Hollow Mystery For Mars Rover (Hollow Grains)

The Mars rover Spirit has completed its first full set of scientific measurements with the instruments on its robotic arm, revealing mysterious hollow grains in the soil.

The one-metre arm used its microscope to take a close-up image of an undisturbed patch of soil next to the NASA rover. It shows mostly sand-sized particles, but with a large number of apparently hollow spheres or tubes. The image resolution is about 30 microns per pixel - about the width of a human hair.

Such grains were completely unexpected. But John Grotzinger, a geologist at the Massachusetts Institute of Technology, says they closely resemble formations he has seen in soils in the southwestern deserts of the US. "There are little tubes that build up by capillary action," he told New Scientist, as salty water evaporates from the nearly-dry soil.

The Martian grains must also be strong enough to withstand the region's strong winds and perpetual scouring by dust devils - tornado shaped vortexes that can tower to heights of kilometres.

The pressure and temperature conditions at Spirit's landing site, Gusev crater, are close to the triple point of water, Grotzinger says. This means any water present could change phase between solid, liquid and gas in response to small changes in conditions, and it is an area whose temperatures vary widely during the daily and seasonal cycles.

Pure liquid water cannot be stable at the site under present conditions, says Grotzinger. But a brine might be as the dissolved salts would change the freezing and boiling temperatures.

Other scientists suggested in 2003 that brines in the soil might explain other puzzling Martian features seen in images taken from orbit by Mars Global Surveyor. These are thousands of dark gully-like streaks seen on the walls of some craters and canyons.

But Grotzinger warns that it is far too early to rule out alternative explanations, such as dust that has been clumped together by electrostatic forces. This has previously been suggested to explain some crusty soil seen by the Pathfinder lander in 1997.

But, whatever is causing these unusual features, Grotzinger believes the rover's multiple spectrographic tools and trench-digging capabilities give it a very good chance of finding out.

Source: NASA/Jet Propulsion Laboratory
Date: 2004-01-19

Spirit Flexes Its Arm To Use Microscope On Mars' Soil

NASA's Spirit rover reached out with its versatile robotic arm early today and examined a patch of fine-grained martian soil with a microscope at the end of the arm.

This image taken by the front hazard-identification camera on the Mars Exploration Rover Spirit, shows the rover's robotic arm, or instrument deployment device. (NASA/JPL/US Geological Survey)

"We made our first use of the arm and took the first microscopic image of the surface of another planet," said Dr. Mark Adler, Spirit mission manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The rover's microscopic imager, one of four tools on a turret at the end of the arm, serves as the functional equivalent of a field geologist's hand lens for examining structural details of rocks and soils.

"I'm elated and relieved at how well things are going. We got some great images in our first day of using the microscopic imager on Mars," said Dr. Ken Herkenhoff of the U.S. Geological Survey Astrogeology Team, Flagstaff, Ariz. Herkenhoff is the lead scientist for the microscopic imagers on Spirit and on Spirit's twin Mars Exploration Rover, Opportunity.

The microscope can show features as small as the width of a human hair. While analysis of today's images from the instrument has barely begun, Herkenhoff said his first impression is that some of the tiny particles appear to be stuck together.

Before driving to a selected rock early next week, Spirit will rotate the turret of tools to use two spectrometer instruments this weekend on the same patch of soil examined by the microsope, said Jessica Collisson, mission flight director. The Mössbauer Spectrometer identifies types of iron-bearing minerals. The Alpha Particle X-ray Spectrometer identifies the elements in rocks and soils.

The rover's arm is about the same size as a human arm, with comparable shoulder, elbow and wrist joints. It is "one of the most dextrous and capable robotic devices ever flown in space," said JPL's Dr. Eric Baumgartner, lead engineer for the robotic arm, which also goes by the name "instrument deployment device."

"Best of all," Baumgartner said, "this robotic arm sits on a rover, and a rover is meant to rove. Spirit will take this arm and the tremendous science package along with it, and reach out to investigate the surface."

The wheels Spirit travels on provide other ways to examine Mars' soil. Details visible in images of the wheel tracks from the rover's first drive onto the soil give information about the soil's physical properties.

"Rover tracks are great," said Dr. Rob Sullivan of Cornell University, Ithaca, N.Y., a member of the science team for Spirit and Opportunity. "For one thing, they mean we're on the surface of Mars! We look at them for engineering reasons and for science reasons." The first tracks show that the wheels did not sink too deep for driving and that the soil has very small particles that provide a finely detailed imprint of the wheels, he said.

Opportunity, equipped identically to Spirit, will arrive at Mars Jan. 25 (Universal Time and EST; 9:05 p.m. Jan. 24, PST). The amount of dust in the atmosphere over Opportunity's planned landing site has been declining in recent days, said JPL's Dr. Joy Crisp, project scientist for the Mars Exploration Rover Project.

Today, Spirit completes its 13th martian day, or "sol", at its landing site in Gusev Crater. Each sol lasts 39 minutes and 35 seconds longer than an Earth day. The rover project's goal is for Spirit and Opportunity to explore the areas around their landing sites for clues in the rocks and the soil about whether the past environments there were ever watery and possibly suitable for sustaining life.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for NASA's Office of Space Science, Washington, D.C. Pictures and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

MARTIAN AIR FORCE DENIES STORIES OF UFO CRASH

Gusev Crater (MPI) - A spokesthing for Mars Air Force denounced as false rumors that an alien space craft crashed in the desert, outside of Ares Vallis on Saturday. Appearing at a press conference today, General Rgrmrmy The Lesser stated that "the object was, in fact, a harmless high-altitude weather balloon, not an alien spacecraft".

The story broke late Saturday night when a major stationed at nearby Ares Vallis Air Force Base contacted the Gusev Crater Daily Record with a story about a strange, balloon-shaped object which allegedly came down in the nearby desert, "bouncing" several times before coming to a stop, and "deflating in a sudden explosion of alien gases."

Minutes later, General Rgrmrmy The Lesser contacted the Daily Record telepathically to contradict the earlier report. General Rgrmrmy The Lesser stated that hysterical stories of a detachable vehicle roaming across the Martian desert were blatant fiction, provoked by incidences involving swamp gas. But the general public has been slow to accept the Air Force's explanation of recent events, preferring to speculate on the "other-worldly" nature of the crash debris. Conspiracy theorists have condemned Rgrmrmy's statements as evidence of "an obvious government cover-up," pointing out that Mars has no swamps. They point to the release of secret government memos detailing attempts to discredit reports of the landings by alien space craft. The memos discuss stategies to avoid troubles similar to those caused by the War of the Worlds radio program of years ago. The program, which featured a sensational story of gigantic oxygen breathing two-eyed invaders from Earth, sparked planet wide panic.

Local residents like Driv Rhodo, who lives in the area of the alleged landings, are even more sceptical. "I seen it with my own 5 eyes" claimed Rhodo last week. "I've lived here over 300 years, most of my adult life-form. Them things used to be few and far between but lately they come in every few years or so. The government wants to bury the truth but I can tell you what's real. The Earthlings are going to invade and the government is spending our hard earned tax dollars on press releases and denials instead of preparing for the battle to come."

A spokesthing denied any government involvement in the disappearance of Rhodo, who has not been seen since shortly after the interview, claiming "Any sentient being knows that a planet with the concentrations of water and oxygen found on Earth is a deadly and inhospitable environment for the formation of life, much less intelligent life. The fear and consternation caused by the unfounded and wild speculations of citizens like Rhodo are a traitorous disservice to the citizens of Mars."

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