From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Aug 22 2003 - 08:07:41 PDT
Good news for the exploration of the planet Mars and the expansion of human knowledge: Both of the Mars Exploration Rovers (MER) are now on their way to the Red Planet, carrying a suite of scientific instruments designed and built under the guidance of Cornell University.
"The launch [of the rovers] was the second most difficult part of this mission," said Jonathan Joseph, the main programmer at Cornell overseeing the software designed to analyze the images of the Red Planet's surface from the panoramic camera, or Pancam. "The most difficult part [of the mission] will be the landings on Mars."
On June 8, the two "robot field geologists," as the Athena science package team has referred to the Mars rovers, were officially named Spirit and Opportunity - names submitted by contest-winner Sofi Collis, 9, of Scottsdale, Arizona. Her name submissions were selected from over 10,000 others in a contest sponsored by The Planetary Society and LEGO.
Two days after the naming, on June 10, following a number of weather and technical delays, the newly named rover Spirit climbed into the skies above Cape Canaveral, Florida, aboard a Delta 2 rocket.
Spirit's sister rover, Opportunity, originally set for launch on June 25, found itself remaining on Earth while summer storms and problems with the new Delta 2 Heavy booster left everyone wondering if the rover would be on its way to Mars before the celestial deadline of July 15. After that, Opportunity would have had to wait two years until Earth and the Red Planet aligned properly in their solar orbits again to allow a launch.
Everything was resolved with time to spare and Opportunity joined its twin rover in the heavens on the evening of July 7.
During the rovers' seven-month cruise through interplanetary space, the Pancam will be tested twice in space. Though there is little to see in the unlit confines of their protective shells, Athena team members will take images with the digital camera to get back "dark current", as Joseph called it, to calibrate the instrument and remove any "bad" pixels before the rovers arrive at Mars in January of 2004.
The primary scientific goal of MER is to find evidence that liquid water once flowed across the surface of the Red Planet. While the rovers are not specifically designed to look for actual Martian organisms, either fossilized or alive, discovering traces of past water activity from the clues in the native rocks and soil will strongly support the possibility that life once evolved on the Red Planet and, by consequence, on other worlds beyond Earth.
After long and extensive studies of thousand of images of the Martian surface taken by the currently orbiting Mars Global Surveyor and Mars Odyssey probes, mission scientists chose two locations that seemed both scientifically promising and reasonably safe for landing the precious rovers.
Spirit is aimed for Gusev Crater, a 95-mile-wide feature just south of the Red Planet's equator. The fascinating aspect of Gusev is the long valley named Ma'adim Vallis (Ma'adim is the Hebrew word for Mars) that connects with the crater. Scientists believe this valley was carved out by running water which may have flowed into Gusev, turning the impact basin into a lakebed. There may be sediments preserved at the bottom of the crater that can tell scientists the history of this region.
Opportunity will arrive at Mars three weeks after Spirit and land more than 6,000 miles from its robot twin on the other side of the planet, at a place called Meridiani Planum. One of the flattest and smoothest places on this alien world, Meridiani Planum also has an abundance of an iron oxide mineral called gray hematite. On Earth this hematite is usually found in association with liquid water. Scientists will use Opportunity to see if this holds true for Mars.
Athena team members will not be idle while the Mars rovers spend over half a year in space heading to their destination. The engineers, researchers, and scientists will be continually testing and retesting the software and hardware of the rovers, both the ones in space and several realistic models on Earth. They will also be practicing how to handle their automated geologists on the mysterious Martian surface.
Once the rovers are on Mars, their time to conduct science and return the valuable data to their creators will be limited by how the long the robots can be kept functioning. Even if the machines are not rendered useless by some unforeseen accident, dust from the planet's atmosphere will settle and accumulate on the rovers' solar panels. Eventually the probes will be cut off from their primary power source, the Sun.
When Spirit and Opportunity arrive next January, they will not be alone. The European Space Agency (ESA) and Japan have sent their own emissaries to the Red Planet. This will be the largest group of spacecraft heading to Mars at one time since the early 1970s.
The European contribution, launched from Russia on June 2, is a combined orbiter and lander mission. When Mars Express begins circling the Red Planet this December, it will release a probe named Beagle 2 that will touch down on Isidis Planitia on Christmas Day. While the orbiter uses radar to scan for underground water, the lander will conduct the first direct search for life on Mars since Viking in 1976.
Japan's first Mars probe, named Nozomi (meaning Hope), is scheduled to go into Mars orbit around the time the rovers reach the planet, where it will study the upper atmosphere of the fourth planet from the Sun.
For more information on MER and the Athena science package, visit athena.cornell.edu.
By Larry Klaes
The Ithaca Times - August 20, 2003
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