The Atlantis astronauts grew more space crystals Saturday, kept cameras poised to photograph lightning storms below and used a compact TV camera to beam down spectacular home movies showing the Gulf Coast and Baja Peninsula.

The astronauts also lowered the pressure in the crew cabin to test space helmets for space walks on future shuttle flights.A teleprinter message beamed up to the astronauts from mission control early in the day said the Magellan robot probe launched from Atlantis Thursday was "cruising toward Venus and all systems are nominal," NASA's word for perfect.

While the successful deployment of the $530 million spacecraft was the primary goal of the year's second shuttle flight, commander David Walker, 44, co-pilot Ronald Grabe, 43, Mary Cleave, 42, Mark Lee, 36, and Norman Thagard, 45, kept busy Friday and Saturday with a variety of relatively minor experiments.

Lee and Thagard both donned their space helmets in an hourlong test to determine how they would function if astronauts were called upon to make a space walk in future shuttle flights, and flight director Ron Dittemore said the test "worked just fine."

The astronauts also positioned a video camera in the shuttle's cargo bay to study lightning over Africa and tested a commercially available Sony 8mm "camcorder" video camera for future use in space.

Lee beamed down a remarkably clear home movie Saturday, a tour of Atlantis' crew module showing a crystal growth experiment, instrument-studded flight control panels and a variety of photographs and pennants on cabin walls.

Lee later broadcast spectacular television views of the Baja Peninsula, the Texas and Florida coastlines and views of Houston and the Kennedy Space Center in Florida as the shuttle soared overhead during its 32nd orbit.

For a second day in a row, Walker and Grabe also fired Atlantis' maneuvering jets over Maui to help an Air Force tracking station in Hawaii learn more about detecting objects in space.

Atlantis, making its fourth space flight, has sailed along with virtually no trouble whatsoever, other than a stuck valve in one maneuvering jet, the failure of a heater in a hydraulic system and problems Saturday with a hot water spigot in the ship's galley.

The crew tried to repair the spigot, but to no avail, and the astronauts stuck to using cold water only.

The crew is scheduled to wrap up the four-day mission with a landing Monday at 1:43 p.m. MDT at Edwards Air Force Base in California.