NASA rover launched to seek out life clues on Mars

By Irene Klotz

CAPE CANAVERAL, Florida | Sun Nov 27, 2011 6:22am EST

CAPE CANAVERAL, Florida (Reuters) - An unmanned Atlas 5 rocket blasted off from Florida on Saturday, launching a $2.5 billion nuclear-powered NASA rover toward Mars to look for clues on what could sustain life on the Red Planet.

The 20-story-tall booster built by United Launch Alliance lifted off from its seaside launch pad at Cape Canaveral Air Force Station at 10:02 a.m. EST (3:02 p.m. GMT).

It soared through partly cloudy skies into space, carrying NASA's Mars Science Laboratory on a 354-million mile (556 million km), nearly nine-month journey to the planet.

"I think this mission is an important next step in NASA's overall goal to address the issue of life in the universe," lead scientist John Grotzinger, with the California Institute of Technology, told reporters shortly after the launch.

The car-sized rover, nicknamed Curiosity, is expected to touch down on August 6, 2012, to begin two years of detailed analysis of a 96-mile (154-km) wide impact basin near the Martian equator called Gale Crater.

The goal is to determine if Mars has or ever had environments to support life. It is the first astrobiology mission to Mars since the 1970s-era Viking probes.

Scientists chose the landing site because it has a three-mile-high (4.8-km high) mountain of what appears from orbital imagery and mineral analysis to be layers of rock piled up like the Grand Canyon, each layer testifying to a different period in Mars' history.

The rover has 17 cameras and 10 science instruments, including chemistry labs, to identify elements in soil and rock samples to be dug up by the probe's drill-tipped robotic arm.

'LONG SHOT'

The base of the crater's mountain has clays, evidence of a prolonged wet environment, and what appears to be minerals such as sulfates that likely were deposited as water evaporated.

Water is considered to be a key element for life, but not the only one.

Previous Mars probes, including the rovers Spirit and Opportunity, searched for signs of past surface water.

"We are not a life-detection mission," Grotzinger said. "We have no ability to detect life present on the surface of Mars. It's an intermediate mission between the search for water and future missions, which may undertake life detection."

With Curiosity, which is twice as long and three times heavier than its predecessors, NASA shifts its focus to look for other ingredients for life, including possibly organic carbon, the building block for life on Earth.

"It's a long shot, but we're going to try," Grotzinger said.

Launch is generally considered the riskiest part of a mission, but Curiosity's landing on Mars will not be without drama.

The 1,980-pound (898 kg) rover is too big for the airbag or thruster-rocket landings used on previous Mars probes, so engineers designed a rocket-powered "sky-crane" to gently lower Curiosity to the crater floor via a 43-foot (13-meter) cable.

"We call it the 'six-minutes of terror,'" said Doug McCuistion, director of NASA's Mars Exploration Program, referring to the landing. "It is pretty scary, but my confidence level is really high."

Curiosity is powered by heat from the radioactive decay of plutonium. It is designed to last one Martian year, or 687 Earth days.

Source: http://feeds.reuters.com/~r/reuters/scienceNews/~3/p_MPQrgqTjg/us-space-mars-idUSTRE7AN0AT20111127

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Small forest with big impact: Fragmented rainforests maintain their ecological functionality

ScienceDaily (Nov. 25, 2011) ? The value of a rainforest is not only measured by its biological diversity but also by its ecological functionality. Scientists have now presented the results of a comprehensive study in Kenya carried out over the course of nine years within the framework of the BIOTA East Africa project, which was supported by the German Federal Ministry of Education and Research. A team of authors lead by Dr. Matthias Schleuning (Biodiversity and Climate Research Centre, BiK-F) writes in the open-access journal PLoS One that rainforests that are subject to use by the human population and are divided into forest fragments can maintain their ecological functionality.

The results are surprising: "What we didn't expect was the fact that the intensity of ecosystem functions such as decomposition, pollination or seed dispersal remain stable or have in some cases even increased in fragmented forests, in which selective logging of trees occurs. This means that the overall functionality of these forests has been preserved, despite moderate human disturbance," says Dr. Matthias Schleuning (BiK-F), lead author of the study. The results might well stimulate a rethink in the area of tropical forest conservation. "The classical approach is to preserve large, intact forest areas, such as the Amazon or Congo basins. Our study shows that it can also make sense to protect the many isolated rainforests that have been influenced by humans." explains Schleuning. The location of the study was the Kakamega rainforest in Western Kenya. It contains a high biological diversity, including over 400 bird and more than 320 ant species. However, the forest is under threat, because its area has shrunk by more than half of its former size in the last century. The once enclosed forest area has now become a series of isolated forest fragments, surrounded by agricultural land on which primarily sugarcane and maize is grown. The remaining forest is nowadays still used by the human population and individual trees continue to be felled in spite of protective measures.

Is the Kenyan rainforest still able to function?

The consequences of these human interventions for the ecosystem functionality and biodiversity in the Kakamega rainforest was examined by Schleuning and his colleagues within the framework of the German-African research programme BIOTA. The scientists concentrated on six ecosystem functions. The forest's ecological functionality can be measured according to criteria such as decomposition, predation of seeds, pollination, seed dispersal and insect predation by army-ants and ant birds. In contrast to previous studies, which analysed primarily biodiversity changes in rainforests, the current study observed biodiversity and ecosystem functions together, and for the first time a number of functions were examined simultaneously. At eleven sample sites, the scientists recorded the diversity of different groups of animals and studied their ecosystem functions in experiments. For example, leaf samples were laid out and measurements were taken as to how quickly the material degraded. In order to measure the intensity of the raids of the army-ants, hundreds of traps were buried in the ground and evaluated.

Fragmentation and selective logging have different effects

It was shown that ecosystem functions -- though generally stable -- are influenced to different degrees by forest fragmentation and the selective logging of individual trees. When large forest areas develop into isolated forest fragments, the effects on the ecosystem functions are especially noticeable in instances where the composition of the animal communities changes substantially. Selective logging impacts primarily on ecosystem functions in which mobile animal species play a role. The scientists thus noticed positive effects on pollination by insects, seed dispersal by birds and also on the raids of the army-ants -- probably due to the altered movement patterns of these species. Schleuning says: "The mechanisms of the two types of human intervention are different. Fragmentation tends to have an indirect influence on ecosystem functions. The fragmentation of forests changes the biological diversity, which causes a threat to the preservation of their ecosystem functions. In contrast, selective logging impacts directly on ecosystem functions and has, at the moderate intensities in our study area, hardly any effect on the diversity of the animal species we examined. The next step would now involve projects that would examine the long-term functionality of the fragmented forests."

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Story Source:

The above story is reprinted from materials provided by Senckenberg Research Institute and Natural History Museum, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Matthias Schleuning, Nina Farwig, Marcell K. Peters, Thomas Bergsdorf, B?rbel Bleher, Roland Brandl, Helmut Dalitz, Georg Fischer, Wolfram Freund, Mary W. Gikungu, Melanie Hagen, Francisco Hita Garcia, Godfrey H. Kagezi, Manfred Kaib, Manfred Kraemer, Tobias Lung, Clas M. Naumann, Gertrud Schaab, Mathias Templin, Dana Uster, J. Wolfgang W?gele, Katrin B?hning-Gaese. Forest Fragmentation and Selective Logging Have Inconsistent Effects on Multiple Animal-Mediated Ecosystem Processes in a Tropical Forest. PLoS ONE, 2011; 6 (11): e27785 DOI: 10.1371/journal.pone.0027785

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Source: http://www.sciencedaily.com/releases/2011/11/111125160856.htm

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