May 10, 2000. Copyright 2000. Graphic News. All rights reserved.

MISSION TO BOOST FALLING SPACE STATION

LONDON, May 10, Graphic News: NASA is making final preparations for a May 18 launch of the Space Shuttle Atlantis on an emergency mission to the International Space Station, which is slowly losing its orbit as it waits for an overdue Russian module.

Waiting in space for the seven Atlantis astronauts, the first components of the $60 billion Space Station are ÒfallingÓ at a rate of about 1-1/2 miles (2.4 km) a week because a long-overdue Russian service module, dubbed Zvezda, cannot be launched until summer. The slowly decaying orbit of the space station is something the stationÕs designers had not anticipated.

When the SunÕs surface erupts in solar flares Ð an 11-year cycle that is approaching its most intense period Ð it blasts huge magnetic clouds of high-energy atomic particles through space at more than a million miles per hour (1.5 million kilometres per hour). This intense Òsolar windÓ bombards the EarthÕs magnetic field, triggering geomagnetic storms and bright auroras in the upper atmosphere.

This current cycle of intense solar activity has caused EarthÕs atmosphere to expand, and although it remains thin where the space station orbits, there is now enough atmospheric drag on the station to accelerate the orbital decay experienced by all satellites. The stationÕs orbit has fallen to 227 miles (365 km) above EarthÕs surface.

When Atlantis docks with the fledgling space station, shuttle commander James Halsell and pilot Scott Horowitz will fire the shuttleÕs thrusters to boost the stationÕs orbit to 250 miles (400 km) above Earth, where it will wait for Zvezda, which carries enough fuel for the station to maintain that orbit.

The crew of six Americans and one Russian will also make repairs to the Russian-built Zarya power station and replace four of six batteries that have been overtaxed by months of operations without support from the large solar power array that will arrive with Zvezda.

Atlantis also carries in its cargo bay more than 2,000 lbs (907 kg) of supplies for future crews that will live aboard the station for months at a time.

Besides Halsell and Horowitz, the crew is made up of spacewalkers Jeffrey Williams and Jim Voss, mission specialists Mary Ellen Weber and Susan Helms, and Russian cosmonaut Yuri Usachev.

When Halsell and Horowitz take their seats for mission STS-101, they will be working with a new state-of-the-art cockpit design. NASAÕs Multifunction Electronic Display Subsystem (MEDS), otherwise known as a Òglass cockpit,Ó replaces obsolete instruments with 11 full-colour computer displays. The new cockpit weighs less, uses less electricity and enhances safety by providing multiple backup display functions. All of the Orbiters will eventually be outfitted with the new system, bringing the Space Shuttle cockpit up to date with technology now common in many commercial airliners.
/ENDS
Sources: NASA, Jet Propulsion Laboratory