Monday, July 25, 2011
Nasa has also announced details of plans to determine if Mars has or ever had the ingredients for life. A robotic science laboratory, being prepared for a November 25 launch, will land in August 2012 near a mountain in a crater on the planet most like Earth in the solar system.
Read more: http://www.dailymail.co.uk/sciencetech/article-2018477/Nasa-ordered-astronauts-asteroid-15-years.html#ixzz1T8Iuhs6r
The announcement came after the final curtain fell on Nasa's 30-year-old space shuttle programme with Thursday's landing of Atlantis at the Kennedy Space Center.
A detailed blueprint of Nasa's follow-on space exploration strategy is still pending and many Americans fear the demise of the shuttle program means the U.S. is relinquishing its leadership in space. President Barack Obama has said the objective is to build new spaceships that can travel beyond the shuttle's near-Earth orbit and eventually send astronauts to asteroids, Mars and other destinations in deep space.
At a Cape Canaveral briefing on Wednesday, Nasa officials will discuss preparations for the agency's upcoming Juno mission to Jupiter.
The unmanned spacecraft, set for launch in August, is expected to reach Jupiter's orbit in July 2016 and should further understanding of the solar system's beginnings by revealing the origin and evolution of its largest planet.
Among the most sophisticated probes in the offing, the plutonium-powered roving Mars Science Lab, nicknamed Curiosity, is being prepared for launch in November.
Twice as long and five times heavier than previous Mars rovers, Curiosity packs ten science instruments, including two for on-site chemical analysis of pulverized rock.
With it, scientists hope to learn if Mars has or ever had the organics necessary for life - at least life as it appears on Earth.
Scientists spent five years mulling 60 possible landing sites before narrowing the list to four: Eberwalde Crater, Mawrth Vallis, Holden Crater and - the winner - Gale Crater, which sports a stunning three mile-high mountain of rocks rising from the crater floor. That's about twice the height of the stack of rocks exposed in the Grand Canyon.
Analysis from Mars-orbiting spacecraft shows the base of Gale Crater's mountain includes both clays and sulphate salts, the only site among the four finalists with both types of materials available.
Scientists do not know how the mountain formed, but it may be the eroded remnant of sediment that once completely filled the crater.
Though Curiosity's mission is scheduled to last two years, scientists hope the rover will live past its warranty.
One of a pair of Mars rovers that arrived for concurrent three-month surveys in January 2004 is still working. Its twin succumbed to the harsh Martian environment only last year.
They returned evidence that Mars was once far wetter and warmer than the dry, cold desert that exists today.
Sunday, July 24, 2011
Scientists who study the Red Planet say they whole-heartedly approve of the choice of Gale Crater as the landing site for NASA's next Mars rover.
NASA's next Mars rover will land at the foot of a layered mountain inside the planet’s Gale Crater.
CREDIT: NASA/Jet Propulsion Laboratory
The space agency announced the decision to go with Gale today (July 22), after a five-year process that originally considered about 60 possible sites. NASA narrowed the list down to four choices in 2008, then revealed last month that it was deciding between two finalists: Gale and another crater called Eberswalde.
Gale is 96 miles (154 kilometers) wide, and a 3-mile-high (5-km) mountain rises from its center. The crater also harbors clays and sulfate salts, signs that liquid water flowed in the area long ago.
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The car-size Curiosity rover— the centerpiece of NASA's $2.5 billion Mars Science Laboratory (MSL) mission — will cruise around Gale beginning in August 2012. Its main mission is to assess whether the crater is, or ever was, capable of supporting microbial life. [Mars Explored: Landers and Rovers Since 1971 (Infographic)]
Via email, SPACE.com asked several scientists with extensive experience studying Mars, and/or the prospect of Martian life, what they thought about NASA's choice. By and large, they were excited about Gale and the potential of Curiosity's mission:
Maria Zuber (geophysicist at MIT in Cambridge, Mass.): To be honest, I am thrilled with the decision to land in Gale Crater.
Geologically, the site is complex. But given the mission objectives, that is a good thing, as it contains much of what one would like to observe and measure to assess habitability and biological potential, and how these may have changed over time.
The Curiosity payload and the ruggedness of the rover are well suited to address the science objectives at this site.
Mark Lemmon (planetary and atmospheric scientist at Texas A&M University in College Station): I love the Gale site. It is exciting for science and for exploration. The rover will be able to explore sedimentary rock layers that have been altered by water. It will do this while moving through picturesque canyons and with a view of a 5-km tall mound. [Gale Crater FAQ: Mars Landing Spot for Next Rover Explained]
With such a singular mound of sedimentary rocks, the view will combine aspects of seeing Mt. Rainier and the Grand Canyon. Along the way, the rover will see clays from a wetter Mars and could drive to where those clays meet the sulfates deposited during the drying out of the area.
As an atmospheric scientist, I am also looking forward to watching the seasons at the site. It was the site best positioned for seeing water-ice clouds that form every northern summer, when Mars is farthest from the sun.
All of the finalist sites were good, but Gale seemed to be the one that had the biggest story about Mars' history to tell.
Peter Smith (planetary scientist at the University of Arizona in Tucson): Gale Crater is an excellent site that allows exploration in the truest sense.
The challenges and rewards of driving a nuclear-powered rover up a 5-km mountain over several years will test the abilities of both the science and engineering team. I am sure that they are up to the task and look forward to the results.
Chris Carr (engineer and research scientist at MIT in Cambridge, Mass.): Any of the final four options (Gale Crater, Eberswalde Crater, Holden Crater or Mawrth Vallis) originally considered by NASA would have been great (that is why those sites made it to the top four).
One challenge for Gale Crater is the need to traverse a significant distance to reach the central mound of the crater, where the rover could study the stratigraphic layers of (presumed) clays and sulfates.
These deposits are very interesting, because on Earth such deposits can preserve organic materials over geologic timescales. For example, some lipids can be preserved for up to billions of years.
Chris McKay (astrobiologist at NASA's Ames Research Center in Moffett Field, Calif.): I am happy with the decision to go with Gale Crater.
SPACE.com: What are the most exciting or interesting aspects of Gale?
McKay: The prospects of investigating clays and sedimentary layers that span most of, if not all of, Mars history in the central mount in Gale Crater.
Zuber: The center of Gale Crater features a 5-km-high mountain that contains layers that grade in composition from bottom to top. The rocks preserve the record of surface chemistry that appears to have been influenced greatly by water. [Video: Fly Over Gale Crater on Mars]
The evidence for water ranges from the deposition of the mountain itself to the chemistry of the rocks to channels that cut the terrain, and argues for an extended and changing aqueous history.
Smith: The wealth of water-related features and altered minerals opens a window onto the past history of Mars that has never before been explored. My hope is that there remains ample evidence showing that organic materials were common in ancient Mars.
Slowly working our way up through the layered deposits is sedimentary geology done in a classical fashion. Can we find the transition from an early wet Mars to the modern dry state that we see today? The question then is what happened to the water — Gale Crater may hold the answer.
Carr: The thick stratigraphic layers of the Gale Crater central mound. If Curiosity is able to traverse to and up through these layers, we will be taking a walk through time that covers a large swath of Martian history, a period when Mars may have been more habitable than it is today.
SPACE.com: Do you have high hopes for Curiosity's mission? What do you think it will find?
McKay: I do indeed have high hopes for Curiosity's mission. I think we will be able to detect organics on the surface of Mars.
My optimism on this is the result of the combined Phoenix and Viking results. Taken together, they imply that there are organics in the soils of Mars (at the few ppm [parts per million] level) but that the presence of perchlorate prevented their detection by the Viking instruments.
We believe that the instruments on Curiosity will be able to detect the few ppm organics even with the perchlorates present. So I expect that we'll have an exciting time trying to determine if there is any evidence for biological activity in the organics we find. The alternative is that the organics might be simply due to meteorite infall. [5 Bold Claims of Alien Life]
Zuber: Whenever we have looked in a new place at higher resolution or with new sensors, the discoveries have been remarkable, and I expect Curiosity to continue in the great tradition of Mars robotic explorers.
As far as what the rover will find, I have a wish rather than a prediction. I am hoping that as Curiosity moves up the stratigraphic section in the central mound and maps the evolving chemistry, that the measurements will inform our understanding of the role of the atmosphere in the evolving surface environment.
The question of how and over what period Mars lost much of its atmosphere, and how that relates to climate change, is one of the most compelling and puzzling questions in Mars science. [Photos: Curiosity Rover, NASA's Mars Science Laboratory]
Lemmon: If the rover lands safely, the investigation of the clays and sulfates at the base of the mound will put MSL onto the list of missions that revolutionize what we know about Mars.
Carr: I definitely have high hopes. This is an extremely capable rover with a tremendous set of instruments.
In particular, I am personally excited about the role the ChemCam instrument will play in providing rapid context at a distance, the in-depth sample analysis capability of the SAM instrument and the radiation data that will be collected by DAN, with its implications for modern habitability of Mars, including for future human visitors.
I make no predictions but hope we will find unambiguous evidence of organics among the layers in Gale Crater.
You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.
Wednesday, July 6, 2011
The Mars Science Laboratory rover, Curiosity, undergoes mobility testing inside the Spacecraft Assembly Facility to prepare it for its fall 2011 launch
Read more: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2011/07/05/MN3I1K5KK3.DTL#ixzz1RKTcGViC
Possibility for life on Mars found by scientists
David Perlman, Chronicle Science Editor
Wednesday, July 6, 2011
All it took was a hungry scientist to stop for lunch in the Mojave Desert, and suddenly there was a new prospect for seeking signs of life on Mars.
Space researcher Christopher P. McKay of NASA's Ames Research Center in the Santa Clara County city of Mountain View was hiking with friends a few years ago, when they stopped to picnic at a rocky desert spot called Little Red Hill near Barstow a few years ago.
McKay cracked open one of the rocks littering the ground all around him, and found clear white inside and a greenish tinge beneath.
At her lab in Mountain View, Janice L. Bishop, a geochemist at the SETI Institute, analyzed the rock to find that the white inside was basically a carbonate mineral called dolomite, with a mix of other carbonates. The carbonates had originally formed in water.
And the greenish tinge underneath the rock was a varied group of living microbe species called Chroococcidiopsis, known as cyanobacteria - blue-green algae.
Bishop analyzed more rocks from the Mojave and found they all held the same mix. The red coating was a form of iron oxide called hematite.
Bishop, McKay and their colleagues published a report in the July 1 issue of the International Journal of Astrobiology.
"We know that the red coating - like all the red rocks on Mars - is iron oxide that acts like a protective coat around the carbonates," McKay said in an interview Tuesday, describing the rock he found. "In the desert, the microbes underneath them need only a little sunlight coming in through cracks in the rocks to live by photosynthesis - it could have been the same on Mars."
Carbonates form in water, but carbonates on Mars have been detected only in several small areas. For example, instruments aboard the Mars rover Spirit, now stuck forever in the sand of Gusev crater, detected carbonates in a rock outcrop named "Pot of Gold" right after it first landed on the planet more than seven years ago. The Mars Reconnaissance Orbiter, aloft above the planet, has also detected carbonates in the rocks of a crater.
Knowing that, Bishop and McKay reason that, just as life lives beneath the red-tinged carbonate rocks in the Mojave, the red rocks on Mars' surface could well hide the evidence of fossil life underneath them.
"Iron oxides coating the rocks are everywhere on Mars," Bishop said. "We've found carbonates that formed in water inside the same desert varnish in the rocks from the Mojave. So they should be broadly distributed on Mars, too."
A spacecraft called the Mars Science Laboratory, a much larger and more powerful rover than either Spirit or its twin, Opportunity, is to be launched in the fall and will start exploring the planet next summer.
"That rover will be able to drill into the rocks when it starts exploring," McKay said.
The Mojave dessert was once a shallow sea some 250 million years ago, and the desert's carbonate rocks formed there. Today's living microbes sheltered beneath the rocks resulted from recent rains.
"We need to be looking for the same thing everywhere on Mars," McKay said. "Only landers - not orbiters - will be able to find them."
E-mail David Perlman at firstname.lastname@example.org.