U.S. to renew Mars exploration with launch of orbiter Sept. 25

Nearly two decades after its automated Viking spacecraft made the first dramatic landings on the surface of Mars, the United States is preparing to renew its exploration of the Red Planet.

With an eye toward manned landings on Mars in the 21st century, the National Aeronautics and Space Administration is about to launch a sophisticated orbiter -- called Mars Observer -- that may yield much more about the planet's weather, terrain and geology.

Unlike the Viking landers -- which scooped up and analyzed Martian soil in a fruitless search for signs of life -- the Mars Observer will not carry out any biological investigations.

The launch is now set for Sept. 25. Once the space probe arrives at Mars in August 1993, it will enter a low orbit around the planet and will spend a full Martian year -- 687 days -- examining the planet with powerful on-board sensors and a high-resolution camera.

"No one instrument is going to make a discovery that's going to blow your roof off or make big press," said project scientist Arden Albee of the Jet Propulsion Laboratory in Pasadena, Calif.

Instead, Mars Observer should provide the sort of comprehensive data on Mars that will allow scientists to plan future missions.