PASADENA, July 10: The Mars Rover carefully sidled up to another newly discovered ``rock star'', nosing close to a boulder nicknamed ``Yogi'' that scientists hope will deliver more clues about the red planet.

``We are looking for different rocks so we can get a better idea of Mars' total composition,'' said mission scientist Matthew Golombek at NASA'S jet propulsion laboratory here.

``We have lots of different rocks on earth and we would expect to find the same thing on Mars,'' he said.

``Yogi,'' named after the cartoon character Yogi Bear because of what some scientists call its bear-like appearance, will be the second Martian rock that the little six-wheeled buggy has probed following the Pathfinder spacecraft's landing in the Ares Vallis basin of Mars last Friday.

Its first target, the pockmarked-looking ``Barnacle Bill'', yielded a stream of information which surprised scientists by showing that Mars, far from being alien, is instead a lot like earth.

In the quest to expand the available data, the Rover will also be sent to two other nearby rocks, ``Casper'' and ``Scoobie Doo'' also dubbed after cartoon characters -- to examine them with its alpha proton X-ray spectrometer.

The Sojourner had been originally scheduled to scan ``Yogi'' shortly after its landing, but photographs from the lander craft showed the front of the rock sitting in a hollow, perhaps formed when it was deposited there, either by a flood or being blasted from a nearby volcanic eruption millions or billions of years ago.

This, explained Golombek at a media briefing, could mean that if the Rover was to venture to that part of the rock it might slide into the hollow and bump its solar panels against the rock, depriving its batteries of valuable energy from the sun.

So the Sojourner spent much of Tuesday taking high resolution, close-up pictures of ``Yogi'' to determine where it should place its spectrometer against the rock, where it would bombard the surface with protons.The device, which explores the chemical make-up of rocks by measuring the changes in protons as they bounce back, is intended to determine the rock's composition.

Copyright © 1997 Indian Express Newspapers (Bombay) Ltd.