Pathfinder data shows Mars may have crust, core
Spacecraft talking to Earth again
October 8, 1997
Web posted at: 8:34 p.m. EDT (0034 GMT)
PASADENA, California (CNN) -- Data collected by Mars Pathfinder shows that the red planet, like Earth, may have a crust, a mantle and an iron core -- evidence that the planet may have once been warm.
That hypothesis, reached by scientists at NASA's Jet Propulsion Laboratory, is based on a comparison of changes in radio signals from Pathfinder as Mars spins on its axis. It would contradict the belief that Mars is merely a solid, inert ball of rock, like Earth's moon.
Perhaps more importantly, if Mars had enough heat to form the distinctive layers, it would add more weight to theories that the planet may once have been warm and wet enough for life to form. However, scientists still remain a long way from proving that there was once water on Mars.
JPL scientist William Folkner said scientists do not yet know whether Mars' iron core is solid or molten like the Earth's.
Molten cores are rare among the planets in Earth's solar system. Only two planets, Earth and Mercury, are known to have a liquid core, which, on Earth, is what creates a magnetic field.
Pathfinder calling home again
JPL officials also announced that Mars Pathfinder's main transmitter started talking to Earth again Tuesday after more than a week of silence.
"We were nine days in kind of limbo. We'd gotten signals from the auxiliary transmitter, but we weren't consistently getting them," Pathfinder project manager Brian Muirhead said.
Now that Pathfinder is transmitting to Earth again, mission scientists are planning to do a full run of the spacecraft's engineering data to check the instruments on board. They said it will be a few more days before new scientific data and images from the red planet will be gathered.
Both Pathfinder and its little rover, Sojourner, have outlived the life span for which they were designed -- seven days for the rover and 30 for the lander.
Panorama sheds light on 'problem of the pebbles'
Summing up their findings thus far about Pathfinder, which landed on Mars July 4, the scientists agreed that the data gathered by the unmanned probe appeared to answer quite a few questions about Mars -- but that more time would be needed for a more complete assessment of the ongoing mission.
With just over 80 percent of the landing site "super panorama" picture complete, JPL geologists said that they now have clear images that may shed light on what has been described as the "problem of the pebbles."
Geologists are evaluating several theories that would explain the roundish, pebble-shaped rocks of various sizes found on Mars' surface. The present-day shape of the rocks could have been formed by catastrophic floods or glaciers that transported them, according to the geologists.
Scientists also said that some pictures also showed small dune formations of various shapes. These dunes -- given names such as Mermaid Dune or Jenkins Dune -- suggest the existence of dust on Mars.
Some of the dunes were believed to measure about 2 1/2 meters (8 feet) in length and about 30 cm (1 foot) in height.
With water on Mars, if it once existed, now long gone, wind seems to be an important force shaping the surface of the red planet, the scientists said.