Monday, May 24, 2010

Phoenix Mars Lander is Silent, New Image Shows Damage

Two images of the Phoenix Mars lander taken from Martian orbit in 2008 and 2010. The 2008 lander image shows two relatively blue spots on either side corresponding to the spacecraft's clean circular solar panels. In the 2010 image scientists see a dark shadow that could be the lander body and eastern solar panel, but no shadow from the western solar panel. Image credit: NASA/JPL-Caltech/University of Arizona
PASADENA, Calif. -- NASA's Phoenix Mars Lander has ended operations after repeated attempts to contact the spacecraft were unsuccessful. A new image transmitted by NASA's Mars Reconnaissance Orbiter shows signs of severe ice damage to the lander's solar panels.

"The Phoenix spacecraft succeeded in its investigations and exceeded its planned lifetime," said Fuk Li, manager of the Mars Exploration Program at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Although its work is finished, analysis of information from Phoenix's science activities will continue for some time to come."

Last week, NASA's Mars Odyssey orbiter flew over the Phoenix landing site 61 times during a final attempt to communicate with the lander. No transmission from the lander was detected. Phoenix also did not communicate during 150 flights in three earlier listening campaigns this year.

Earth-based research continues on discoveries Phoenix made during summer conditions at the far-northern site where it landed May 25, 2008. The solar-powered lander completed its three-month mission and kept working until sunlight waned two months later.

This view of one of the Mars Phoenix Lander's solar panels is a composite of multiple exposures taken by the spacecraft's Surface Stereo Imager camera. Image credit: NASA/JPL-Caltech/University Arizona/Texas A&M University
Phoenix was not designed to survive the dark, cold, icy winter. However, the slim possibility Phoenix survived could not be eliminated without listening for the lander after abundant sunshine returned.

An image of Phoenix taken this month by the High Resolution Imaging Science Experiment, or HiRISE, camera on board the Mars Reconnaissance Orbiter suggests the lander no longer casts shadows the way it did during its working lifetime.

"Before and after images are dramatically different," said Michael Mellon of the University of Colorado in Boulder, a science team member for both Phoenix and HiRISE. "The lander looks smaller, and only a portion of the difference can be explained by accumulation of dust on the lander, which makes its surfaces less distinguishable from surrounding ground."

Apparent changes in the shadows cast by the lander are consistent with predictions of how Phoenix could be damaged by harsh winter conditions. It was anticipated that the weight of a carbon-dioxide ice buildup could bend or break the lander's solar panels. Mellon calculated hundreds of pounds of ice probably coated the lander in mid-winter.

During its mission, Phoenix confirmed and examined patches of the widespread deposits of underground water ice detected by Odyssey and identified a mineral called calcium carbonate that suggested occasional presence of thawed water. The lander also found soil chemistry with significant implications for life and observed falling snow. The mission's biggest surprise was the discovery of perchlorate, an oxidizing chemical on Earth that is food for some microbes and potentially toxic for others.

"We found that the soil above the ice can act like a sponge, with perchlorate scavenging water from the atmosphere and holding on to it," said Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson. "You can have a thin film layer of water capable of being a habitable environment. A micro-world at the scale of grains of soil -- that's where the action is."

The perchlorate results are shaping subsequent astrobiology research, as scientists investigate the implications of its antifreeze properties and potential use as an energy source by microbes. Discovery of the ice in the uppermost soil by Odyssey pointed the way for Phoenix. More recently, the Mars Reconnaissance Orbiter detected numerous ice deposits in middle latitudes at greater depth using radar and exposed on the surface by fresh impact craters.

"Ice-rich environments are an even bigger part of the planet than we thought," Smith said. "Somewhere in that vast region there are going to be places that are more habitable than others."

The Mars Reconnaissance Orbiter reached the planet in 2006 to begin a two-year primary science mission. Its data show Mars had diverse wet environments at many locations for differing durations during the planet's history, and climate-change cycles persist into the present era. The mission has returned more planetary data than all other Mars missions combined.

Thursday, May 20, 2010

NASA Uses 'Polka Dots' For Precision Measurements

Rob Black, senior applications engineer with Shape Fidelity Inc., of Huntsville, Ala., a contractor with the Ares I Upper Stage team, sets up for photogrammetry process.What weighs 600 pounds, is shiny-silver with black and white polka dots and shaped like an upside-down saucer? If you guessed some sort of mod, fancy looking UFO, you are close. It's a fuel tank dome being developed for NASA's next-generation launch vehicles.

But why polka dots? They are part of an engineering tool called photogrammetry, the practice of determining the geometric properties of objects from photographic images. It is a process used by engineers at NASA's Marshall Space Flight Center in Huntsville, Ala., to accurately measure most everything from hardware to the tools used to make the hardware. Analytical photogrammetry is now routinely employed in tasks as diverse as machine tool inspection, fixture checking and structural deformation monitoring.

"This is a reasonably cheap process that provides engineers with a precise, three-dimensional measuring tool," said Sandeep Shah, upper stage manufacturing and assembly subsystem manager for Ares Projects at the Marshall Center. "It's a novel application of an existing technology that allows us to capture the true geometry of parts and components as they are produced, and provides immediate feedback to our team."

So How Does It Work?
The system typically requires only two engineers, a computer, a camera, targets or dots, two scale bars -- used as points of reference because of their exact length -- and a specially designed 3-D scanner.

"That’s what makes photogrammetry such a great tool," Shah said. "It's simple, mobile, fast, cheap and extremely accurate. Though we've only used photogrammetry for a couple of years, I can't imagine future development and production of flight hardware without it."

First, black and white target dots are irregularly placed several inches apart on the test object. The irregular spacing is designed to assist the computer software in identifying each individual target. Next, the engineer takes pictures of the test article from every angle, using a standard, 10-megapixel camera. The number of photographs needed varies depending on the size and shape of the test article. The photos then are transferred to a computer, where the software identifies the targets to produce a skeleton-like outline, referred to as an optical global framework.

Finally, a three-dimensional, white-light scanner is used to scan small sections of the test article -- producing accurate surface definitions and thus a near-perfect computer-aided design, or CAD, model.

Tuesday, May 18, 2010

NASA Invites Public to Take Virtual Walk on Moon

More than 37 years after humans last walked on the moon, planetary scientists are inviting members of the public to return to the lunar surface as “virtual astronauts” to help answer important scientific questions.

No spacesuit or rocket ship is required -- all visitors need to do is go to and be among the first to see the lunar surface in unprecedented detail. New high-resolution images, taken by NASA’s Lunar Reconnaissance Orbiter Camera (LROC), offer exciting clues to unveil or reveal the history of the moon and our solar system.

“We need Web users around the world to help us interpret these stunning new images of the lunar surface,” said Chris Lintott of Oxford University and chair of the Citizen Science Alliance. “If you only spend five minutes on the site counting craters you’ll be making a valuable contribution to science and, who knows, you might run across a Russian spacecraft.”

Scientists are particularly interested in knowing how many craters appear in a particular region of the moon in order to determine the age and depth of the lunar surface (regolith). Fresh craters left by recent impacts provide clues about the potential risks from meteor strikes on the moon and on Earth.

“We hope to address key questions about the impact bombardment history of the moon and discover sites of geological interest that have never been seen before,” said Katherine Joy of the Lunar and Planetary Institute and a Moon Zoo science team member.

NASA Lunar Science Institute (NLSI) scientists are contributing to the Moon Zoo efforts by providing science expertise. NLSI is also providing educational content and supporting outreach goals of the project.

“The NASA Lunar Science Institute is very excited to be involved with Moon Zoo and support lunar citizen science,” said David Morrison, NLSI director. “Science and public outreach are cornerstones of our Institute; Moon Zoo will contribute to the accomplishment of important science, while being a major step forward in participatory exploration.”

The Moon Zoo Web site is a citizen science project developed by the Citizen Science Alliance, a group of research organizations and museums, and builds on the team's success with Galaxy Zoo, which has involved more than 250,000 people in astronomical research.

“The Lunar Reconnaissance Orbiter Project Science Office is excited to see LRO data being used for citizen science projects,” said Rich Vondrak, LRO project scientist from NASA’s Goddard Space Flight Center, Greenbelt, Md. “The Moon Zoo project provides an opportunity for everyone to participate in analysis of images from the LRO Camera and to make a significant contribution to scientific knowledge about the moon.”

The Lunar Reconnaissance Orbiter mission is managed by NASA's Goddard Space Flight Center, Greenbelt, Md. and the LROC instruments are based out of Arizona State University in Tempe, Az. The NASA Lunar Science Institute is based out of NASA’s Ames Research Center, Moffett Field, Calif.

Thursday, May 06, 2010

HELP HELP NASA Keeping Eyes in the Sky on the Gulf Oil Spill

NASA's Terra satellite flew over the Deepwater Horizon rig's oil spill in the Gulf of Mexico on Saturday, May 1 and captured a natural-color image of the slick from space. The oil slick resulted from an accident at the Deepwater Horizon rig in the Gulf of Mexico.

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA’s Terra satellite captured a natural-color image. The oil slick appeared as a tangle of dull gray on the ocean surface, made visible to the satellite sensor by the sun’s reflection on the ocean surface. On May 1, most of the oil slick was southeast of the Mississippi Delta.

The National Oceanic and Atmospheric Administration (NOAA) is the lead agency on oil spills and uses airplane fly-over's to assess oil spill extent. NASA's Terra and Aqua satellites are also helping NOAA with satellite images of the area.

On Sunday, May 2, NOAA restricted fishing in federal waters of the Gulf of Mexico from the mouth of the Mississippi to Pensacola Bay for at least ten days. More details about the closure can be found at: In addition to the federal closure, Louisiana closed vulnerable fisheries in state waters -- within three miles of the coast. NOAA noted that anyone wanting to report oil on land, or for general Community and Volunteer Information, please call 1-866-448-5816. To report oiled or injured wildlife, please call 1-800-557-1401.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.