Operations onboard Endeavour continued without interruption, even without the availability of a small nitrogen thruster on the end of the extended boom.

By midday, about 24 million square miles had been mapped once, and 9 million square miles twice. That�s more than half the planned coverage for the mission.

Mission scientists continue to express delight with the "quick-look" data seen so far. SRTM project scientist Dr. Michael Kobrick notes that Endeavour is mapping 100,000 square kilometers every minute, and that after only three days of flight, the mission has tripled the world�s supply of digital terrain elevation data.

The low-resolution images processed so far show many topographic features that until now have been difficult to detect on the best maps in existence today.

A continuing problem with a small nitrogen thruster on the end of the 200-foot-long mast has had no impact on mapping operations or data quality. Both radar systems -- C-band and X-band -- continue to perform flawlessly.

Flight controllers are continuing to troubleshoot the problem with the thruster, which helps control the mast�s attitude. This function currently is being performed by Endeavour�s reaction control system. Mission managers are implementing propellant conservation measures and hope to meet the full nine-day science objective. The mast continues to provide an extremely stable platform for the mapping operations.

As their workday concluded, Blue Team members Dom Gorie, Janice Voss and Mamoru Mohri spent a few minutes on Endeavour�s flight deck discussing various mission activities.

The Blue Team turned in shortly after 2 p.m., with a wake-up call set for 10:14 tonight. The Red Team�s Kevin Kregel, Janet Kavandi and Gerhard Thiele was awakened a few minutes after 10 a.m. to continue mapping operations.

S99-E-5256 (13 February 2000) --- Astronauts Janet L. Kavandi and Gerhard P.J. Thiele pose with a globe and a shuttle model, equipped with the SRTM payload, on Endeavour's flight deck.

As of this morning, 525 images had been taken by students using the EarthKam, which allows photos of Earth to be taken using a camera on the shuttle. So far, 20 of the 84 schools participating in the program have requested and received photos.

All of Endeavour�s systems are functioning normally as it circles the Earth every 90 minutes at an altitude of about 150 miles. The next STS-99 mission status report from Johnson Space Center will be issued at 6 a.m. Tuesday, or as events warrant.