Space Probe Lands on Mars
NASA
A mosaic image taken by the Spirit spacecraft shows a 360 degree panoramic view of the rover on the surface of Mars.
By JOHN NOBLE WILFORD
Published: January 4, 2004
Associated Press
NASA Administrator Sean O'Keefe and principal investigator Steve Squyres get a signal from the Mars Rover Spirit after it landed.
ASADENA, Calif., Jan. 3 — An American spacecraft, the robotic roving vehicle called Spirit, landed on Mars late Saturday night and radioed home that it was apparently safe and ready for three months' searching for signs of water in the planet's early history.
The first signals of success were intermittent and inconclusive as Spirit appeared to be bouncing and rolling over the surface. The suspense ended when flight controllers reported the reception of a "strong signal" from the rover's small antenna.
Chris Jones, director of planetary flight projects at the Jet Propulsion Laboratory, announced that deep-space antennas in Australia and California had "a solid lock" on radio signals from the 400-pound lander. Early indications, Mr. Jones said, were that the craft was resting upright after bouncing for more than a mile after touchdown.
Officials said this should make it easier for Spirit to shed its protective petals, raise a camera-laden mast and start taking pictures of its surroundings.
The landing about 11:25 p.m. Eastern time brought joy and relief at the Jet Propulsion Laboratory, in the foothills of the San Gabriel Mountains. Missions to Mars fail more often than they succeed, and the last American landing effort, in 1999, was an embarrassing failure.
Only this Christmas Eve, the British-built Beagle 2 tried to land and has not been heard from since, apparently a failure.
For days, officials of the American mission had gone out of their way to prepare the public, and perhaps themselves, not to be too optimistic. Even if the landing was successful, they said, a radio signal of the craft's status might not be received immediately. The silence need not be alarming, they cautioned, unless it continued through Sunday.
But data received during Spirit's entry into Martian atmosphere and descent to the surface indicated that the craft performed normally and was on target. The craft plunged into the upper atmosphere at a speed of 12,000 miles an hour. It was six minutes to touchdown 437 miles downrange at the 100-mile-wide Gusev crater, near the Martian equator.
In the landing sequence, Spirit turned its heat shield toward the angle of attack, a parachute opened, the heat shield was jettisoned, retrorockets fired — and then it was on Mars. The craft's aim had to be precise and in six crucial minutes of descent, the sequence of critical steps had to be taken on time. The flight was being controlled entirely by commands from spacecraft computers, with no time for human intervention.
The absence of a clear message heightened the anxiety that had been rising for days among flight controllers, scientists and officials of the National Aeronautics and Space Administration. They had said there was a strong chance that the craft would not be able to signal its status until sometime on Sunday. Much depended on being able to relay the signal through two spacecraft in an orbit of Mars, or to get a direct call through before Mars rotated out of communications range with Earth.
Concerns for the mission are one reason NASA sent two spacecraft to deliver rovers to the Martian surface to take advantage of the planet's current closeness to Earth. An identical rover, named Opportunity, is on its way to a scheduled landing at another site in three weeks.
The $800 million mission of the two spacecraft was designed to look for evidence in the rocks and sediments of liquid water on the surface in the Martian past. Ample signs of dry riverbeds and other erosion there have encouraged the search. Where there is or has been liquid water, astrobiologists think, there could have been life.
Explaining the rationale for current explorations of the planet, Dr. Edward J. Weiler, NASA's associate administrator for space science, said: "Mars is the closest place to look for life elsewhere, and the best place to look. Water is a key to life, and we know Mars has water, and that it was abundant there in the past."
But geologists on the project emphasized that the landers Spirit and Opportunity were not equipped to search for living or fossil organisms on Mars. Launched last June from Cape Canaveral, Fla., Spirit carries nine cameras, two spectrometers for analyzing rocks and soil, and a robotic arm for digging and scraping the surface. On landing, the rover is to photograph its environs in color as the first step in planning travels over the site. It should be capable of daily traverses of as much as 300 feet.
Gusev crater is thought to be an ancient basin that once held a lake. An examination of the rocks and sediments are expected to answer some questions about the warmer, wetter past of Mars, as geologists have hypothesized.
The rover was not expected to roll into action for another nine days, following testing and planning where it should begin looking for telltale signs of water in the Martian past.
