time travel

NASA-funded researchers are refining a tool that could not only check for the faintest traces of life’s molecular building blocks on Mars, but could also determine whether they have been produced by anything alive.The instrument, called Urey: Mars Organic and Oxidant Detector, has already shown its capabilities in one of the most barren climes on Earth, the Atacama Desert in Chile. The European Space Agency has chosen this tool from the United States as part of the science payload for the ExoMars rover planned for launch in 2013. Last month, NASA selected Urey for an instrument-development investment of $750,000.

The European Space Agency plans for the ExoMars rover to grind samples of Martian soil to fine powder and deliver them to a suite of analytical instruments, including Urey, that will search for signs of life. Each sample will be a spoonful of material dug from underground by a robotic drill.

“Urey will be able to detect key molecules associated with life at a sensitivity roughly a million times greater than previous instrumentation,” said Dr. Jeffrey Bada of Scripps Institution of Oceanography at the University of California, San Diego. Bada is the principal investigator for an international team of scientists and engineers working on various components of the device.

To aid in interpreting that information, part of the tool would assess how rapidly the environmental conditions on Mars erase those molecular clues.

Dr. Pascale Ehrenfreund of the University of Leiden in the Netherlands, said, “The main objective of ExoMars is to search for life. Urey will be a key instrument for that because it is the one with the highest sensitivity for organic chemicals.” Ehrenfreund, one of two deputy principal investigators for Urey, coordinates efforts of team members from five other European countries.

Urey can detect several types of organic molecules, such as amino acids, at concentrations as low as a few parts per trillion.

All life on Earth assembles chains of amino acids to make proteins. However, amino acids can be made either by a living organism or by non-biological means. This means it is possible that Mars has amino acids and other chemical precursors of life but has never had life. To distinguish between that situation and evidence for past or present life on Mars, the Urey instrument team will make use of the knowledge that most types of amino acids can exist in two different forms. One form is referred to as “left-handed” and the other as “right-handed.” Just as the right hand on a human mirrors the left, these two forms of an amino acid mirror each other.

Amino acids from a non-biological source come in a roughly 50-50 mix of right-handed and left-handed forms. Life on Earth, from the simplest microbes to the largest plants and animals, makes and uses only left-handed amino acids, with rare exceptions. Comparable uniformity — either all left or all right — is expected in any extraterrestrial life using building blocks that have mirror-image versions because a mixture would complicate biochemistry.

“The Urey instrument will be able to distinguish between left-handed amino acids and right-handed ones,” said Allen Farrington, Urey project manager at NASA’s Jet Propulsion Laboratory, which will build the instrument to be sent to Mars.

If Urey were to find an even mix of the mirror-image molecules on Mars, that would suggest life as we know it never began there. All-left or all-right would be strong evidence that life now exists on Mars, with all-right dramatically implying an origin separate from Earth life. Something between 50-50 and uniformity could result if Martian life once existed, because amino acids created biologically gradually change toward an even mixture in the absence of life.

The 1976 NASA Viking mission discovered that strongly oxidizing conditions at the Martian surface complicate experiments to search for life. The Urey instrument has a component, called the Mars oxidant instrument, for examining those conditions.

The oxidant instrument has microsensors coated with various chemical films. “By measuring the reaction of the sensor films with chemicals present in the Martian soil and atmosphere, we can establish if organisms could survive and if evidence of past life would be preserved,” said Dr. Richard Quinn, a co-investigator on Urey from the SETI Institute, Mountain View, Calif., who also works at NASA Ames Research Center, Moffett Field, Calif.

“In order to improve our chances of finding chemical evidence of life on Mars, and designing human habitats and other equipment that will function well on Mars’ surface, we need to improve our understanding of oxidants in the planet’s surface environment,” said Dr. Aaron Zent, a Urey co-investigator at NASA Ames.

A Urey component called the sub-critical water extractor handles the task of getting any organic compounds out of each powdered sample the ExoMars rover delivers to the instrument. “It’s like an espresso maker,” explained JPL’s Dr. Frank Grunthaner, a deputy principal investigator for Urey. “We bring the water with us. It is added to the sample, and different types of organic compounds dissolve into the liquid as the temperature increases. We keep it under pressure the whole time.”

The dissolved compounds are highly concentrated by stripping away water in a tiny oven.

Then a detector checks for fluorescent glowing, which would indicate the presence of amino acids, some components of DNA and RNA, or other organic compounds that bind to a fluorescing chemical added by the instrument.

A Urey component called the micro-capillary electrophoresis unit has the critical job of separating different types of organic compounds from one another for identification, including separation of mirror-image amino acids from each other. “We have essentially put a laboratory onto a single wafer,” said Dr. Richard Mathies of the University of California, Berkeley, a Urey co-investigator. The device for sending to Mars will be a small version incorporating this detection technology, which is already in use for biomedical procedures such as law-enforcement DNA tests and checking for hazardous microbes.

Switzerland will provide electronics design and packaging expertise for Urey. Micro-Cameras and Space Exploration S.A., Neuchatel, will collaborate with JPL and the European Space Agency to accomplish this significant contribution to the heart of the instrument. Dr. Jean-Luc Josset, Urey co-investigator at the University of Neuchatel will coordinate this effort and help provide detector selection and support. JPL is a division of the California Institute of Technology in Pasadena.

From NASA

Solar energy has the power to reduce greenhouse gases and provide increased energy efficiency, says a scientist at the U.S. Department of Energy’s Argonne National Laboratory, in a report (view it online) published in the March issue of Physics Today.

Last month, the Intergovernmental Panel on Climate Change (IPCC) of the United Nations released a report confirming global warming is upon us and attributing the growing threat to the man-made burning of fossil fuels.

Opportunities to increase solar energy conversion as an alternative to fossil fuels are addressed in the Physics Today article, co-authored by George Crabtree, senior scientist and director of Argonne’s Materials Science Division, and Nathan Lewis, professor of Chemistry at Caltech and director of its Molecular Materials Research Center.

Currently, between 80 percent and 85 percent of our energy comes from fossil fuels. However, fossil fuel resources are of finite extent and are distributed unevenly beneath Earth’s surface. When fossil fuel is turned into useful energy through combustion, it often produces environmental pollutants that are harmful to human health and greenhouse gases that threaten the global climate. In contrast, solar resources are widely available and have a benign effect on the environment and climate, making it an appealing alternative energy source.

“Sunlight is not only the most plentiful energy resource on earth, it is also one of the most versatile, converting readily to electricity, fuel and heat,” said Crabtree. “The challenge is to raise its conversion efficiency by factors of five or ten. That requires understanding the fundamental conversion phenomena at the nanoscale. We are just scratching the surface of this rich research field.”

Argonne carries out forefront basic research on all three solar conversion routes. The laboratory is creating next-generation nanostructured solar cells using sophisticated atomic layer deposition techniques that replace expensive silicon with inexpensive titanium dioxide and chemical dyes. Its artificial photosynthesis program imitates nature using simple chemical components to convert sunlight, water and carbon dioxide directly into fuels like hydrogen, methane and ethanol. Its program on thermoelectric materials takes heat from the sun and converts it directly to electricity.

The Physics Today article is based on the conclusions contained in the report of the Basic Energy Sciences Workshop on Solar Energy Utilization sponsored by the U.S. Department of Energy. Crabtree and Lewis served as co-chairs of the workshop and principal editors of the report. The key conclusions of the report identified opportunities for higher solar energy efficiencies in the areas of:

Electricity – important research developments lie in the development of new, less expensive materials for solar cells, including organics, thin films, dyes and shuttle ions, and in understanding the dynamics of charge transfer across nanostructured interfaces.

Fuel – solar photons can be converted into chemical fuel more resourcefully by breeding or genetically engineering designer plants, connecting natural photosynthetic pathways in novel configurations and using artificial bio-inspired nanoscale systems.
Heat – controlling the size, density and distribution of nanodot inclusions during bulk synthesis could enhance thermoelectric performance and achieve more reliable and inexpensive electricity production from the sun’s heat.

The nation’s first national laboratory, Argonne National Laboratory conducts basic and applied scientific research across a wide spectrum of disciplines, ranging from high-energy physics to climatology and biotechnology. Since 1990, Argonne has worked with more than 600 companies and numerous federal agencies and other organizations to help advance America’s scientific leadership and prepare the nation for the future. Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.

From Argonne National Laboratory

It’s the year 2020, and space has never been so busy. Picture this:

In Earth orbit, a robotic maintenance ship skitters from one weather satellite to another, upgrading powerful optics that help meteorologists track dangerous storms.

Four hundred thousand kilometers away, a cargo ferry arrives at the Moon. It spots an orbiting depot, makes its approach and mates flawlessly, offloading drill heads, solar panels and other supplies for a frontier outpost at the Moon’s south pole.

Meanwhile, down on the the lunar surface, mining buggies trundle along a “sensor highway” between the outpost and some nearby hills. They’re harvesting lunar ice hidden in the shadows of a deep, cold crater.

Oh yeah – there’s not a single human operator in this hypothetical scenario.

It’s not as far-out as it sounds. All of these spacecraft and satellites, even the mining buggies, could one day operate on their own, guided not by humans but by automated rendezvous and docking technologies now in development by NASA and its partners.

Some of those technologies are about to get a field test onboard Orbital Express–a space mission managed by the Defense Advanced Research Projects Agency (DARPA) and a team led by engineers at NASA’s Marshall Space Flight Center. Slated for launch this week, March 8, on an Atlas V rocket, Orbital Express will deploy two test satellites: the Autonomous Space Transport Robotic Operations (ASTRO) service vehicle, and the Next-generation serviceable satellite (NextSat).

“Our goal is to demonstrate on-orbit refueling, component exchange and satellite repair–all without a human operator,” says James Lee, the MSFC Automated Rendezvous and Docking Projects Lead.

In a nutshell, ASTRO will dock with NextSat and service it.

Who will pilot ASTRO? The answer is not who but what: the Advanced Video Guidance Sensor or AVGS for short. Mounted on ASTRO, the AVGS shoots infrared laser beams, which bounce off a pattern of retroreflectors on NextSat. By analyzing the reflections, ASTRO adjusts its speed and angle of approach to safely close the distance and make contact.

Eight test series will be conducted during the three-month mission. ASTRO and NextSat will conduct approach and docking maneuvers from starting points up to 4.3 miles (6.9 km) away. Once docked, they’ll also swap propellants and trade and install batteries–the first unassisted component exchange in space history. Tests will be conducted at different times of day to see if darkness on Earth’s night side confuses the imaging system.

If Orbital Express is a success, use of autonomous rendezvous and docking systems could become a viable alternative to human-piloted missions in the next decade.

“Automated systems will take ship-to-ship mating duties off the hands of busy flight crews,” says AVGS flight software project leader Keith Cornett of Marshall. “They can solve issues associated with tricky repairs and provide cost-effective options for servicing permanent satellites in orbit around the Moon or Mars.”

Automated systems could also benefit surface operations, Lee notes, particularly on the airless moon where global positioning systems won’t work without relays. That “sensor highway,” dotting the surface with reflective markers to shine the way, could one day guide robots from place to place – surveying, sampling and laying the groundwork for human expeditions to come.

“When it comes to exploring new worlds, robots can’t beat human beings for capturing the experience,” Lee says. “But to make those human missions possible, we need to set the stage as completely as we can. Automation is crucial.”

From NASA

In the digital age, organizing a photo collection has gone from bad to worse. The saying used to be that a picture is worth a thousand words. Now the question arises: what are a thousand pictures worth?In the digital age, organizing a photo collection has gone from bad to worse. The saying used to be that a picture is worth a thousand words. Now the question arises: what are a thousand pictures worth?

In a word, mainly a headache.

“Anyone who has a digital camera has the problem that they have more photos than they can possibly navigate,” says Steve Seitz, associate professor of computer science & engineering. “And it’s always a problem to find the photo that you’re looking for.”

Now experimental software developed by UW and Microsoft computer scientists, called Photo Tourism, turns the surfeit of images into a benefit. Hundreds of photos of a single scene can be mapped into a 3-D virtual world. The technology has potential not just for organizing photo collections, but for capturing scenes and, perhaps someday, creating a visual map of all the photos on the Internet.

Over the past year the research has catapulted to the marketplace. Early work attracted attention in March at Microsoft’s TechFest meeting. The project again made headlines in August when it was presented at a major graphics conference. Microsoft Live Labs signed a commercial license for the prototype software last August. Within a few months the company shipped a technology preview of a product that it called Photosynth.

“It’s been great to see a lot of people excited about it, and it’s also been a thrill to just have something, especially so quickly, that people could look at and use,” says doctoral student Noah Snavely. While Photosynth follows its own trajectory, Snavely will continue to develop Photo Tourism for his doctoral thesis, in collaboration with Seitz, an expert in computer vision, and Rick Szeliski, an employee at Microsoft Research and affiliate professor at the UW.

Snavely arrived from the University of Arizona three years ago interested in researching computer graphics. His target was not just personal photos collections but massive online collections, such as on the popular photo-sharing Web site Flickr. Members’ contributions to Flickr now total more than 200 million images.

“I was kind of inspired by that,” Snavely says.

If you type “Trevi Fountain” in Flickr’s search box, you will find more than 11,000 photos. Browsing through these photos means clicking through page after page of miniature pictures. Anyone who’s performed an image search on Google can appreciate the frustration. Finding a photo similar to what you need still won’t bring you any closer to the perfect shot.

“You might look at a photo and say I wonder what’s just to the left of it, or I wonder what’s just to the right of it, or I wish I could expand the field of view,” Snavely explains. It’s a challenge just to find the same scene taken at different times of the day. Trevi Fountain was the test case. (Snavely has never been there, though by now he’s seen it from almost every angle.) Later experiments used scenes of Notre Dame Cathedral in Paris and Half Dome mountain in Yosemite National Park.

To solve the problem, the researchers harnessed recent advances in computer vision research. They wrote computer software that analyzes each image and calculates where it was taken. To do this, the software looks for small details shared between different photos that can be used to compare them and stitch them together in three dimensions. Each photo is then represented by a small square placed in the appropriate position in a sketch of the original scene.

The effect is that you’re sifting through hundreds or thousands of photos, but it feels more like a video game. By moving right or left, or zooming in and out, the computer will fade to an appropriate shot. Highlighting a feature, like Neptune statue at the center of Trevi Fountain, brings up a high-resolution photo of that object.

This software goes beyond simply organizing a photo collection, Seitz says. It recreates a particular scene or location at the resolution of the photos. Real estate agencies, museums and hotels might find it a useful way to present a virtual tour because viewers could zoom in to read a restaurant menu or to view a painting. Archaeologists and biologists have expressed interest in creating realistic visual representations of their research sites. Military and surveillance organizations also would like to organize photographs in an intuitive way. Sports enthusiasts could even recreate their favorite game by combining all the photos taken at an event.

The current interface presents each photo as a little box, and photos fade into one another to give the impression of a 3-D zoom. Current research will create an even “more fluid, game-like interface,” Seitz says. Users will feel as if they are navigating a 3-D world.

Companies such as Google and Microsoft recently have begun to create 3-D models of cities by painstakingly gathering photos taken from different angles and then stitching them together. Photo Tourism doesn’t feel as smooth — there are gaps, and people sometimes pop up in the photos — but in the long term this ad-hoc method for combining photos taken at varying scales may offer advantages.

“I think it has the possibility to be much, much richer than just a static 3-D model,” Snavely says.

The most promising application for Photo Tourism, he believes, may be organizing the millions of photos that exist on the Internet. Snavely describes the concept as a “visual Wikipedia.” Contributors could upload photos and the program would combine them to create an increasingly comprehensive picture of the world. Combining the photos with a digital map like Google Earth would mean users could keep zooming in closer without the image ever going fuzzy.

But scaling up to handle millions of photos is still a ways off, Seitz says. “That’s another major research project.”

From University of Washington