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Update: 01-106

INTERNATIONAL SPACE STATION
Expedition Two Science Operations

Status Report for Friday, April 6, 2001

Flight Engineer Susan Helms conducted additional tests of a space structures experiment Thursday.

Tests of the Middeck Active Control Experiment 2 begun during Expedition One are continuing with the Expedition Two crew.  These tests will continue until the experiment returns to Earth along with the Expedition Two crew on the 7A.1 Space Shuttle mission planned for July.

MACE studies the effects of vibrations on moving structures in space.  Data from the experiment can help engineers design strong, lightweight, low-cost structures.

The MACE platform is 60 inches – or 152 centimeters – long, including four struts and five nodes.  Helms, who began MACE tests on Tuesday, used a handheld control unit to send pre-programmed commands to the computer on the MACE structure.  These commands caused gimbals and reaction wheels attached to one side of the structure to vibrate.  A support module detected the vibrations and attempted to damp them by activating gimbals and wheels on the other side of the platform.

All data from the experiments are stored on removable hard drives for future analysis by scientists on Earth.  MACE involves science teams from the Air Force Research Laboratory at Kirtland Air Force Base in New Mexico, and the Massachusetts Institute of Technology at Cambridge.

Also Thursday, Flight Engineer Jim Voss completed maintenance on the Bonner Ball Neutron Detector.  Bonner Ball is one of three radiation-monitoring experiments on board being used to characterize the station’s radiation environment and the potential effects on humans.  Voss replaced a hard drive unit with a full memory with a new hard drive with fresh memory.

Editor’s Note: The Payload Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., manages all science research experiments aboard the International Space Station.  The center is also home for coordination of the mission-planning work of a variety of international sources, all science payload deliveries and retrieval, and payload training and payload safety programs for the Station crew and all ground personnel.