ASU News - Earth / Space

Research shows impacts from airborne nitrogen

mcoulomb — Thu, 05 Nov 2009 10:06:37 -0700

The impact of airborne nitrogen released from the burning of fossil fuels and widespread use of fertilizers in agriculture is much greater than previously recognized and even extends to remote alpine lakes, according to a study published Nov. 6 in the journal Science.

Examining nitrogen deposition in alpine and subalpine lakes in Colorado, Sweden and Norway, James Elser, a limnologist in the School of Life Sciences at Arizona State University, and his colleagues found that, on average, nitrogen levels in lakes were elevated, even those isolated from urban and agricultural centers.

The article “Shifts in lake N:P stoichiometry and nutrient limitation driven by atmospheric nitrogen deposition” presents experimental data from more than 90 lakes. The researchers’ collaboration also revealed that nitrogen-rich air pollution has already altered the lakes’ fundamental ecology.

“This is because plant plankton or phytoplankton, like all plants, need nitrogen and phosphorus for growth,” Elser says. “Inputs from pollution in the atmosphere appear to shift the supplies of nitrogen relative to other elements, like phosphorus.”

The increase in the availability of nitrogen means that growing phytoplankton in lakes receiving elevated nitrogen deposition are now limited by how much phosphorus they can acquire. Elser says that this is important because “we know that phosphorus-limited phytoplankton are poor food – basically ‘junk food’ for animal plankton, which in turn are food for fish.”

“Such a shift could potentially affect biodiversity,” he adds. “However, we don’t really know because unlike in terrestrial systems, the impacts of nitrogen deposition on aquatic systems have not been widely studied.”

Elser’s collaborators include researchers Tom Andersen and Dag Hessen from the University of Oslo; Jill Baron of the United States Geological Survey and Natural Resource Ecology Laboratory at Colorado State University; Ann-Kristin Bergström and Mats Jansson with Umeå University, Sweden; and Koren Nydick of the Mountain Studies Institute in Colorado, in addition to Marcia Kyle and Laura Steger, who are members of his own group in ASU’s College of Liberal Arts and Sciences.

Hessen, a well-known limnologist, and Elser have had a long-standing collaborative relationship, looking not only at nitrogen deposition but also zooplankton nutrition and a broad range of stoichiometric studies. Elser met Bergström at a conference at Umeå University and discovered that she had performed similar experiments in Sweden.

“By combining these studies we were able to achieve a more global picture of how nitrogen was impacting a broad range of lakes and come to firmer conclusions about effects of deposition,” Elser says.

Elser and Hessen hope to expand on these findings and have a pending grant proposal with the Norwegian government. In addition, Elser says he hopes to perform similar studies in China “where atmospheric nitrogen pollution is extremely high,” but, as yet, unstudied.

Elser has built a career around asking questions about energy and material flows in ecosystems, and traveling all over the world to find answers.Understanding the balance of phosphorus, carbon and nitrogen in systems forms the backbone of Elser’s worldview, known as “stoichiometric theory.” His pioneering studies have jumpstarted new research approaches, insights into nutrient limitation, trophic dynamics, biogeochemical cycling, and linkages between evolutionary and ecosystem processes. This study was supported by the National Science Foundation.

Researchers discover new wrinkle in ancient ocean chemistry

jgreen1 — Thu, 29 Oct 2009 23:12:44 -0600

Scientists widely accept that around 2.4 billion years ago, the Earth's atmosphere underwent a dramatic change when oxygen levels rose sharply. Called the "Great Oxidation Event" (GOE), the oxygen spike marks an important milestone in Earth's history, the transformation from an oxygen-poor atmosphere to an oxygen-rich one, paving the way for complex life to develop on the planet.

Two questions that remain unresolved in studies of the early Earth are when oxygen production via photosynthesis got started and when it began to alter the chemistry of Earth's ocean and atmosphere.

ASU scientists, working with collaborators at other institutions, have been pursuing these questions in a series of studies of ancient rocks from Western Australia. The latest of these studies appears in the Oct. 30 issue of the journal Science.

The new findings corroborate previous results that oxygen production began in Earth's oceans at least 100 million years before the GOE, but also go a step further in demonstrating that even very low concentrations of oxygen can have profound effects on ocean chemistry. This research was led by geoscientists at the University of California, Riverside, working with Ariel Anbar, an astrobiologist and biogeochemist. Anbar, a co-author on the research, is a professor in the department of chemistry and biochemistry and the School of Earth and Space Exploration in ASU's College of Liberal Arts and Sciences.

To arrive at their results, the researchers analyzed 2.5 billion-year-old black shales from Western Australia. Essentially representing fossilized pieces of the ancient seafloor, the fine layers within the rocks allowed the researchers to page through ocean chemistry's evolving history. These rocks were obtained under the leadership of Anbar, with support from the NASA Astrobiology Institute of which ASU is a member.

Specifically, the shales revealed that episodes of hydrogen sulfide accumulation in the oxygen-free deep ocean occurred nearly 100 million years before the GOE and up to 700 million years earlier than such conditions were predicted by past models for the early ocean. Scientists have long believed that the early ocean, for more than half of Earth's 4.6 billion-year history, was characterized instead by high amounts of dissolved iron under conditions of essentially no oxygen.

"The conventional wisdom has been that appreciable atmospheric oxygen is needed for sulfidic conditions to develop in the ocean," said Chris Reinhard, a doctoral student at UCR and lead author of the research paper. "We found, however, that sulfidic conditions in the ocean are possible even when there is very little oxygen around, below about 1/100,000th of the oxygen in the modern atmosphere."

Reinhard explained that at even very low oxygen levels in the atmosphere, the mineral pyrite can weather on the continents, resulting in the delivery of sulfate to the ocean by rivers. Sulfate is the key ingredient in hydrogen sulfide formation in the ocean.

Timothy Lyons, a professor of biogeochemistry at UCR, whose laboratory led the research, explained that the hydrogen sulfide in the ocean is a fingerprint of photosynthetic production of oxygen 2.5 billion years ago.

"A pre-GOE emergence for oxygenic photosynthesis is a matter of intense debate, and its resolution lies at the heart of understanding the evolution of diverse forms of life," he said. "We have found an important piece of that puzzle."

"These data don't make much sense unless there were at least small amounts of oxygen in the environment. The simplest explanation is oxygen-producing photosynthesis long before concentrations of oxygen in the atmosphere were even a tiny fraction of what they are today," said Anbar. "The results are beautifully consistent with our previous results. The story just gets stronger and stronger the more we look at these ancient sediments."

The researchers argue that the presence of small amounts of oxygen may have stimulated the early evolution of eukaryotes - organisms whose cells bear nuclei - millions of years prior to the GOE.

"This initial oxygen production set the stage for the development of animals almost two billion years later," Lyons said. "The evolution of eukaryotes had to take place first."

The findings also have implications for the search for life on extrasolar planets.

"Our findings add to growing evidence suggesting that biological production of oxygen is a necessary but not sufficient condition for the evolution of complex life," Reinhard said. "A planetary atmosphere with abundant oxygen would provide a very promising biosignature. But one of the lessons here is that just because spectroscopic measurements don't detect oxygen in the atmosphere of another planet doesn't necessarily mean that no biological oxygen production is taking place."

Anbar, Reinhard and Lyons were joined in the research by Clint Scott of UCR and Rob Raiswell of the University of Leeds, United Kingdom.

The two-year study was supported by the National Science Foundation and NASA.

Nobel laureate Giacconi: Astronomical discoveries require new physics

chughes3 — Thu, 15 Oct 2009 18:00:19 -0600

In 1609 Galileo turned the eyes of science to the frontier of space. Now, 400 years after the discovery of the telescope, Nobel laureate Riccardo Giacconi of Johns Hopkins University looks to detail a new period of heroic astronomical discoveries, comparable in impact on human understanding of the universe to those made by the "father of modern science" himself.

Giacconi shared the Nobel Prize in Physics in 2002 for his pioneering contributions to astrophysics, which led to the discovery of cosmic X-ray sources. He will deliver a public lecture titled "A New Revolution in Astronomy 400 years after Galileo" at 7:30 p.m. Oct. 28 at Arizona State University. The lecture is a part of the Distinguished Lecturer Series presented by ASU's Physics Department in the College of Liberal Arts and Sciences. It will be held in the Bateman Physical Sciences F Wing, Room 173, on ASU's Tempe campus. A reception precedes the lecture at 7 p.m.

"We live in a new heroic period of astronomical discoveries comparable for its impact on human understanding of the universe to that which occurred from Copernicus to Newton," said Giacconi. "New observatories in space and on the ground have opened up the study of the entire range of wavelengths emitted by celestial bodies reaching Earth from the farthest reaches of the cosmos.

"These studies have revealed the crucial role played by explosive events in the formation and development of the structures we now see. They also reveal the prevalence of unknown forms of matter and energy in our universe, where normal matter made of nucleons provides only 3 percent of the total," he said.

"These discoveries require new physics, just as it happened 400 years ago."

This Distinguished Lecture Series has brought internationally recognized scientists to the university campus to engage with students, faculty and community in many of the most exciting advances in science, according to Professor Robert Nemanich, chair of the ASU Physics Department.

"In the last few years, our perspective on the nature of the universe has been turned upside down as observations from new telescopes have forced a complete rethinking of the form of matter and energy in the universe. Professor and Nobel laureate Riccardo Giacconi has led many of the most significant observational research programs that have challenged and ultimately drastically changed our understanding," Nemanich said.

Giacconi is a fellow in the American Academy of Arts and Sciences, the American Astronomical Society and the American Association for the Advancement of Science. He started a group to do space science, proposed the first X-ray telescopes, and designed and built X-ray instruments for rocket flights to search for X-ray stars. In 1962, his group flew a rocket that discovered the first X-ray emitting star (Sco X-1). This discovery dawned a new age in X-ray astronomy, and led to the X-ray satellites UHURU, "Einstein" and Chandra.

Giacconi received a doctorate in physics from the University of Milan, Italy. In 1982 he became the founding director of the Space Telescope Science Institute in Baltimore. There he applied the techniques developed for the Einstein satellite to create the data reduction and archiving systems for the Hubble Telescope.

In 2008 Giacconi received the Lifetime Achievement Award from the National Inventors Hall of Fame in recognition for half a century's worth of unmatched contributions to observational capabilities in the modern world.

In addition to the public lecture, Giacconi will deliver a colloquium at 3:15 p.m. Oct. 29 in the Bateman Physical Sciences F Wing, Room 101. The title of his talk is "X-Ray Astronomy 2009."

The lecture and the colloquium are free and open to the public; seating is on a first-come, first-served basis. For more information call 480-965-3561 or visit the department's Web site, http://physics.asu.edu. For online maps of the Tempe campus and parking facilities visit www.asu.edu/map.

Written by Dan Moore (dhmoore@asu.edu) for the College of Liberal Arts and Sciences

MEDIA CONTACT
Carol Hughes, carol.hughes@asu.edu
480-965-6375

Europa or Mars: Where Could Extraterrestrial Life Be Found First?

nstaab — Thu, 15 Oct 2009 09:32:37 -0600

Future space missions have targeted Mars and Europa, an icy moon of Jupiter, as destinations to send new robotic explorers. According to an article published on SPACE.com on Oct. 12, these two may hold the best hopes for scientists trying to track down extraterrestrial life, at least in this solar system.

Writer Jeremy Hsu interviewed Professor Jack Farmer, an astrobiologist, for his opinions on where extraterrestrial life could be found first.

"We're much farther down the road with Mars than Europa," said Farmer. "My view is that habitable environments on Mars are likely to only be found in the deeper subsurface where we might have a hydrosphere."

"Europa's a very appealing target for astrobiology, and particularly from the standpoint of what life forms might be working in a sub-surface ocean," Farmer noted. "The challenge with Europa is that we don't know for sure if there's a sub-surface ocean."

ASU-generated research highlighted in 'Science'

nstaab — Fri, 25 Sep 2009 10:24:17 -0600

"How do you peer into the heart of a continent to see what makes it tick?" That's the question that Richard Kerr asks in the 25 Sept. issue of Science. The answer is the National Science Foundation's EarthScope project, a project that is revolutionizing how scientists see earth's interior.

One component of the EarthScope Project is USArray, a continental-scale seismic observatory which comprises a dense network of permanent and portable seismometers designed to record seismic waves from earthquakes all over the world to help image the deep earth. The seismic stations of the USArray Transportable Array, one of the four major components of the USArray facility, record earthquakes from around the globe. As the seismic waves propagate through the earth, they are affected by the structure and composition along their travel paths, which allow scientists to deduce details of the structure between source and station.

Imaging of crustal and upper mantle structure is an important starting point for understanding the dynamic processes and history of our planet. Many of the images of earth's interior that geophysicists have constructed up to this point have been quite blurry, but as the transportable array slowly marches across the lower 48 states, features of the earth's interior are being revealed in unprecedented resolution.

The array consists of an 800-kilometer wide (497-mile wide) grid of 400 highly capable seismometers 70 kilometers (44 miles) apart. Over the course of 12 years, the seismic stations are moved in a leapfrog fashion to cover the whole United States. The first group of 400 seismometers was deployed in the Western part of the United States. Today, it stretches 2,000 kilometers (1,243 miles) along the Rocky Mountains from the Canadian border to the Mexican border and into the Midwestern U.S. The stations continuously roll across the U.S. at a rate of just over one station per day, every day of the year.

Kerr quotes Edward Garnero, a seismologist and professor in the School of Earth and Space Exploration in the College of Liberal Arts and Sciences, as saying that researchers "are jumping up and down" with all the new data USArray is providing. Since USArray's inception, Garnero has been using the data for many projects; he is one of the many researchers in the school involved with and reliant upon the data from the transportable array.

"Once you use the data for a project, it is really hard to go back to other networks of seismic data," Garnero explains. "USArray ‘listens' to the earth with such incredible fidelity, owing to the really dense station coverage over such a large area, with state of the art equipment."

Many research projects have enabled substantially more detailed images thanks to the USArray, many of which have been ASU-generated results. In the 24 May issue of Nature Geoscience, seismologist John West, a graduate student in the School of Earth and Space Exploration, in collaboration with ASU geophysics professor Matthew Fouch and colleagues, reported the discovery of a 500-kilometer tall (311-mile-tall) drip beneath South-Central Nevada.

In the article, Kerr highlights ASU seismic models. Last year, ASU graduate student Jeff Roth published a paper showing some of the first tomographic images. Kerr also brings ASU into the discussion pertaining to the analysis of the images of the region beneath Yellowstone. Rather than a contorted columnar plume, Kerr says that "Fouch and his colleagues see a bent, thin ‘hot sheet' extending between shallow and deep blobs of hot rock in their processed seismic data."

Kerr notes that although the images generated through USArray data are now sharper, it doesn't mean that all the scientists are coming to the same conclusion about the interpretation of the images. He points out that much more work is left to be done to understand the details of the images, and quotes Fouch as saying that with each group's different processing of the same data, "you can let tomography become a Rorschach test."

The hunt for extraterrestrial life gets weird

nstaab — Wed, 23 Sep 2009 10:02:57 -0600

Humans have long pondered the possibility that life exists beyond Earth, but so far the quest for habitable worlds has focused on searching for water since life here requires it. In Wired Science's Sept. 22 article "The Hunt For Extraterrestrial Life Gets Weird", writer Hadley Leggett examines the efforts of researchers from Austria who have started a systematic study of solvents other than water that might be able to support life outside our planet. Leggett includes in the article Ariel Anbar, a professor in the School of Earth and Space Exploration and the department of chemistry and biochemistry and head of ASU's Astrobiology team. As one of the new NASA Astrobiology Institute teams, ASU researchers intend to boost extraterrestrial exploration to the next stage by refining the criteria that guide the search for life.

According to Anbar, the Austrian researchers are not the first to consider the possibility of exotic life supported by a solvent other than water. The idea dates back to at least 1954, when J.B.S. Haldane speculated that ammonia might be able to sustain life. He says that "the notion of alternative solvents is certainly plausible, though entirely unproven." Anbar goes on to say that the topic has received less attention than it deserves because life as we don't know it is so hard to study.

Anbar claims that the search for extraterrestrial life is limited more by our access to extraterrestrial environments than by our conception of what life might look like.

"However, as we plan future missions to Mars and elsewhere, especially Titan," he said, "and as we begin to consider the prospects for life in the solar systems other than our own that are being discovered at a rapid pace, it's important to begin thinking about ‘weird life' so that we don't miss something under our noses."

Learn more about the Astrobiology team at ASU: http://astrobiology.asu.edu/Astrobiology/Home/Home.html

ASU seismologists’ research featured in EarthScope newsletter

nstaab — Tue, 22 Sep 2009 15:52:31 -0600

Determining what lies beneath Earth's surface requires sophisticated technology. Ed Garnero, a professor in the School of Earth and Space Exploration in the College of Liberal Arts and Sciences, and seismology graduate student Chunpeng Zhao use seismic wave data from the USArray Transportable Array to construct a picture of the deep earth. The fall 2009 issue of onSite, the newsletter of the earth science program EarthScope, featured the research of Garnero and Zhao on the front page in the article, "Heterogeneous Lowermost Mantle Beneath the Pacific Ocean."

The seismic stations of the Transportable Array (TA) record earthquakes from around the globe. As seismic waves travel through the Earth, they are affected by the structure and composition they pass through. Scientists are then able to deduce Earth's structure between source and station. The dynamics and evolution of the deep interior are likely closely linked to Earth's outermost shell(s), including tectonic plates, their motions and evolution, making seismic imaging of deep Earth structure very important.

"To understand processes associated with low velocity provinces, it is important to constrain elastic property contrast across edges because strong lower mantle activities, e.g. partial melting, mineral phase transition or mantle flow, are usually associated with edges of these low velocity provinces," explains Chunpeng.

A more complete and better understanding of the area beneath the Pacific Ocean has long been a priority for seismologists since it is such a hotbed of activity. The TA is situated to record waves that originate from Fiji-Tonga, the spot from which the largest number of deep-focus earthquakes originates. Earlier studies had established the presence of a large low shear velocity province in the region below the Central Pacific. Garnero and Zhao have been able to add to this image, most notably by suggesting that the area is of a chemically distinct origin and mapping the northern edge of the low-velocity material.

According to Garnero, "Mapping out the details of these low velocities provinces, especially their edges, is a prerequisite for inferring deep mantle flow patterns responsible for sweeping the material into a pile in the first place. If we can learn more about deep mantle flow (and hence mantle convection in general), then there is hope that we might be able to better unravel the evolution of the interior, and hence planet as a whole."

For more information on EarthScope, or to read the fall 2009 newsletter, please visit: http://www.earthscope.org/

Robotics desert test provides NASA with new set of wheels for moon

nstaab — Wed, 16 Sep 2009 12:51:45 -0600

Every year, for two weeks in the Arizona desert at Black Point Lava Flow, NASA's Desert Research and Technology Studies group (Desert RATS) conducts technology development tests in anticipation of lunar exploration. Teams of engineers and geologists from several NASA laboratories as well as a variety of private and academic partners participated in this year's test, including two key members from ASU's School of Earth and Space Exploration.

New for this year was an intensive simulated mission during which two crew members, an astronaut and a geologist, lived for more than 300 hours inside NASA's new lunar wheels, the Lunar Electric Rover (LER). The explorers scouted the area for features of geological interest then donned spacesuits and conducted simulated moonwalks to collect samples. The crew also docked to a simulated habitat, drove the rover across difficult terrain, performed a rescue mission and made a four-day traverse across the rough landscape.

"We are continuously working to meet the challenges of a human outpost on the moon," says James Rice, faculty research associate in the school and principal investigator of one of the study's geology traverses. "To meet these challenges, scientists and engineers must conduct hands-on field tests and research here on earth to better prepare and understand the complex challenges that will be encountered on the moon."

Analogs are conducted to test robotics, vehicles, habitats and in-situ resource utilization in realistic environments that will aid astronauts, engineers and scientists as they define ways to combine human and robotic efforts to enhance scientific exploration. The Arizona desert is well suited for testing technologies and procedures for future human-robotic exploration in extreme environments.

"You have to test hardware and concepts in a real-world environment with real geology, slopes, rocks, dust ... and the unexpected," Rice says. "It can't be done in a controlled laboratory. The terrain of Black Point Lava Flow contains challenging topography for LER operations and also contains lunar and Mars analog geomorphology and geology."

Rice was in charge of making traverse routes or paths that the rover and crew followed during the simulation. He had to factor in science objectives, rover driving speed, time for the crew to put on and take off spacesuits before and after geology investigations, and the time required to drive to the next station.

"We had a very detailed timeline from Mission Control that we had to work with to make sure we achieved our science goals," says Rice, who has been involved with the field tests for about six years. "Sometimes we had issues with loss of communications, equipment or the rover and this caused the whole operation to get behind on the timeline. It was very realistic."

Kip Hodges, founding director of the school in ASU's College of Liberal Arts and Sciences, and science team member of Desert RATS, has been involved with this year's tests on a number of levels. He was the principal scientist of the K10 robot, which was developed at NASA's Ames Research Center and deployed prior to the simulated mission to identify areas of interest for the crew, and he served in the science "backroom" for the LER human tests.

"The K10 robot was employed in these tests in order to evaluate the added value of robotic reconnaissance of a planetary landscape prior to sending humans into the field for scientific research," says Hodges. "While the final field test results are not yet in, I think that my collaborators and I are extremely pleased with the exercise and looking forward to further tests. For example, we are also using K10 for follow-up work after human exploration. In that case, our analogue study site is in a bit farther afield: the high Arctic of Canada. Perhaps we'll also deploy K10 for this purpose next year at the Desert RATS tests."

New wheels for a new generation of exploration

LER, the next-generation rover, is an all-electric vehicle with 12 wheels. A little bigger than a Humvee, the LER was built for extreme exploration. The frame of this mobile base camp was developed in conjunction with an off-road race truck team, making it able to travel hundreds of kilometers over rugged terrain. Its wheels can move sideways in a "crabbing" motion, one of many features that make it skilled at scrambling over rocks. During the mission, LER was able to climb slopes on the lava flow that the team's SUV chase vehicles couldn't handle. Remarkably, the advanced suspension and drivetrain of the LER allows it to perform such feats using only 20 horsepower, an order of magnitude less than the standard off-road vehicles it left in the dust.

If that isn't enough to make the Apollo-era astronauts envious, LER is also capable of housing two astronauts for up to two weeks with sleeping and sanitary facilities. It is equipped with a time- and space-saving concept called suit ports, designed to allow astronauts to quickly enter and exit their EVA suits via a rear-entry hatch.

"Unlike during the Apollo Program where the astronauts had to drive their lunar rover wearing space suits," says Rice, "this new manned lunar rover concept with its pressurized environment will allow the crew to drive wearing more comfortable clothing and not be stuck in a space suit."

NASA has not yet confirmed the technologies that will be used in future lunar missions, but with the successful testing of analogue systems and procedures in simulated environments here on earth, we move one step closer to a sustainable human presence on the moon.

The Desert RATS tests have been held for more than a decade, as engineers from NASA centers work with representatives from industry and academia to determine what will be needed for human exploration of the moon and other destinations in the solar system. It is the culmination of the various individual science and advanced engineering discipline areas' year-long efforts. This year's work built on the investigations of previous years and increased the scope and length of the tests.

On Sept. 16, Kip Hodges appeared on Eight, Arizona PBS Horizon to discuss Desert RATS and the future of human space flight. Watch the interview here.

Space scientists meet at ASU to plan Mars exploration

rburnha2 — Fri, 04 Sep 2009 13:08:09 -0600

What should be the nation's goals and priorities for exploring Mars in the 2013-2022 timeframe?

To help answer this question, space scientists from the U.S. and around the world will gather Sept. 9-11 at the University Club on ASU's Tempe campus. Most of the discussions will be open to the public, in person and by Web cast at http://nasa-nai.acrobat.com/psdecadal/. Audio is at (866) 606-4717; use access code 7078222.

The meeting is sponsored by the National Academy of Sciences as part of its efforts to prepare a "Planetary Decadal Survey." The survey is not limited to just Mars but will cover all aspects of solar system exploration. It will broadly canvas planetary scientists to determine current knowledge and then identify the most important scientific questions they will face in the years 2013-2022.

The Mars Panel for the Decadal Survey is chaired by ASU's Philip Christensen, Regents' Professor of geological sciences in the School of Earth and Space Exploration. He is director of the Mars Space Flight Facility and also the principal investigator for several scientific instruments currently operating on NASA spacecraft at Mars.

ASU presenters at the meeting will include Meenakshi Wadhwa, director of the Center for Meteorite Studies, who will speak on the importance of acquiring Martian rock samples; and astrobiology researcher Jack Farmer, who has prepared a white paper on the astrobiological aspects of Mars exploration.

The Decadal Survey's final report, due March 2011, will be used by Congress and the Obama administration to determine which solar system exploration projects and missions should get highest priority in the 2010s.

For the meeting agenda and background white papers, see: http://mepag.jpl.nasa.gov/decadal/index.html

LRO camera takes first look at Apollo 12 landing site

nstaab — Thu, 03 Sep 2009 11:24:51 -0600

Just over a month ago, the imaging system on board NASA's Lunar Reconnaissance Orbiter (LRO) had its first of many opportunities to photograph five of the six Apollo landing sites. The LROC (short for Lunar Reconnaissance Orbiter Camera) team recently had the chance to target the remaining landing site.

The Apollo 12 landing site was well worth the wait. The Surveyor 3 spacecraft, Lunar Module descent stage and Apollo Lunar Surface Experiment Package (ALSEP), along with astronaut tracks, are all visible.

Mark Robinson, principal investigator of LROC and professor in the School of Earth and Space Exploration in the College of Liberal Arts and Sciences, provides a historical backdrop to the recently returned image:

After the great success of Apollo 11, NASA's next step was honing the Lunar Module's (LM) ability to make a pinpoint landing. Many of the future landing sites corresponded to areas with rough topography; the LM would have to come in steeply and set down within a few hundred meters of a designated point.
Pete Conrad (Commander) and Alan Bean (LM Pilot) piloted the Apollo 12 lunar module Intrepid to a landing within 200 meters (650 feet) of Surveyor 3 on November 14, 1969. This proved the pinpoint landing capability. It also allowed the astronauts to collect parts from the Surveyor for engineering assessment and provided the opportunity to sample ejecta from the Copernicus crater impact and what appeared from crater counts to be relatively young mare basalt.
During their brief stay of 31-and-a-half hours, the two astronauts performed two extra-vehicular activities (EVA), each a little under four hours in length.
On the first EVA, they deployed an Apollo Lunar Surface Experiment Package (ALSEP), which returned scientific data directly to the Earth for over seven years. Next the explorers headed to the northwest to collect soil and rock samples. In all they collected about 15 kilograms (33 pounds) of lunar samples on this first EVA.
The next day, Conrad and Bean headed out on the first lunar geologic traverse. They traveled west, skirting around Head crater, then south to Bench crater. At both locations the astronauts collected rock and soil samples and photographed the interiors of the two craters. After Bench, their furthest point from the LM was Sharp crater. Their next goal was a rendezvous with the Surveyor 3 spacecraft, some 450 meters (less than half a mile) to the east.
The Surveyor landed on the interior slope of what was later called Surveyor crater. There was some worry that as the astronauts removed parts from it, the spacecraft might slide downhill so they always stayed upslope.
In all, the Apollo 12 crew returned over 32 kilograms (70.5 pounds) of lunar samples. From these precious samples scientists learned that the Copernicus crater impact occurred some 810 million years ago; four different types of local basalts were sampled with ages much younger than those from Apollo 11, and a small sample of highlands rock previewed the complexity of the lunar highlands to be sampled on later Apollo missions. All in all, Apollo 12 was an incredible success and it paved the way for science missions to come.

In July, LRO was — and still is — in the commissioning phase. The highest priority of the LROC team at that point and the present time was testing and calibrating all the instruments to ensure that LROC could meet its mission requirements during the coming nominal mapping mission. Due to operational constraints, it was not possible to collect the Apollo 12 site, the westernmost landing site, at that time.

"There are only so many locations that can be imaged at one time," Robinson says. "Not every target can be imaged every time around. I'm glad we had to wait another month, it was very exciting to see this image a month after the excitement of the first round of Apollo landing sites."

LRO is slated to orbit the moon for at least another 12 months, which means Robinson and his team have many more imaging opportunities ahead of them. In mid-September the spacecraft's orbit will be lowered, allowing LROC to acquire even higher resolution images of the Apollo and Surveyor landing sites.

For additional information about the LROC instrument and to view more lunar images from LROC, visit: http://lroc.sese.asu.edu.