51.   But unlike the Pathfinder, which broadcast dramatic images from the Martian surface, the Japanese probe will conduct experiments from orbit high above the planet.

52.   First, Pathfinder must reach the martian surface.

53.   More than two years of geological surveying will follow in a quest for water on or just beneath the Martian surface.

54.   Rocks from Mars start their journey toward Earth when a meteorite from elsewhere slams into the Martian surface, scattering rocks into space at high speed.

55.   The inside of the rover must be as clean as the outside in case it crashes onto the Martian surface.

56.   The orbiting spacecraft turned on its thermal emission imaging system Tuesday morning, and gamma ray spectrometer instruments have begun collecting data on the composition of the Martian surface.

57.   The news came just hours before the next scheduled opportunity to deploy the rover by unfurling ramps so it could roll off the spacecraft and onto the martian surface.

58.   The spacecraft will map the chemicals and minerals in the Martian surface, partly in a search for frozen water.

59.   The small spacecraft landed on the Martian surface on the Fourth of July and has since released its small rolling probe, called Sojourner.

60.   The spacecraft is intended to map the chemical and elemental makeup of the Martian surface and hunt for water and hot springs that could indicate geothermal activity.