Flight controllers for NASA's Mars Global Surveyor mission are continuing to work toward isolating what caused a hinge on the spacecraft's high-gain telecommunications antenna to stop moving last week.

This afternoon, engineers received the results of a test they conducted earlier in the day that moved the hinge one-half of a degree from side to side. The information from the spacecraft shows that the hinge moves freely in one direction, but it's motion appears to be obstructed in the opposite direction.

The tests are designed to help engineers determine if the obstruction is internal to the motor mechanism, or external, such as a thermal blanket or cable obstruction. Flight controllers continue to analyze the test results and will send additional commands to the spacecraft tomorrow that will attempt to move the hinge a little bit more -- one full degree -- in each direction.

The spacecraft remains in good health and the science instruments are turned off while engineers continue to define the hinge.

There are two hinges at the end of the boom that connect to the high-gain antenna. One hinge, called the azimuth hinge, moves the antenna from side to side; the other hinge, called the elevation hinge, moves the antenna up and down. The azimuth hinge stopped moving midway between its "parked" position and the position its in when it is transmitting data to Earth.