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ZL2VAL > ROVERS 03.01.05 11:26l 224 Lines 8816 Bytes #999 (0) @ WW
BID : E30600ZL2VAL
Read: GUEST
Subj: 1 year on Mars, & still going
Path: DB0FHN<DB0FOR<DB0SIF<DB0EA<DB0RES<ON0AR<ZL2BAU<ZL2AB
Sent: 050103/0745Z @:ZL2AB.#46.NZL.OC #:54661 [New Plymouth] FBB7.00g
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : ROVERS@WW
Jan 2, 10:23 PM
Mars rovers mark year of discovery
Ten lessons we learned from the missions
BY CHRIS KRIDLER
FLORIDA TODAY
Discoveries on Mars this year are edging scientists closer to learning
whether life existed there -- or still does. Today marks a year after
the landing of Spirit, the first of NASA's twin rovers. The product of a
rapidly developed $820 million mission that has paid off in exciting
extensions Spirit and Opportunity are still filling in details of a past
marked by volcanic explosions, asteroid impacts and, most important, water.
"It's entirely possible this kind of environment on Mars could have
generated the basic building blocks of genetics," said Steven Benner, a
University of Florida researcher who serves on a National Academies of
Science committee on the origins of life.
Meanwhile, Europe's Mars Express orbiter is delivering extraordinary
images of the red planet. Its observations of methane on Mars complement
those taken from the ground.
"What you have here is strong evidence, direct evidence, for the
existence of microbial life on Mars," said Mars Society President Robert
Zubrin, "or perhaps more accurately in Mars, since it's more likely
subsurface."
Such insights are among the 10 most important things learned on Mars
last year.
*1. Yes, there was water *
Photos snapped from orbit suggested dry lakes and riverbeds on Mars.
However, until NASA's Opportunity rover examined Eagle Crater, its
landing site in Meridiani Planum, there had been no proof.
At one time, there was a "habitable, watery environment at Meridiani
Planum," said rover principal investigator Steve Squyres of Cornell.
The evidence: round rocks dubbed "blueberries," which formed in water;
small holes formed by crystals that dissolved; rich sulfur content
attributed to water; cross-bedding or rock formations formed by flowing
water currents; and salt deposits typical of evaporation.
"I think that combination of discoveries, all of which we made at Eagle
Crater, constitutes our most significant finding," Squyres said.
*2. Life was possible *
Where there was water for long periods, the environment was habitable.
The bigger question is whether life could have developed in the first
place.
"It would have been a challenging environment for life in two ways,"
Squyres said. It was very acidic, and it was probably dry much of the
time, with water coming and going. "You shouldn't be thinking ocean," he
said. "You should be thinking salt flat or playa," a flat area at the
bottom of a desert basin.
Nonetheless, the rovers' discoveries offer both a promising target for
future missions and enticement to investigate whether life can arise in
such hostile environments.
Experiments suggest that deposits like those on Mars may create an
environment where the components of nucleic acids, the building blocks
of genetic material, are made and stabilized, Benner said.
"We cannot put the last piece together of that puzzle," he said. "We're
going to have to go back."
*3. Robots rock *
Spirit and Opportunity were supposed to last three months. Spirit is at
12 with Opportunity not far behind, highlighting the impressive
capabilities of robots.
"We're certainly going to get our money's worth out of them," project
manager Jim Erickson said. Their original cost of $820 million has been
supplemented with money to pay to keep operating them longer than planned.
As they come out of winter, they're getting more power than expected.
Dust on the solar panels has leveled off and even was cleaned off on
Opportunity, perhaps by wind or a dust devil.
Instead of traveling a third of a mile as expected, Spirit has rolled
about 2.5 miles.
"I never imagined that," Squyres said. "I simply never imagined anything
like that."
*4. Mobility is essential *
It's impossible to judge a whole planet by a few yards. Because they are
mobile, NASA's rovers have been able to build upon their initial
discoveries and make new ones.
For instance, even though 100-mile-wide Gusev Crater looks like an old
lake from orbit, Spirit initially found no obvious water evidence there,
just a lot of volcanic rock. But by traveling to the Columbia Hills,
it's seen abundant evidence of former ground water.
Wandering gives Earthlings perspective: They are not the center of the
universe. "It got us to some extent out of the view that you get from a
static lander that Mars is a place about the size of a parking lot of a
7-Eleven," Zubrin said.
Mobility also provides context. It will give Erickson the moment he most
anticipates, "when Spirit is able to get to the top and look down into
the valley from the other side of Husband Hill."
*5. People have limits *
The push to get the rovers launched from Cape Canaveral on time was
exhausting, and if it were standard procedure, there'd be a rebellion,
Erickson said.
After the landings, NASA's team had to work Mars days, which turned
their lives upside down. The extra 39 minutes they added to each day had
teams working around the clock in ever-shifting cycles.
"I think that three months is probably about the outside for running on
Mars time," he said. "Maybe if you had many more resources than we did,
you could have a cruise ship running around the world at 24 hours and 39
minutes per day."
*6. Methane mystery *
Europe's Mars Express orbiter has found water vapor concentrated in
three equatorial regions that correspond to where NASA's Odyssey saw a
layer of water ice below the surface.
Intriguingly, concentrations of methane overlap with the water vapor.
Though more analysis is needed, the discovery raises the question of
whether geothermal processes bring water vapor and methane to the
surface, or whether bacterial life might be a source of the methane.
"To me and to many of the researchers," Zubrin said, "the preponderance
of evidence indicates this is an artifact of biological activity."
*7. Complex weather *
The rovers see how dust scatters in the Martian atmosphere.
They track changes in clouds.
They study how the surface interacts with the atmosphere and how
shifting temperatures and winds help create weather.
Each rover has a mini-thermal emission spectrometer that can measure
temperatures of rocks or the sky.
At times, a rover mini-TES looked up while the thermal emission
spectrometer on NASA's Mars Global Surveyor looked down, creating an
unprecedented profile of a column of the atmosphere.
*8. Meteorites find match *
Bounce Rock may be like Martian rocks that hit Earth after they were
ejected by impacts on Mars.
Opportunity found that the volcanic rock has a strong similarity to some
meteorites discovered in Antarctica and other locations on Earth, giving
credence to the theory that they came from Mars.
If a future mission finds life or evidence of past life on Mars,
scientists may be able to determine whether microbial life evolved
independently there or traveled between Earth and Mars via ejected
chunks of rock, Zubrin said.
"There was a lot more of this stuff flying around 3 billion years ago,"
he said.
*9. Network works *
The rover mission proved that a communications network around Mars is a
reality. Mars Odyssey and Mars Global Surveyor relayed data from the
rovers at much higher rates than the robots alone could have handled.
Tests proved Mars Express could relay data, too.
*10. Cameras reveal all *
The rovers used multiple cameras, including the pan-cam or panoramic
camera, to capture images that can be appreciated in their highest
resolution only through the massive screen of an IMAX movie.
The movie is coming, but in the meantime, we've been fascinated by
landscapes, some in 3-D, that show craters with layers and dunes;
mysterious hills; and rock-strewn plains. Some individual images were
achieved with days of photography and even longer processing times.
Mars Express' high-resolution stereo camera offers stunning detail and
color from orbit, bringing valleys and volcanoes into captivating focus.
The images aren't just pretty: They bring Mars' past into focus for
scientists.
-=###=-
73, Alan
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