Wednesday March 10 1:51 AM ET

Spacecraft Begins Mapping of Mars

By JOHN ANTCZAK Associated Press Writer

LOS ANGELES (AP) - The Mars Global Surveyor has finally begun mapping the red planet, turning an array of instruments on Earth's dusty neighbor a year later than originally planned.

``All our instruments are on now,'' flight operations manager Joseph Beerer said Tuesday at NASA's Jet Propulsion Laboratory in Pasadena.

The spacecraft, which started its primary mission Monday afternoon, has a camera to make wide- and narrow-angle images of Mars, and a laser altimeter to measure surface features by bouncing pulses of light off the planet.

It also carries a spectrometer to scan for heat transferred from the planet to the atmosphere and to map mineral composition, and a magnetometer to gather data that can be used to understand the interior of Mars.

The spacecraft has already delivered a preview of the science portion of its mission. It has sent back detailed images of such features as 16-mile-high Olympus Mons and the planet's ancient water and lava flows.

The surveyor was launched in November 1996 and went into orbit around Mars in September 1997. It was supposed to begin its primary mapping mission a year ago after using a process called aerobraking to tighten its orbit.

Mapping had to be put off for a year because a damping mechanism on one of its two solar panels did not operate properly when it was deployed and controllers decided to avoid stressing the part by a gradual aerobraking.

The satellite is in a two-hour orbit. Instruments will gather data during nine of each day's orbits and then the spacecraft will be turned to point its antenna at Earth to transmit that data during three orbits, Beerer said.