Posted on by Fraser Cain

Shuttle Exhaust Can Make Clouds in Antarctica

Space shuttle Discovery on the launch pad. Image credit: NASA. Click to enlarge.
A new study, funded in part by the Naval Research Laboratory and the National Aeronautics and Space Administration (NASA) reports that exhaust from the space shuttle can create high-altitude clouds over Antarctica mere days following launch, providing valuable insight to global transport processes in the lower thermosphere[mhs1]. The same study also finds that the shuttle’s main engine exhaust plume carries small quantities of iron that can be observed from the ground, half a world away.

The international team of authors of the study, to appear in the July 6 issue of Geophysical Research Letters, used the STS-107 Shuttle mission as a case study to show that exhaust released in the lower thermosphere, near 110 kilometers altitude, can form Antarctic polar mesospheric clouds (PMCs). The thermosphere is the highest layer in our atmosphere, with the mesosphere (between 50-90 kilometers above the Earth), stratosphere, and troposphere below.

New observations presented by the research team from the Global Ultraviolet Imager (GUVI) on NASA’s Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite reveal transport of the STS-107 exhaust into the southern hemisphere just two days after the January 2003 launch. Water from the exhaust ultimately led to a significant burst of PMCs during the 2002-2003 southern polar summer, observed by the Solar Backscatter Ultraviolet (SBUV) satellite experiment. The inter-hemispheric transport followed by Antarctic PMC formation were unexpected.

PMCs, also known as noctilucent clouds, appear near 83 kilometers altitude and are made up of water ice particles created through microphysical processes of nucleation, condensation, and sedimentation. They typically appear in the frigid polar summer mesosphere where temperatures plummet below 130? Kelvin (-220? F). Little is known about the specific processes that lead to PMC formation.

According to the study’s lead author, Dr. Michael Stevens, a research physicist at the E.O. Hulburt Center for Space Research at the Naval Research Laboratory, the research produced multiple groundbreaking science results.

“This research is exciting in that it extends a new explanation for the formation of these clouds by demonstrating the global effect of a Shuttle exhaust plume in a region of the atmosphere that has traditionally not been well understood,” said Stevens.

Some believe that the impact of anthropogenic change in the lower atmosphere is reflected in these upper atmospheric clouds. Although historically PMCs have only been seen in the polar region, in recent years PMCs have been spotted at lower latitudes as far south as [mhs2]Colorado and Utah, renewing interest and sparking debate on the implications. However, the findings of this work, “call into question the interpretation of the impact of late 20th century PMC trends solely in terms of global climate change,” Stevens said. The team concludes that the water from a space shuttle’s exhaust plume can contribute a remarkable 10-20 percent to PMCs observed during one summer season in Antarctica.

A key piece of data that confirmed the plume’s arrival in Antarctica was the ground-based observation of iron atoms near 110 km. The presence of iron at this altitude originally perplexed scientists because there is no known natural source there. The data imply that iron ablated, or vaporized, by the main engines of the Shuttle was transported along with the water plume, arriving in Antarctica three to four days after the January 2003 launch. Both the water plume and the presence of iron demonstrate that the mean southward wind inferred from the team’s data is much faster than gleaned from global circulation models or wind climatologies.

“This tells us something new and exciting about transport in this region of the atmosphere,” said Stevens. “It can be so fast that a shuttle plume can form ice over Antarctica before other loss processes can really take effect. We must take great care in interpreting the long-term implications to observations and features of these clouds because of this contribution from the shuttle and the potential contribution from many other smaller launch vehicles.”

NRL and NASA funded the study, with contributions from the National Science Foundation, the British Antarctic Survey in Cambridge, United Kingdom, and the University of Illinois, Urbana-Champaign. Other researchers on the study include Robert Meier of George Mason University, Fairfax, Va.; Xinzhao Chu of the University of Illinois, Urbana-Champaign; Matthew DeLand of Science Systems & Applications, Inc., Lanham, Md.; and John Plane of the University of East Anglia, Norwich, United Kingdom.

Original Source: NRL News Release

Posted on by Fraser Cain

Microquasar Puzzles Astronomers

Computer illustration of microquasar LS5039. Image credit: PPARC. Click to enlarge.
In a recent issue of Science Magazine, the High Energy Stereoscopic System (H.E.S.S.) team of international astrophysicists reports the discovery of another new type of very high energy (VHE) gamma ray source.

Gamma-rays are produced in extreme cosmic particle accelerators such as supernova explosions and provide a unique view of the high energy processes at work in the Milky Way. VHE gamma-ray astronomy is still a young field and H.E.S.S. is conducting the first sensitive survey at this energy range, finding previously unknown sources.

The object that is producing the high energy radiation is thought to be a ‘microquasar’. These objects consist of two stars in orbit around each other. One star is an ordinary star, but the other has used up all its nuclear fuel, leaving behind a compact corpse. Depending on the mass of the star that produced it, this compact object is either a neutron star or a black hole, but either way its strong gravitational pull draws in matter from its companion star. This matter spirals down towards the neutron star or the black hole, in a similar way to water spiraling down a plughole.

However, sometimes the compact object receives more matter than it can cope with. The material is then squirted away from the system in a jet of matter moving at speeds close to that of light, resulting in a microquasar. Only a few such objects are known to exist in our galaxy and one of them, an object called LS5039, has now been detected by the H.E.S.S. team.

In fact, the real nature LS5039 is something of a mystery. It is not clear what the compact object is. Some of the characteristics suggest it is a neutron star, some that it is a black hole. Not only that, but the jet isn’t much of a jet; although it is moving at about 20% of the speed of light, which might seem a lot, in the context of these objects it’s actually quite slow.

Nor is it clear how the gamma rays are being produced. As Dr. Guillaume Dubus of the Ecole Polytechnique points out “We really shouldn’t have detected this object. Very high energy gamma rays emitted close to the companion star are more likely to be absorbed, creating a matter/antimatter cascade, than escape from the system.”

Dr Paula Chadwick of the University of Durham adds “It’s very exciting to have added another class of object to the growing catalogue of gamma ray sources. It’s an intriguing object – it will take more observations to work out what is going on in there.”

The H.E.S.S. array is ideal for finding new VHE gamma ray objects; because it’s wide field of view (ten times the diameter of the Moon) means that it can survey the sky and discover previously unknown sources.

The results were obtained using the High Energy Stereoscopic System (H.E.S.S.) telescopes in Namibia, in South-West Africa. This system of four 13 m diameter telescopes is currently the most sensitive detector of VHE gamma-rays – radiation that is a million, million times more energetic than the visible light. These high energy gamma rays are quite rare even for relatively strong sources; only about one gamma ray per month hits a square metre at the top of the Earth’s atmosphere. Also, since they are absorbed in the atmosphere, a direct detection of a significant number of the rare gamma rays would require a satellite of huge size. The H.E.S.S. telescopes employ a trick – they use the atmosphere as detector medium. When gamma rays are absorbed in the air, they emit short flashes of blue light, named Cherenkov light, lasting a few billionths of a second. This light is collected by the H.E.S.S. telescopes with large mirrors and extremely sensitive cameras and can be used to create images of astronomical objects as they appear in gamma-rays.

The H.E.S.S. telescopes represent several years of construction effort by an international team of more than 100 scientists and engineers from Germany, France, the UK, Ireland, the Czech Republic, Armenia, South Africa and the host country Namibia. The instrument was inaugurated in September 2004 by the Namibian Prime Minister, Theo-Ben Guirab, and its first data have already resulted in a number of important discoveries, including the first astronomical image of a supernova shock wave at the highest gamma-ray energies.

Original Source: PPARC News Release

Posted on by Fraser Cain

Seas are Rising Faster than Ever

Artist illustration of NASA satellite measuring sea levels. Image credit: NASA/JPL. Click to enlarge.
For the first time, NASA has the tools and expertise to understand the rate at which sea level is changing, some of the mechanisms that drive those changes and the effects that sea level change may have worldwide.

“It’s estimated that more than 100 million lives are potentially impacted by a one-meter (3.3-foot) increase in sea level,” said Dr. Waleed Abdalati, head of the Cryospheric Sciences Branch at NASA’s Goddard Space Flight Center, Greenbelt, Md. “When you consider this information, the importance of learning how and why these changes are occurring becomes clear,” he added.

Although scientists have directly measured sea level since the early part of the 20th century, it was not known how many of the observed changes in sea level were real and how many were related to upward or downward movement of the land. Now satellites have changed that by providing a reference by which changes in ocean height can be determined regardless of what the nearby land is doing. With new satellite measurements, scientists are able to better predict the rate at which sea level is rising and the cause of that rise.

“In the last 50 years sea level has risen at an estimated rate of .18 centimeters (.07 inches) per year, but in the last 12 years that rate appears to be .3 centimeters (.12 inches) per year. Roughly half of that is attributed to the expansion of ocean water as it has increased in temperature, with the rest coming from other sources,” said Dr. Steve Nerem, associate professor, Colorado Center for Astrodynamics Research, University of Colorado, Boulder.

Another source of sea level rise is the increase in ice melting. Evidence shows that sea levels rise and fall as ice on land grows and shrinks. With the new measurements now available, it’s possible to determine the rate at which ice is growing and shrinking.

“We’ve found the largest likely factor for sea level rise is changes in the amount of ice that covers the Earth. Three-fourths of the planet’s freshwater is stored in glaciers and ice sheets or the equivalent of about 67 meters (220 feet) of sea level,” said Dr. Eric Rignot, principal scientist for the Radar Science and Engineering Section at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Ice cover is shrinking much faster than we thought, with over half of recent sea level rise due to the melting of ice from Greenland, West Antarctica’s Amundsen Sea and mountain glaciers,” he said.

Additionally, NASA scientists and partner researchers now are able to measure and monitor the world’s waters globally in a sustained and comprehensive way using a combination of satellite observations and sensors in the ocean. By integrating the newly available satellite and surface data, scientists are better able to determine the causes and significance of current sea level changes.

“Now the challenge is to develop an even deeper understanding of what is responsible for sea level rise and to monitor for possible future changes. That’s where NASA’s satellites come in, with global coverage and ability to examine the many factors involved,” said Dr. Laury Miller, chief of the National Oceanic and Atmospheric Administration Laboratory for Satellite Altimetry, Washington, D.C.

NASA works with agency partners such as the National Oceanic and Atmospheric Administration and the National Science Foundation to explore and understand sea level change. Critical resources that NASA brings to bear on this issue include such satellites as:

— Topex/Poseidon and Jason, the U.S. portions of which are managed by JPL, which use radar to map the precise features of the oceans’ surface, measuring ocean height and monitoring ocean circulation;

— Ice, Cloud and Land Elevation Satellite (IceSat), which studies the mass of polar ice sheets and their contributions to global sea level change;

— Gravity Recovery And Climate Experiment (Grace), also managed by JPL, which maps Earth’s gravitational field, allowing us to better understand movement of water throughout the Earth.

Original Source: NASA News Release

Posted on by Fraser Cain

STS-114 Countdown Begins July 10

Space shuttle Discovery moving from the Vehicle Assembly building. Image credit: NASA. Click to enlarge.
NASA will begin the countdown for the Return to Flight launch of Space Shuttle Discovery on mission STS-114 July 10 at 6 p.m. EDT, 43 hours before liftoff. Discovery’s seven-member crew will test new equipment and procedures to increase the safety of the Shuttle and deliver spare parts, water and supplies to the International Space Station.

The Kennedy Space Center (KSC) launch team will conduct the countdown from Firing Room 3 of the Launch Control Center. The countdown includes nearly 27 hours of built-in hold time leading to a preferred launch time at about 3:51 p.m. on July 13 with a launch window extending about five minutes.

This historic mission is the 114th Space Shuttle flight and the 17th U.S. flight to the International Space Station. STS-114 is scheduled to last about 12 days with a planned KSC landing at about 11:01 a.m. EDT on July 25.

Discovery rolled into KSC’s Orbiter Processing Facility (OPF) on Aug. 22, 2001, after returning from its last mission STS-105 in August 2001 and undergoing an Orbiter Major Modification period. The Shuttle rolled out of OPF bay 3 and into the Vehicle Assembly Building (VAB) on March 29. While in VAB high bay 1, Discovery was mated to its redesigned External Tank and Solid Rocket Boosters. The entire Space Shuttle stack was transferred to Launch Pad 39B on April 7.

In order to allow for the addition of a new heater to the External Tank, Space Shuttle Discovery was rolled back to the VAB on May 26 for that modification to be performed. Discovery was removed from its External Tank and attached to a new tank originally scheduled to fly with orbiter Atlantis on mission STS-121, the second Return to Flight mission.

Discovery was rolled back out to Launch Pad 39B on June 15 in preparation for the July launch window.

On mission STS-114, the crew will perform inspections on orbit for the first time of all of the Reinforced Carbon-Carbon (RCC) panels on the leading edge of the wings and the Thermal Protection System tiles using the new Canadian-built Orbiter Boom Sensor System and the data from 176 impact and temperature sensors. Mission Specialists will also practice repair techniques on RCC and tile samples during a spacewalk in the payload bay.

In the payload bay, the Multi-Purpose Logistic Module Raffaello, built by the Italian Space Agency, will carry 11 racks with supplies, hardware, equipment and the Human Research Facility-2.

During two additional spacewalks, the crew will install the External Stowage Platform-2, equipped with spare part assemblies, and a replacement Control Moment Gyroscope contained in the Lightweight Multi-Purpose Experiment Support Structure.

The STS-114 crew includes Commander Eileen Collins, Pilot James Kelly, and Mission Specialists Soichi Noguchi, Stephen Robinson, Andrew Thomas, Wendy Lawrence and Charles Camarda.

Original Source:NASA News Release

Posted on by Fraser Cain

Extremely Large Telescope Takes the Next Step

Astronomers from across Europe today (July 7th) took a step closer to making their plans for a giant telescope a reality when they unveiled the scientific case for an Extremely Large Telescope (ELT) – a monster telescope with a light capturing mirror of between 50 and 100 metres, dwarfing all previous optical telescope facilities. The announcement was made at a meeting in Dwingeloo, the Netherlands and initiates the design phase of the project. Astronomers plan to use the ELT to search for planets like the Earth in other star systems and to find out when the first stars in the Universe began to shine.

The first step when selecting the specifications and design options for a new telescope is for astronomers to establish the science that could be achieved with the facility. The science case launched today will be used in a Design Study funded by the European Union’s Framework 6 Programme and a Europe-wide consortium of partners, including industry, aimed at evaluating critical technologies needed to build a giant telescope, and led by the European Southern Observatory (ESO). The UK part of this ?30M programme is led by the UK Astronomy Technology Centre (UK ATC) and partly funded by the Particle Physics and Astronomy Research Council (PPARC).

Roberto Gilmozzi, ESO’s coordinator of the ELT Design Study said, “The ELT Design Study initiative, a 31 MEuro activity partially funded by the FP6, shows the willingness of Europe to pursue a common path towards the eventual construction of an ELT. It is a design independent study of enabling technologies that brings together European institutes and industry to define a palette of ELT “building blocks” that indicate the way in which the telescope design should evolve to take advantage of the directions industry believes are most appropriate and cost effective.”

Bigger is better

The power of optical telescopes is limited by the size of the mirror that is used to collect light, which in turn determines how well they can distinguish between faint objects – the bigger the mirror, the fainter the object that the telescope will be able to see. For example, a 100m telescope with perfect compensation for atmospheric disturbances would be able to separate two points on the moon two metres apart, compared with 95m apart for the Hubble Space Telescope.

The quest for bigger mirrors has pushed current technologies to their limits. Some of the most advanced 8-10 metre telescopes now rely on mirrors constructed from smaller mirror segments, controlled by computers to act as a single large surface. These new techniques offer astronomers the opportunity for an unprecedented step-up in size. A 100m telescope would use a greater area of precision mirrors than has been made for all the previous telescopes ever built!

Dr Isobel Hook from the University of Oxford has led the working group producing the science case. She says “An Extremely Large Telescope is a very exciting prospect for astronomers. Something with a 50 or even 100 metre mirror could completely change our understanding of the Universe and answer truly fundamental questions such as ‘Is the Earth unique?’ and ‘How did the first stars and galaxies form?’. We will have much more information than ever before – it will be a bit like being there when the first telescopes were pointed at the sky.”

The next step

The European ELT Design Study is a five year project to explore the challenges of building an ELT, with most of the work being done in the initial three years. Every aspect of the ELT project will be examined, from site selection to instrumentation. It is due to report in 2008 at which time it will present a range of options to funding agencies.

The design study will provide the crucial technical information needed to make tough decisions at the next stage. This will involve balancing the size and design of the telescope against cost and time of first operation. Building work is likely to start in the next decade and the telescope could start scientific operations from 2015!

Professor Gerry Gilmore of the Institute of Astronomy Cambridge and Chair of the EU OPTICON network, said “Development of the ELT science case has involved over 100 European astronomers, and 3 years of work. All this happened because the astronomers want it: an ELT is overwhelmingly the scientifically favoured next major astronomy development, with widespread and strong community support. Turning this bottom-up support into a science case and a design study proposal needed some resources, and a trans-national support structure, both naturally available and provided by the EC-funded OPTICON infrastructure network. This proves that European astronomers are becoming a single community, and as such are now international leaders in astronomy.”

PPARC, the UK funding agency for astronomy, has earmarked ?2million for research and development of an ELT for the period to April 2008. ?500,000 of this is to support the design study concentrating on UK strengths in instrumentation and adaptive optics led by the UK ATC, in partnership with Durham and Oxford Universities. The remainder of the programme is under evaluation, but will concentrate on key technologies such as lightweight and adaptive mirrors to enable the science goals to be met at an affordable cost.

Colin Cunningham, Director of Technology Development at the UK ATC says “A telescope of 50 to 100m in diameter will have outstanding sensitivity and resolution -but to reach this performance at an affordable cost requires us to address many engineering and technology challenges. The UK will be at the heart of these efforts through its part in the EU-supported ELT Design Study and our UK R&D programme which will bring together academic and industrial partners in preparation for the design and construction phase of this exciting project.”

Original Source: PPARC News Release

Posted on by Fraser Cain

Gemini Sees Rocky Material on Tempel 1

False colour image of Tempel 1 taken by Gemini North. Image credit: Gemini. Click to enlarge.
The Gemini North telescope on Mauna Kea successfully captured the dramatic fireworks display produced by the collision of NASA’s Deep Impact probe with Comet 9P/Tempel 1. Researchers in two control rooms on Hawaii?s Big Island (on Mauna Kea and in Hilo) were able to keep enough composure amid an almost giddy excitement to perform a preliminary analysis of the data. They concluded from the mid-infrared spectroscopic observations that there was strong evidence for silicates or rocky material exposed by the impact. Little doubt remains that the unprecedented quality of the Gemini data will keep astronomers busy for years.

?The properties of the mid-infrared light were completely transformed after impact,? said David Harker of the University of San Diego, co-investigator for the research team. ?In addition to brightening by a factor of about 4, the characteristics of the mid-infrared light was like a chameleon and within five minutes of the collision it looked like an entirely new object.? Harker?s research partner Chick Woodward of the University of Minnesota speculated further, ?We are possibly seeing crystalline silicates which might even be similar to the beach sand here in Hawaii! This data will keep us busy trying to figure out the size and composition of these grains to better understand the similarities and differences between the material contained within comets and other bodies in the solar system.?

In addition to the spectroscopic observations, before-and-after images were also obtained by the Gemini telescope in thermal infrared light and can be seen in Figure 1. Gemini monitored the comet for several weeks prior to the impact and will continue to watch it through the end of July.

The Gemini observations were part of a coordinated effort between the W.M. Keck, Subaru and Gemini Observatories so that each could concentrate on different observations and provide a complete, complementary ?picture? of the impact. Astronomers anticipate that the data gathered from the largest and most sophisticated set of telescopes positioned to see the impact will add considerably to our understanding of comets as dynamic probes of our solar system?s early evolution some 4.5-5 billion years ago.

The Gemini observations were made using Michelle, the facility mid-infrared imager/spectrograph built at the Royal Observatory of Edinburgh (ROE) in the UK. The instrument has unique capabilities in the mid-infrared especially at Gemini which uses protected silver coatings on main mirrors to provide exceptional performance in the ?thermal? or mid-infrared part of the spectrum.

Original Source: Gemini Observatory News Release

Posted on by Fraser Cain

Layers of Minerals Tell the History of Mars

Panoramic view of Mars taken by NASA’s Spirit rover. Image credit: NASA/JPL. Click to enlarge.
Mars is a rocky planet with an ancient volcanic past, but new findings show the planet is more complex and active than previously believed – at least in certain places.

Finding those places, however, turns out to be trickier than just looking at landforms like river valleys or lakebeds or searching for specific minerals.

“Context is everything,” said Philip Christensen, Principal Investigator for the Thermal Emission Spectrometer (TES) on Mars Global Surveyor and for the Thermal Emission Imaging System (THEMIS) on Mars Odyssey, as well as lead scientist for the Mini-TES instruments on the Mars Exploration Rovers. “There has been a lot of excitement about finding specific features or minerals, but THEMIS, together with the TES infrared spectrometer, is giving us an overview by finding all the minerals. It gives us context – the underlying geology of the place.”

A paper led by Christensen, to be released online by the journal Nature on July 6, describes how a detailed examination of the Red Planet’s surface minerals using THEMIS and TES data yields surprising results in certain localized areas.

While the current rover missions have largely proved that in the distant past Mars may have had a lake or two, several different orbital mapping missions have found a basalt-rich planet that is the product of an ancient volcanic history. Geologically, it seems like a simple planet in the large scale – but then there are local windows showing far more complexity.

“From what we have seen to date, you might imagine going to Mars and seeing nothing but basalt,” said Christensen. “The evidence has always shown that the planet was active early, made some big volcanoes and then shut down and that was that. But when we looked more carefully we saw that there are these other places?When you look at the geology in the right spots, there is as much diversity in the rocks as you see on Earth.

“Once you get a glimpse of this complexity, you realize that there is a very complex world underneath that veneer of basalt.”

What Christensen and team found were localized deposits showing a distribution of igneous mineral types rivaling the range of minerals found on Earth – from primitive volcanic rocks like olivine-rich basalts to highly processed silica-rich rocks like granites.

The diversity of igneous minerals is important, Christensen explains, because it implies that the surface rocks have continued to be processed and reconstituted multiple times over an extended period of time.

“You melt the mantle and you get olivine basalts; you melt them again and you get basalt; you melt that and you make andesite; you melt that and you make dacite; you melt that and you make granite,” said Christensen. “Every time you re-melt a rock, the first thing to come off is the silica, so each time you melt it, you’re refining the silica.”

On Earth, such mineral evolution generally occurs as primitive volcanic rocks get folded back into the planet’s crust, re-melted and refined as faster melting components like silica separate out of the original material – a process known as mineral fractionation.

Mars, unlike Earth, does not have moving plates recycling the planet’s crust. However, Christensen’s results show that, like Earth, Mars has evolved and may still be evolving beneath the surface.

“Mars is a more complicated planet than we thought – the geology has kept chugging along and evolving over time,” Christensen said. “Though they’re not widespread, we’ve found dacite, and we’ve found granite. One way to make these granites is to make a whole volcano stacked up out of basalt – it gets tall enough and you begin to remelt the stuff deep down, and when you remelt the basalt, you can have granites forming.

“These are fairly small occurrences. On Earth, we have mountain ranges made of granite, on Mars we have so far only found a couple of globs. It’s not like the Earth in the extent of this geological evolution, but Mars is like the Earth in localized situations. It’s been hidden from us, but it’s a sophisticated, evolving planet after all,” he said.

Because the areas where the evolved igneous rocks occur are small, it has taken the high-resolution multispectral camera in Mars Odyssey’s THEMIS instrument (with a resolution of 100 meters) to find the minerals from orbit by finding a specific infrared signature in specific landforms. THEMIS’s mineral mapping has been 1500 times more detailed than TES’s, though the TES instrument’s infrared spectrometer (with a resolution of 3 kilometers) detects a much more detailed range of infrared emissions, making it more sensitive to different mineral compositions.

“We’re doing the thing that we set out to do: mapping the composition at mesoscales,” Christensen noted. “THEMIS identifies the area, then we go back and find what may be just a single, over-looked TES pixel and analyze it. The two were really planned to work together and that’s exactly what we’ve been doing. We use these two instruments in a synergistic way and together they’re perfect.”

Though Mars mapping has been going on for many years, Christensen notes that some of the most interesting places on the planet have yet to be identified and explored.

“If you drained the Earth’s oceans and looked at it from space, you would probably reach the same conclusion – a quiet, basaltic planet,” he said. “But then, if you searched carefully, you might find Yellowstone and realize that there was a lot going on below the surface of the planet that you weren’t aware of. We’re at that stage now in looking at Mars.”

Original Source: NASA Astrobiology

Posted on by Fraser Cain

Swift’s Take on Deep Impact

Swift’s view of Comet Tempel 1. Image credit: PSU. Click to enlarge.
Scientists using the Swift satellite witnessed a tale of fire and ice today, as NASA’s Deep Impact probe slammed into the frozen comet Tempel 1. The collision briefly lit the dim comet’s surface and exposed, for the first time, a section of ancient and virgin material from the comet’s interior.

Swift is providing the only simultaneous multi-wavelength observation of this rare event, with a suite of instruments capable of detecting optical light, ultraviolet, X-rays and gamma rays. Different wavelengths reveal different secrets about the comet.

So far, after a set of eight observations each lasting about 50 minutes, Swift scientists have seen a quick and dramatic rise in ultraviolet light, evidence that the Deep Impact probe struck a hard surface, as opposed to a softer, snowy surface.

More observations and analysis are expected in the coming days from teams at NASA and Penn State and in Italy and the United Kingdom.

“We have now observed this comet before, during, and after the collision,” said Dr. Sally Hunsberger of the Swift Mission Operation Center at Penn State. “The comparison of observations at different times — that is, what was seen, when and at what wavelength — should prove to be quite interesting.”

Most of the debris observed in ultraviolet light likely came from once-icy surface material heated to 2,000 degrees by the impact. X-rays have not been detected yet but analysis will continue throughout the week. X-rays are expected to be emitted from newly liberated sub-surface material lifted into the comet’s coma, which is then illuminated by the high-energy solar wind from the Sun. It takes about a day, however, for the material to reach the coma.

“Some called it fireworks today, but it really was more like ‘iceworks,'” said Prof. Keith Mason, Director of Mullard Space Science Laboratory at University College London, who organized the Swift observations. “Much of the comet is ice. It’s the other stuff deep inside we’re most interested in — pristine material from the formation of the solar system locked safely below the comet’s frozen surface. We don’t know exactly what we kicked up yet.”

Swift’s “day job” is detecting distant, natural explosions called gamma-ray bursts and creating a map of X-ray sources in the universe, far more energetic “fireworks.” Indeed, since beginning this Deep Impact campaign on July 1 — in addition to seeing comet Tempel 1 — Swift has seen a gamma-ray burst and a supernova and has discovered a black hole in the Milky Way galaxy. The satellite’s speed and agility, however, provides an important complement to the dozens of other world-class observatories in space and on Earth observing the Deep Impact experiment. Swift will continue to monitor the comet this week.

Comets are small astronomical objects usually in highly elliptical orbits around the sun. They are made primarily of frozen water, methane and carbon dioxide with a small amount of minerals. They likely originate in the Oort Cloud in the outskirts of the solar system. Comet Tempel 1 is about the size of Washington, D.C. Some scientists say that comets crashing into Earth billions of years ago brought water to our planet.

A comet becomes visible when radiation from the Sun evaporates its outer layers, creating a coma, the thin atmosphere. Solar wind impacts the coma to form the comet’s tail of dust and gas, which always points away from the Sun. Comets are best visible when they enter the inner solar system, closer to the Sun.

“The Deep Impact collision was the most watched astronomical event of the year,” said Dr. Neil Gehrels, Swift Principal Investigator at NASA Goddard Space Flight Center in Greenbelt, Md. “All the ‘big-guns’ observatories tracked it. In the next few days, as material continues to fly off the comet from newly created vents, we will see whether Swift can offer new insight into comets by virtue of the high-energy light we are seeing.”

Prof. Mason and Prof. Alan Wells of the University of Leicester in England are at the Swift Mission Operation Center to help with the observation.

The Deep Impact mission is managed by NASA’s Jet Propulsion Laboratory, Pasadena, California. Swift is a medium-class NASA explorer mission in partnership with the Italian Space Agency and the Particle Physics and Astronomy Research Council in the United Kingdom, and is managed by NASA Goddard. Penn State controls science and flight operations from the Mission Operations Center in University Park, Pennsylvania. The spacecraft was built in collaboration with national laboratories, universities and international partners, including Penn State University; Los Alamos National Laboratory, New Mexico; Sonoma State University, Rohnert Park, Calif.; Mullard Space Science Laboratory in Dorking, Surrey, England; the University of Leicester, England; Brera Observatory in Milan; and ASI Science Data Center in Frascati, Italy.

Original Source: PSU News Release

Posted on by Fraser Cain

Solar Aircraft to Fly Around the World

Artist illustration of the Solar Impulse solar powered airplane. Image credit: ESA. Click to enlarge.
Swiss adventurer Bertrand Piccard is constructing a solar-powered plane to fly around the world. His aim is to support sustainable development by demonstrating what renewable energy and new technologies can achieve. ESA is assisting by making available European space technologies and expertise through its Technology Transfer Programme.

Bertrand Piccard made the first non-stop around the world balloon-flight in a Breitling Orbiter in 1999 with Brian Jones from Britain. Now together again, and with a team of 60 specialists, they are constructing an aircraft named Solar Impulse that will be powered only by sunlight.

“Solar Impulse will promote the idea of a new aviation era using cleaner planes powered by the almost infinite energy of the Sun rather than the dirty, finite reserves of fossil fuels,” says Bertrand Piccard.

“Although in its present design the craft will never be able to carry many passengers we believe that Solar Impulse can spark awareness about the technologies that can make sustainable development possible.”

ESA’s Technology Transfer Programme is providing technological expertise while the Swiss Federal Institute of Technology (EPFL) in Lausanne is the ‘Official Scientific Advisor’ for the project.

“The sun is the primary source of energy for our satellites as well as for Piccard’s plane. With the European space industry we have developed some of the most efficient solar cells, intelligent energy management systems and resourceful storage systems,” says Pierre Brisson, Head of ESA’s Technology Transfer Programme.

“We will make available this expertise, together with our advanced technologies, to support Piccard’s effort to demonstrate the potential of sustainable development.”

On its round the world flight, planned for 2010, the single-pilot Solar Impulse will be flown by three pilots flying in shifts: Bertrand Piccard, President and initiator of the project; Brian Jones, responsible for the sustainable development programme; and Andr? Borschberg from Switzerland, the Solar Impulse Chief Executive Officer.

The conceptual design is now in progress and a model of the plane was shown at the June Le Bourget air show. For the plane to be ready for flight in 2010 the following schedule must be kept:

* 2006-2007: detailed design and assembly of the plane
* 2008: first test flights and night flights
* 2009: solar flights of several days’ duration
* 2010 round-the-world flight

The round the world trip will take place in five stages, each of which will last three to five days. It will fly from west to east and between 10? and 30? north of the Equator to take advantage of the prevailing winds and sunlight.

Original Source: ESA News Release

Here’s an article about the biggest plane in the world.