Thereafter, X-SAR controllers continued a deliberate, step-by-step check of the instrument, and successfully bounced X-band radar pulses off the Earth and recorded data.

As of Sunday morning, 10 April 1994, the radar laboratory had taken data readings on more than 40 targets including Howland, Maine; Macquarie Island; the Black Sea; Matera, Italy; and the Strait of Gibraltar.

Observation sites for Sunday afternoon included Gippsland, Australia; Sable Island; Toronto, Ontario, Canada; Bermuda; Bighorn Basin, Wyoming; Chung Li, China; and Mammoth Mountain, California.

Sunday evening's supersite observations by SIR-C and X-SAR focused on the interaction of plants and animals in the ecology of the forests of Raco, Michigan; hydrologic cycles around Bebedouro, Brazil; tectonic plate activity around the Galapagos Islands in the South Pacific; and the transfer of heat through wave energy in the Southern Ocean.

Crew members reported good earth observation photography opportunities over the Northeast Pacific Ocean and the frozen lakes of the Raco supersite area, as well as fires in the Sierra Madre mountains of Mexico.

On flight day two, the Red Team crew of Commander Gutierrez, Pilot Chilton and Linda M. Godwin began its sleep shift about 5 pm Central time, to awaken at 2 am The Blue Team crew members, Jay Apt, Michael R. Clifford and Thomas D. Jones, awakened about 4 pm to begin their third flight day on orbit, and would go to bed about 5 am As of Monday, 11 April 1994, 6:30 am Central time, three real-time radar images were downlinked from Endeavour overnight.

A view of the Sahara Desert in Algeria, one of the geology sites, was taken to help scientists map surface and subsurface structures, including drainage patterns.

Thomas D. Jones gave scientists real-time observations of thunderstorms over Taiwan, the Philippines and New Guinea to augment data being gathered by the (MAPS) experiment.

The MAPS project's Vickie Connors reported to Endeavour's Red Team that there was good correlation between what the instruments on board were reading compared to data gathered on the ground.

During this shift, live X-SAR moving images were downlinked of the area surrounding Sarobetsu, Japan, one of the high-priority calibration sites for the X-band antenna.

Ground investigators were taking simultaneous measurements of the ecological test site, looking for soil and vegetation information during the dry season of the tropical forest there.

Godwin reported that the crew had a cloud-free opportunity to photography Chickasha, Oklahoma, one of the 19 "supersites," and that they had seen sea ice along the coast of the Kamchatka Peninsula of Russia.

At 6 pm CDT, Chilton explained to the public how a vast network of ground scientists and students camped in the field at many of the worldwide sites assist with the radar observations, and Godwin answered questions supplied by CNN viewers around the world.

On Saturday, 16 April 1994, at about 11:30 pm and again at 1:15 am central time, Jay Apt used Endeavour's Shuttle Amateur Radio to talk with fellow astronauts Norm Thagard and Bonnie Dunbar and two Russian cosmonauts at the Star City training center outside Moscow.

The Blue Team—Jay Apt, Rich Clifford and Tom Jones—reported several visual observations including fires burning in Africa and a line of thunderstorms over northeastern Brazil.

Payloads scientists asked the crew to add the Rügen Island, off Germany's northern coastline in the Baltic Sea, to their list of Earth observations photography.

The annoyance that was present since the first day of the flight has been laid to rest with the successful in-flight maintenance procedure to get rid of air bubbles in the crew's water supply.

On Sunday, 17, 12 April:30 pm Central time, Endeavour's flight control surfaces and thruster jets were checked out to ensure they were in good working order for planned landing at the Kennedy Space Center.

On this day, two weeks after Easter Sunday (in the Gregorian Calendar) three of the astronauts - Gutierrez, Chilton and Jones - took part in a Roman Catholic service of Holy Communion.

The weather forecast was favorable for a landing in Florida, although flight controllers were watching a possibility of low clouds and a slight chance of showers in the area.