flight Engineer Valery Tokarev
monitored the departure of one of two Russian cargo ships
Filled with trash and items no longer needed, the Progress 19
vehicle undocked from the Zvezda living quarters module at 5:06
a.m. EST. Three hours later, Russian flight controllers commanded
its engines to fire to put it on course to plunge into the
atmosphere and burn up over the Pacific Ocean. The cargo ship was
docked to the station since September 2005.
The station's Progress 20 cargo vessel, which arrived in
December 2005, remains attached to the Pirs Docking
Also this week, McArthur replaced the trace contaminant control
system in the Destiny Laboratory. The system removes impurities
from the cabin air. It experienced a slightly degraded performance
over the past few months, but is operating normally.
On Monday, McArthur will attempt to reconnect and activate the
major constituent analyzer in Destiny. It is a mass spectrometer
that measures compounds in the station's atmosphere. Efforts to
activate the system two weeks ago were unsuccessful due to what is
believed to be damaged or bent electrical connectors.
Once the device is activated, plans can resume for a crew
“campout” in the Quest Airlock to test streamlined
spacewalk preparation procedures. The new procedures will shorten
the time needed to cleanse nitrogen from spacewalkers' bodies to
prevent decompression sickness. For the test, the crew will spend
the night in Quest at a reduced pressure, lessening the time needed
to breathe pure oxygen in advance of a spacewalk.
The “campout” technique will be used for the first
time for spacewalks on the STS-115 shuttle mission later this year.
If the major constituent analyzer is successfully activated, the
campout test will be scheduled around March 23.
McArthur continued preparations for the arrival of the next
shuttle mission. Discovery is targeted for launch no earlier than
May on that flight, designated STS-121. This week, McArthur put
unneeded items in racks earmarked for return to Earth aboard
McArthur and Tokarev will soon begin preparations for a short
trip from the station. Managers have agreed on a tentative schedule
on March 20 for the crew to relocate their Soyuz TMA-7 spacecraft
from the Earth-facing docking port of the Zarya module to the aft
docking port of Zvezda. McArthur and Tokarev will undock from Zarya
and conduct a 37-minute flight to re-dock at Zvezda. The move will
clear the Zarya port for the April 1 arrival of the Soyuz carrying
the next station crew, Expedition 13.
Expedition 13 is commanded by Pavel Vinogradov. Jeff Williams is
NASA Flight Engineer. Brazilian astronaut Marcos Pontes will fly
with them to the station for a short stay, returning to Earth a
week later with McArthur and Tokarev.
Next week, McArthur will brush up on his robotics skills,
operating the Canadarm2 for engineering tests. The arm also will be
remotely commanded by flight controllers in Houston. They will
operate the arm to survey one of two integrated umbilical assembly
mechanisms on the mobile transporter rail car. The assembly's
cutting blade system malfunctioned Dec. 16, severing one of two
umbilicals on the transporter. The assembly will be replaced on the
second of the three spacewalks planned for Discovery's mission.
Controllers also will use the arm to survey a vent port for the
carbon dioxide removal assembly on the Destiny Laboratory.