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09 January 2004

NASA scores big

by Forrest M. Mims III

Soon after the dawn of the space age in 1957, sending probes to Mars became a high priority objective. Following a series of spectacular failures by the USSR and the US, in 1965 NASA's Mariner 4 became the first spacecraft to fly by Mars and send back close-up photographs of the red planet.

An artist's conception shows the Mars Exploration Rover approaching a rock with its instrumented arm. TV cameras are atop the vertical mast. Courtesy NASA Jet Propulsion Laboratory. Click image to enlarge.

In 1971 the USSR orbited two spacecraft around Mars. Both craft sent small probes to the surface. One crashed onto the planet. The second landed safely, but its signal was soon lost.

In 1975, NASA successfully landed two Voyager spacecraft on Mars. For more than five years, they sent back photographs, weather reports and scientific data.

In 1997, NASA's Mars Pathfinder bounced onto the surface of Mars inside a protective covering of air bags. The landing craft carried Sojourner, a 6-wheeled robot not much bigger than a radio-controlled toy car. Sojourner and its base station sent back more than 16,000 photographs.

The Pathfinder success was followed by disaster in September and December 1999, when NASA lost two expensive Mars probes.

As the world now knows, late Saturday night NASA returned to Mars with the Mars Exploration Rover, the biggest and most sophisticated robotic rover yet. The six-wheeled vehicle is the size of a golf cart and weighs nearly 400 pounds.

As the landing craft named Spirit parachuted down to the martian desert, gas balloons surrounding the lander and the rover were inflated. These cushioned the lander, which bounced on the surface before eventually coming to a stop.

While this was happening, the team of scientists and engineers at NASA's Jet Propulsion Laboratory in Pasadena, California, listened to musical tones sent by the lander that signaled various steps in the landing process. When the landing was confirmed, they erupted into cheers and applause.

Within hours of touching down, a camera on the rover peeked out from its perch and began sending the first digital images of its new home. They show a sandy desert strewn with rocks that seem to be smaller than those at the pathfinder landing site in 1997.

Many steps remain before the rover will be sent on its 90 day mission to explore Mars. During this time it will travel around 100 feet each martian day.

Cameras on the rover will record the sky, the horizon and the area immediately around the vehicle. Sophisticated scientific instruments will analyze soil and rocks.

The rover even carries a digital microscope for close-up views of soil and rock. It has a powerful grinder that can cut through layers of surface rock to expose unweathered rock below.

In only three weeks, a second rover is scheduled to land on Mars. Rover 2 is an exact twin of Rover 1, and it will explore the opposite side of the red planet. You can stay up to date with the current Mars missions by visiting www.nasa.gov and many related links. I'll see you there.

Forrest M. Mims III and his science are featured online at www.forrestmims.org.