ISS Status Report No. 02 - 2004

International Space Station Status Report #04-2
5:30 p.m. CST Friday, January 9, 2004
Expedition 8 Crew

Expedition 8 Commander Mike Foale celebrated his 47th birthday on Wednesday
this week while Flight Engineer Alexander Kaleri observed the Russian
Orthodox Christmas on Thursday as they both continued research work,
performed several maintenance activities and conducted troubleshooting
efforts to assist ground engineers analyzing a small decay in the Station
cabin's atmospheric pressure.

The pressure decay poses no threat to the crew's safety or to the continued
operation of the Station and its systems, but Russian and U.S. engineers are
conducting a thorough investigation of the decrease, which appears to have
begun about Dec. 22. The decline occurs at a rate so small, only a few
hundredths of a pound per square inch (psi) of pressure per day, that it is
difficult to detect.

This week, Foale and Kaleri checked a variety of valves and seals throughout
the Station using an ultrasonic leak detection system and found no leaks.
Today, Kaleri checked a Russian system, called Vozdukh, that removes carbon
dioxide from the cabin as well as several other Russian systems for leaks
and found none.

To continue the effort to diagnose the source of the pressure decay, flight
controllers in Russia and the U.S. plan to ask the crew to shut off portions
of the Station periodically in coming days. In the next few days, hatches
will be closed for periods ranging between 12-24 hours to seal off various
modules to check if any element within them could be the source of a leak.
Those modules may include the Progress cargo vehicle, the Pirs Docking
Compartment and Soyuz spacecraft, and the Quest airlock.

If those steps do not detect the source of the leak, then the crew may be
asked to move into the Russian living quarters module for several days and
shut hatches separating the Russian living quarters and other modules from
the rest of the station for several days. Those actions would likely not
take place any earlier than Wednesday. Engineers are continuing to work on
potential plans for those steps to diagnose the leak and to review the
number of hatches that would be closed at that time.

The decay in pressure over the past few weeks aboard the station has
amounted to a decrease from the normal pressure of 14.7 psi, a pressure
equivalent to sea level on Earth, to a pressure today of about 14 psi, a
pressure equivalent to the normal air pressure in Oklahoma City. The changes
in pressure do not present a concern for the health of the crew. Also,
plentiful supplies of air, oxygen and nitrogen, are aboard the station --
enough that the current rate of decay could be sustained for six months
without further supplies aboard if required. However, engineers are
confident they will identify and correct the source of the decay as they
continue the diagnostic work onboard.

Flight controllers may feed more nitrogen into the Station atmosphere late
Sunday or Monday to increase the overall air pressure and maintain the cabin
atmosphere in the optimal range for the operation of equipment aboard the
complex. Russian flight controllers also are continuing to evaluate the
possible replacement of parts of the Station's oxygen-generating Elektron
system. The Russian system generates oxygen by recycling wastewater aboard
the complex. It has failed, but spare parts are aboard that engineers are
confident can bring it back to full operation and they are developing plans
to perform that work possibly next week. While the Elektron failure is being
evaluated, the crew has used Solid Fuel Oxygen Generators, canisters that
are heated to produce oxygen, to replenish oxygen on the Station.

Despite the leak detection activities, engineers are not certain the
fluctuation and slight decline in pressure aboard the Station is the result
of a leak from the complex. Evaluations continue to determine if it instead
could result from or be significantly contributed to by troubleshooting and
intermittent Elektron operation, SFOG oxygen generation activities, recent
changes in temperature and sun angles, the accuracy of various pressure
measuring systems, or other factors.

Information on the crew's activities aboard the Space Station, future launch
dates, as well as Station sighting opportunities from anywhere on the Earth,
is available on the Internet at:

http://spaceflight.nasa.gov/

Details on Station science operations can be found on an Internet site
administered by the Payload Operations Center at NASA's Marshall Space
Flight Center in Huntsville, Ala., at:

http://scipoc.msfc.nasa.gov/

The next ISS status report will next week as events warrant.

-end-



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Jacques :-)

Editor: www.spacepatches.info