Posted on by Fraser Cain

Icy Epimetheus

Icy Epimetheus behind Saturn’s rings. Image credit: NASA/JPL/SSI Click to enlarge
The Cassini spacecraft captured this glimpse of icy Epimetheus just before the small moon disappeared behind the bulk of Saturn’s atmosphere.

See Looking Down on Epimetheus for a closer view of Epimetheus (116 kilometers, or 72 miles across).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 20, 2005, at a distance of approximately 2.3 million kilometers (1.4 million miles) from Epimetheus and 2.2 million kilometers (1.4 million miles) from Saturn. The image scale is 14 kilometers (9 miles) per pixel on Epimetheus and 13 kilometers (8 miles) per pixel on Saturn.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Posted on by Fraser Cain

Predicting Titan’s Weather

False-colour images of Titan obtained by Cassini-Huygens Visual Infrared Mapping Spectrometer. Image credit: Click to enlarge
Using recent Cassini, Huygens and Earth-based observations, scientists have been able to create a computer model which explains the formation of several types of ethane and methane clouds on Titan.

Clouds have been observed recently on Titan, Saturn’s largest moon, through the thick haze, using near-infrared spectroscopy and images of the south pole and temperate regions near 40? South. Recent observations from Earth-based telescopes and the NASA/ESA/ASI Cassini spacecraft are now providing an insight into cloud climatology.

A European team, led by Pascal Rannou of the Service d?Aeronomie, IPSL Universite de Versailles-St-Quentin, France, has developed a general circulation model which couples dynamics, haze and cloud physics to study Titan climate and enables us to understand how the major cloud features which are observed, are produced.

This climate model also allows scientists to predict the cloud distribution for the complete Titan year (30 terrestrial years), and especially in the next years of Cassini observations.

The Voyager missions of the early 1980s gave the first indications of condensate clouds on Titan. Because of the cold temperatures in the moon?s atmosphere (tropopause), it was assumed that most of the organic chemicals formed in the upper atmosphere by photochemistry would condense into clouds while sinking. Methane would also condense at high altitudes, it was believed, having been transported from the surface.

Since then, several one-dimensional models of Titan’s atmosphere including sophisticated microphysics models were created to predict the formation of drops of ethane and methane. Similarly, the methane cycle had been studied separately in a circulation model, but without cloud microphysics.

These studies generally found that methane clouds could be triggered when air parcels cooled while moving upward or from equator to pole. However, these models hardly captured the fine details of the methane and ethane cloud cycles.

What Rannou’s team has done is to combine a cloud microphysical model into a general circulation model. The team can now identify and explain the formation of several types of ethane and methane clouds, including the south polar and sporadic clouds in the temperate regions, especially at 40? S in the summer hemisphere.

The scientists found that the predicted physical properties of the clouds in their model matched well with recent observations. Methane clouds that have been observed to date appear in locations where ascending air motions are predicted in their model.

The observed south polar cloud appears at the top of a particular ‘Hadley cell’, or mass of vertically circulating air, exactly where predicted at the south pole at an altitude of around 20-30 kilometres.

The recurrent large zonal (longitudinal direction) clouds at 40? S and the linear and discrete clouds that appear in the lower latitudes are also correlated with the ascending part of similar circulation cell in the troposphere, whereas smaller clouds at low latitudes, similar to the linear and discrete clouds already observed by Cassini are rather produced by mixing processes.

“Clouds in our circulation model are necessarily simplified relative to the real clouds, however the main cloud features predicted find a counterpart in reality.

“Consistently, our model produces clouds at places where clouds are actually observed, but it also predicts clouds that have not, or not yet, been observed,” said Pascal Rannou.

Titan’s cloud pattern appears to be similar to that of the main cloud patterns on Earth and Mars. The puzzling clouds at 40? S are produced by the ascending branch of a Hadley cell, exactly like tropical clouds are in the Intertropical Convergence Zone (ITCZ), as on Earth and Mars.

Polar clouds – produced by ‘polar cells’ – are similar to those produced at mid-latitudes on Earth. On other hand, clouds only appears at some longitudes. This is a specific feature of Titan clouds, and may be due to a Saturn tidal effect. The dynamical origin of cloud distribution on Titan is easy to test.

Cloudiness prediction for the coming years will be compared to observations made by Cassini and ground-based telescopes. Specific events will definitely prove the role of the circulation on the cloud distribution.

Original Source: ESA Portal

Posted on by Fraser Cain

NASA’s IMAGE Mission Ends

IMAGE launch on March, 2000. Image credit: NASA Click to enlarge
NASA’s Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite recently ceased operations, bringing to a close a successful six-year mission. IMAGE was the premier producer of new discoveries on the structure and dynamics of the Earth’s external magnetic field (magnetosphere) and its contents.

“The IMAGE mission showed us space around the Earth is anything but empty, and that plasma clouds can be imaged and tracked just as we do from space for Earth’s surface weather,” said Barbara Giles, IMAGE Program Scientist at NASA headquarters.

Prior to the launch of IMAGE, the energetic particles and electrically charged gas (plasma) surrounding the Earth were completely invisible to human observers. IMAGE enabled researchers to study the global structure and dynamics of the Earth’s inner magnetosphere as it responded to energy from solar winds.

“Nearly six years of imagery by the pioneering cameras on IMAGE revolutionized our understanding of geospace and our knowledge of its space weather,” said James Burch, IMAGE principal investigator at the Southwest Research Institute, San Antonio.

IMAGE was launched on March 25, 2000. It successfully completed its two-year primary mission and continued providing data into December 2005, when it stopped responding to commands from ground controllers. Preliminary analysis indicated the craft’s power supply subsystems failed, rendering it lifeless. The satellite is in an extended elliptical orbit and poses no threat to the planet.

IMAGE discoveries have been reported in more than 400 peer-reviewed publications. More than 20 Ph.D. theses were based on data from the mission. Science highlights include:

– Confirmations: plasma plume creation, post-midnight peak in storm plasmas, the neutral solar wind, terrestrial origin of geospace storm plasmas and continuous nature of magnetic reconnection.

– Discoveries: plasmaspheric shoulders and notches, proton auroras in unexpected places, surprisingly slow plasmasphere rotation, a hot oxygen geocorona and a secondary interstellar neutral atom stream.

– Resolutions: the source of kilometric continuum radiation, solar- wind and auroral intensity effects on ionospheric out flow and the relationship between proton and electron auroras during geospace storms.

The IMAGE education and public outreach program received numerous awards for videos, books, primary and secondary school curricula, teacher training, museum exhibits, planetarium shows, student workbooks and web-based information.

The extensive archival database generated by IMAGE promises to yield new discoveries and will support investigations by other spacecraft and ground-based observatories for many years.

IMAGE was a Medium Explorer mission sponsored by NASA’s Sun-Earth Connections Program and managed by NASA’s Goddard Space Flight Center, Greenbelt, Md. The Southwest Research Institute conducts IMAGE science operations. James Burch is the mission principal Investigator, and Thomas Moore at Goddard is the Mission Scientist.

For information about the IMAGE mission on the Web, visit:

http://image.gsfc.nasa.gov/

Original Source: NASA News Release

Posted on by Mark Mortimer

Book Review: Return to the Moon

The Apollo program of the 1960’s successfully placed a few military men and one geologist on the Moon’s surface. The goal of the program was to showcase the technology of the US. The result aimed for people around the world to believe that their style of government was better than communism. Since this propaganda event, the US, and indeed the rest of the world has, at best, placed a few more people in low earth orbit. Though a number of programs and concepts were dreamed of and even broadcasted, no funds were ever sent their way. Hence, since the highwater mark of landing on the Moon, people have remained in the relatively safe environs within the Earth’s radiation belt. Only a few robots and probes have gone farther to learn more. With over 30 years accumulated knowledge, many expect that it’s time to use this knowledge and get some return from our investment in space.

The desire to return comes out clear and strong in this book. There are twenty eight articles, each written by a motivated specialist. The common theme addresses the how and why of having people return to the Moon. With so many contributors, particular topics can get quite esoteric. Routine thoughts about launch vehicles are followed by more expansive articles on land ownership, rocket sleds, nanobot proving grounds and conscious evolution. As varied as the topics are, none reside in the realm of science fiction. Each has a sound basis in reason. And each, at least according to the author, would make a valuable contribution to this new program. Judicious editing by Tumlinson and Medlicott keep the articles clear, concise and relevant.

Given that both editors are board members of the Space Frontier Foundation, there is no surprise that the underlying theme of the book is for a greater frontier like attitude to Moon exploration. Given this viewpoint, there’s lots of NASA bashing and suggestions for improvements. The articles aren’t necessarily anti-establishment, the authors just believe that their ideas can improve that which has gone before. But, the authors can be overly optimistic. They seem to forget that during the frontier days there was lots of experimentation together with many accidental and purposeful deaths. This downside is never mentioned. Rather, the typical expectation shown in the articles is for the government to build the transportation infrastructure, as the railways in the old west. Once done, rich people or well funded corporations would use it in the time honoured practise of making profit. Maybe this approach will occur and succeed, maybe it won’t. However, this frontier approach is the only one supported within the book.

By having many different authors and many different angles, each article has its own style and flavour. Like an ice cream stand, there should be something for everyone. Also, the authors make convincing arguments. This leaves the impression is that they’ve argued their cases often and can support their reasoning. This robustness lends credence to individual theories and the underlying theme. Also, the topics flow with little repetition, aside from the berating of NASA though these can easily be skipped over. A preamble presumably written by one of the editors effectively places each article in the flow of the arguments. The editors did however miss a fair number of errors which takes some of the polish off. Nevertheless, if you’re interested in alternative options in getting people working on the Moon, this book has many articles which might strike your fancy.

Government programs are one of the few places where you can get away with spending other people’s money. Fun as it is, everyone from program managers on up the line must be able to substantiate the investment. Rick Tumlinson and Erin Medlicott in their book Return to the Moon bring together articles from many experts to add some options for the US government’s current program to place people again on the Moon and then on to Mars. The many ideas can bring a fresh new perspective to spending money and realizing profit from setting up a work place for humans off of Earth.

Review by Mark Mortimer

Read more reviews online, or purchase a copy from Countdown Creations.

Posted on by Fraser Cain

Icy Martian Glaciers

Perspective view of ‘hourglass’ shaped craters. Image credit: ESA Click to enlarge
The spectacular features visible today on the surface of the Red Planet indicate the past existence of Martian glaciers, but where did the ice come from?

An international team of scientists have produced sophisticated climate simulations suggesting that geologically recent glaciers at low latitudes (that is near the present-day equator) may have formed through atmospheric precipitation of water-ice particles.

Moreover, the results of the simulations show for the first time that the predicted locations for these glaciers match extensively with many of the glacier remnants observed today at these latitudes on Mars.

For several years, the presence, age and shape of these glacier remnants have raised numerous questions in the scientific community about their formation, and about the conditions on the planet when this happened.

To start narrowing down the rising number of hypotheses, a team led by Francois Forget, University of Paris 6 (France) and interdisciplinary scientist for ESA’s Mars Express mission, decided to ‘turn back the clock’ in their Martian global climate computer model, a tool usually applied to simulate the detail of present-day Mars meteorology.

As a starting point, Forget and colleagues had to make some assumptions – that the north polar cap was still the ice reservoir of the planet, and that the rotation axis was tilted by 45? with respect to the planet?s orbital plane.

“This makes the axis much more oblique than it is today (about 25?), but such an obliquity has probably been very common throughout Mars?s history. Actually, it last occurred only five and a half million years ago,” says Forget.

As expected with such a tilt, the greater solar illumination in the north polar summer increased the sublimation of the polar ice and led to a water cycle much more intense than today.

The simulations showed water ice being accumulated at a rate of 30 to 70 millimetres per year in a few localised areas on the flanks of the Elysium Mons, Olympus Mons and the three Tharsis Montes volcanoes.

After a few thousand years, the accumulated ice would form glaciers up to several hundreds of metres thick.

When the team compared the location and shape of the ‘simulated’ glaciers with the actual glacier-related deposits of Tharsis – one of the three main regions on the planet where signs of glaciers are seen – they found an excellent agreement.

In particular, the maximum deposition is predicted on the western flanks of the Arsia and Pavonis Montes of the Tharsis region, where the largest deposits in this area are actually observed.

In their simulations, the team could even ‘read’ why and how ice was accumulated on the flanks of these mountains in the Tharsis region millions of years ago.

Back then, constant year-long winds similar to monsoons on Earth would favour the upslope movement of water-rich air around Arsia and Pavonis Montes.

While being cooled down by tens of degrees, water would condense and form ice particles (larger than those we observe today in the Tharsis region’s clouds) that settled on the surface.

Other mountains like Olympus Mons show smaller-scale deposits because, according to the simulations, they were exposed to the monsoon-type strong winds and water-rich air only during the northern summer.

“The north polar cap may not have always been the only source of water during the planet’s high obliquity periods,” adds Forget.

“So we ran simulations assuming that ice was available in the south polar cap. We could still see ice accumulation in the Tharsis region, but this time also on the east of the Hellas Basin, a six-kilometre deep crater.”

This would explain the origins of another major area where ice-related landforms are observed today, the eastern Hellas Basin. indeed.

“The Hellas basin is in fact so deep as to induce the generation of a northward wind flow on its eastern side that would carry most of the water vapour sublimating from the south polar cap during summer. When the water-rich air meet colder air mass over eastern Hellas, water condense, precipitate, and form glaciers,” said Forget.

However, the team could not predict ice deposition in the Deuterolinus-Protonilus Mensae region, where glaciers could have been formed by other mechanisms. The scientists are considering several other hypotheses on the formation of recent glaciers.

For instance, observations of Olympus Mons by the High Resolution Stereo Camera on board Mars Express suggest that movement of water from the subsurface to the surface due to hydrothermal activity may have led to the development of glaciers on the cold surface.

Original Source: ESA Mars Express

Posted on by Fraser Cain

World’s Largest Telescope

An image of how one element of the SKA might look. Image credit: Chris Fluke. Click to enlarge
European funding has now been agreed to start designing the world’s biggest telescope. The “Square Kilometre Array” (SKA) will be an international radio telescope with a collecting area of one million square metres – equivalent to about 200 football pitches – making SKA 200 times bigger than the University of Manchester’s Lovell Telescope at Jodrell Bank and so the largest radio telescope ever constructed. Such a telescope would be so sensitive that it could detect TV Broadcasts coming from the nearest stars.

The four-year Square Kilometre Array Design Study (SKADS) will bring together European and international astronomers to formulate and agree the most effective design. The final design will enable the SKA to probe the cosmos in unprecedented detail, answering fundamental questions about the Universe, such as “what is dark energy?” and “how did the structure we see in galaxies today actually form?”.

The new telescope will test Einstein’s General Theory of Relativity to the limit – and perhaps prove it wrong. It is certain to add to the long list of fundamental discoveries already made by radio astronomers including quasars, pulsars and the radiation left over from the Big Bang. By the end of this decade the design will be complete and astronomers anticipate building SKA in stages, leading to completion and full operation in 2020.

The SKA concept was first proposed to observe the characteristic radio emission from hydrogen gas. Measurements of the hydrogen signature will enable astronomers to locate and weigh a billion galaxies.

As the University of Manchester’s Prof Peter Wilkinson points out, “Hydrogen is the most abundant element in the universe, but its signal is weak and so a huge collecting area is needed to be able to study it at the vast distances that take us back in time towards the Big Bang”. To which Prof Steve Rawlings, University of Oxford, adds,”The distribution of these galaxies in space tells us how the universe has evolved since the Big Bang and hence about the nature of the Dark Energy which is now making the universe expand faster with time”.

Another target for the SKA is pulsars – spinning remnants of stellar explosions which are the most accurate clocks in the universe. A million times the mass of the Earth but only the size of a large city, pulsars can spin around hundreds of times per second. Already these amazing objects have enabled astronomers to confirm Einstein’s prediction of gravitational waves, but University of Manchester’s Dr Michael Kramer is looking further ahead. “With the SKA we will find a pulsar orbiting a black hole and, by watching how the clock rate varies, we can tell if Einstein had the last word on gravity or not”, he says.

Prof Richard Schilizzi, the International SKA Project Director, stresses the scale of the instrument needed to fulfil these science goals. “Designing and then building, such an enormous technologically-advanced instrument is beyond the scope of individual nations. Only by harnessing the ideas and resources of countries around the world is such a project possible”. Astronomers in Australia, South Africa, Canada, India, China and the USA are collaborating closely with colleagues in Europe to develop the required technology which will include sophisticated electronics and powerful computers that will play a far bigger role than in the present generation of radio telescopes. The European effort is based on phased array receivers, similar to those in aircraft radar systems. When placed at the focus of conventional mass-produced radio ‘dishes’, these arrays operate like wide-angle radio cameras enabling huge areas of sky to be observed simultaneously. A separate, much larger, phased array at the centre of the SKA will act like a radio fish-eye lens, constantly scanning the sky.

Funding for this global design programme has been provided by the European Commission’s Framework 6 ‘Design Studies’ programme, which is contributing about 27% of the total ?38M funding over the next four years. Individual countries are contributing the remainder. The UK has invested ?5.6M (?8.3M) funding provided by PPARC.
When coupled with the UK’s share of the EC contribution, then the UK’s overall contribution to the SKA Design Study (SKADS) programme is about 30% of the total.

The ?38M European technology development programme is funded by the European Commission and governments in eight countries led by the Netherlands, the UK, France and Italy. The programme is being coordinated by Ir. Arnold van Ardenne, Head of Emerging Technologies at The Netherlands ASTRON Institute. In van Ardenne’s view “the critical task is to demonstrate that large numbers of electronic arrays can be built cost effectively – so that our dreams of radio cameras and radio fish-eye lenses can be turned into reality”.

In the UK, a group of universities currently including Manchester, Oxford, Cambridge, Leeds and Glasgow, funded by PPARC, is involved in all aspects of the design but is concentrating on sophisticated digital phased arrays and the distribution and analysis of the enormous volumes of data which the SKA will produce. University of Cambridge’s Dr Paul Alexander makes the point that “the electronics in the SKA makes it very flexible and allows for completely new ways of scanning the sky. But to make it work will require massive computing power”. Designers believe that by the time the SKA reaches full operation, 14 years from now, a new generation of computers will be up to the task.

The geographical location of SKA will be decided in the mid-term future and several nations have already expressed interest in hosting this state of the art astronomical facility.

Original Source: PPARC News Release

Posted on by Fraser Cain

New Horizons Blasts Off for Pluto

Liftoff of the Atlas V carrying NASA’s New Horizons spacecraft. Image credit: NASA/KSC Click to enlarge
The first mission to distant planet Pluto is under way after the successful launch today of NASA’s New Horizons spacecraft from Cape Canaveral Air Force Station, Fla.

New Horizons roared into the afternoon sky aboard a powerful Atlas V rocket at 2 p.m. EST. It separated from its solid-fuel kick motor 44 minutes, 53 seconds after launch, and mission controllers at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., where the spacecraft was designed and built, received the first radio signals from New Horizons a little more than five minutes later. The radio communications, sent through NASA’s Deep Space Network antennas in Canberra, Australia, confirmed to controllers that the spacecraft was healthy and ready to begin initial operations.

“Today, NASA began an unprecedented journey of exploration to the ninth planet in the solar system,” says Dr. Colleen Hartman, deputy associate administrator for NASA’s Science Mission Directorate, Washington, D.C. “Right now, what we know about Pluto could be written on the back of a postage stamp. After this mission, we’ll be able to fill textbooks with new information.”

The 1,054-pound, piano-sized spacecraft is the fastest ever launched, speeding away from Earth at approximately 36,000 miles per hour, on a trajectory that will take it more than 3 billion miles toward its primary science target. New Horizons will zip past Jupiter for a gravity assist and science studies in February 2007, and conduct the first close-up, in-depth study of Pluto and its moons in summer 2015. As part of a potential extended mission, the spacecraft would then examine one or more additional objects in the Kuiper Belt, the region of ancient, icy, rocky bodies (including Pluto) far beyond Neptune?s orbit.

“The United States of America has just made history by launching the first spacecraft to explore Pluto and the Kuiper Belt beyond,” says Dr. Alan Stern, New Horizons principal investigator, from Southwest Research Institute in Boulder, Colo. No other nation has this capability. This is the kind of exploration that forefathers like Lewis and Clark, 200 years ago this year, made a trademark of our nation.”

Over the next several weeks, mission operators at APL will place the spacecraft in flight mode, check out its critical operating systems and perform small propulsive maneuvers to refine its path toward Jupiter. Following that, among other operations, the team will begin checking and commissioning most of the seven science instruments.

“This is the gateway to a long, exciting journey,” says Glen Fountain, New Horizons project manager from APL. “The team has worked hard for the past four years to get the spacecraft ready for the voyage to Pluto and beyond, to places we’ve never seen up close. This is a once-in-a-lifetime opportunity, in the tradition of the Mariner, Pioneer, and Voyager missions to set out for first looks in our solar system.”

After the Jupiter encounter ? during which New Horizons will train its science instruments on the large planet and its moons ?? the spacecraft will “sleep” in electronic hibernation for much of the cruise to Pluto. Operators will turn off all but the most critical electronic systems and check in with the spacecraft once a year to check out the critical systems, calibrate the instruments and perform course corrections, if necessary.

Between the in-depth checkouts, New Horizons will send back a beacon signal each week to give operators an instant read on spacecraft health. The entire spacecraft, drawing electricity from a single radioisotope thermoelectric generator, operates on less power than a pair of 100-watt household light bulbs.

New Horizons is the first mission in NASA’s New Frontiers Program of medium-class spacecraft exploration projects. Stern leads the mission and science team as principal investigator. APL manages the mission for NASA’s Science Mission Directorate and is operating the spacecraft in flight. The mission team also includes Ball Aerospace Corporation, the Boeing Company, NASA Goddard Space Flight Center, NASA Jet Propulsion Laboratory, Stanford University, KinetX, Inc., Lockheed Martin Corporation, University of Colorado, the U.S. Department of Energy, and a number of other firms, NASA centers, and university partners.

Original Source: APL News Release

Posted on by Fraser Cain

Self-Repairing Spacecraft

A time lapse sequence of self-repair taking place. Image credit: ESA Click to enlarge
Building spacecraft is a tough job. They are precision pieces of engineering that have to survive in the airless environment of space, where temperatures can swing from hundreds of degrees Celsius to hundreds of degree below zero in moments. Once a spacecraft is in orbit, engineers have virtually no chance of repairing anything that breaks. But what if a spacecraft could fix itself?

Thanks to a new study funded by ESA’s General Studies Programme, and carried out by the Department of Aerospace Engineering, University of Bristol, UK, engineers have taken a step towards that amazing possibility. They took their inspiration from nature.

“When we cut ourselves we don’t have to glue ourselves back together, instead we have a self-healing mechanism. Our blood hardens to form a protective seal for new skin to form underneath,” says Dr Christopher Semprimoschnig, a materials scientist at ESA’s European Space Technology Research Centre (ESTEC) in the Netherlands, who oversaw the study.

He imagined such cuts as analogous to the ‘wear-and-tear’ suffered by spacecraft. Extremes of temperature can cause small cracks to open in the superstructure, as can impacts by micrometeroids – small dust grains travelling at remarkable speeds of several kilometres per second. Over the lifetime of a mission the cracks build up, weakening the spacecraft until a catastrophic failure becomes inevitable.

The challenge for Semprimoschnig was to replicate the human process of healing small cracks before they can open up into anything more serious. He and the team at Bristol did it by replacing a few percent of the fibres running through a resinous composite material, similar to that used to make spacecraft components, with hollow fibres containing adhesive materials. Ironically, to make the material self-repairable, the hollow fibres had to be made of an easily breakable substance: glass. “When damage occurs, the fibres must break easily otherwise they cannot release the liquids to fill the cracks and perform the repair,” says Semprimoschnig.

In humans, the air chemically reacts with the blood, hardening it. In the airless environment of space, alternate mechanical veins have to be filled with liquid resin and a special hardener that leak out and mix when the fibres are broken. Both must be runny enough to fill the cracks quickly and harden before it evaporates.

“We have taken the first step but there is at least a decade to go before this technology finds its way onto a spacecraft,” says Semprimoschnig, who believes that larger scale tests are now needed.

The promise of self-healing spacecraft opens up the possibility of longer duration missions. The benefits are two-fold. Firstly, doubling the lifetime of a spacecraft in orbit around Earth would roughly halve the cost of the mission. Secondly, doubling spacecraft lifetimes means that mission planners could contemplate missions to far-away destinations in the Solar System that are currently too risky.

In short, self-healing spacecraft promise a new era of more reliable spacecraft, meaning more data for scientists and more reliable telecommunication possibilities for us all.

Original Source: ESA Portal

Posted on by Fraser Cain

Saturnian Storms About to Merge

Saturnian storms swirling in the region “storm alley”. Image credit: NASA/JPL/SSI Click to enlarge
Two Saturnian storms swirl in the region informally dubbed “storm alley” by scientists. This mid-latitude region has been active with storms since Cassini scientists began monitoring Saturn in early 2004.

The large storm at left is at least 2,500 kilometers (1,600 miles) across from north to south. This is bigger than typical storms in the region, which are the size of large Earth hurricanes, or about 1,000 kilometers (600 miles) across. To the left, the smaller storm is about 700 kilometers (400 miles) across.

The two storms are interacting. Their threadlike arms are intertwined, and they might have merged a few days after this image was taken. See PIA06082 and PIA06083 for movies of storm activity in this region.

The image was taken with the Cassini spacecraft narrow-angle camera on Dec. 9, 2005, at a distance of approximately 3.2 million kilometers (2 million miles) from Saturn. The image was obtained using a filter sensitive to wavelengths of infrared light centered at 727 nanometers. The image scale is 38 kilometers (23 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Posted on by Nancy Atkinson

Satellites on a Budget – High Altitude Balloons

Balloon photograph taken from 25km. Image credit: Paul Verhage. Click to enlarge.
Paul Verhage has some pictures that you’d swear were taken from space. And they were. But Verhage is not an astronaut, nor does he work for NASA or any company that has satellites orbiting Earth. He is a teacher in the Boise, Idaho school district. His hobby, however, is out of this world.

Verhage is one of about 200 people across the United States who launch and recover what have been called a “poor man’s satellite.” Amateur Radio High Altitude Ballooning (ARHAB) allows individuals to launch functioning satellites to “near space,” at a fraction of the cost of traditional rocket launch vehicles.

Usually, the cost to launch anything into space on regular rockets is quite high, reaching thousands of dollars per pound. Additionally, the waiting period for payloads to be put on a manifest and then launched can be several years.

Verhage says that the total cost for building, launching and recovering these Near Spacecraft is less than $1,000. “Our launch vehicles and fuel are latex weather balloons and helium,” he said.

Plus, once an individual or small group begins designing a Near Spacecraft, it could be ready for launch within six to twelve months.

Verhage has launched about 50 balloons since 1996. Payloads on his Near Spacecraft include mini-weather stations, Geiger counters and cameras.

Near space lies begins between 60,000 and 75,000 feet (~ 18 to 23 km) and continues to 62.5 miles (100km), where space begins.

“At these altitudes, air pressure is only 1% of that at ground level, and air temperatures are approximately -60 degrees F,” he said. “These conditions are closer to the surface of Mars than to the surface of Earth.”

Verhage also said that because of the low air pressure, the air is too thin to refract or scatter sunlight. Therefore, the sky is black rather than blue. So, what is seen at these altitudes is very close to what the shuttle astronauts see from orbit.

Verhage said his highest flight reached an altitude of 114,600 feet (35 km), and his lowest went only 8 feet (2.4 meters) off the ground.

The main parts of a Near Spacecraft are flight computers, an airframe, and a recovery system. All these components are reusable for multiple flights. “Think of building this Near Spacecraft as building your own reusable Space Shuttle,” said Verhage.

The avionics operates experiments, collects data, and determines the status of the spacecraft, and Verhage makes his own flight computers. The airframe is usually the most inexpensive part of the spacecraft and can be made from materials such as Styrofoam and Ripstop Nylon, put together with hot glue.

The recovery system consists of a GPS, a radio receiver such as a ham radio, and a laptop with GPS software. Additionally, and probably most important is the Chase Crew. “It’s like a road rally,” says Verhage, “but no one in the Chase Crew knows quite for sure where they are going to end up!”

The process of launching a Near Spacecraft involves getting the capsule ready, filling the balloon with helium and releasing it. Ascent rates for the balloons vary for each flight but are typically between 1000 and 1200 feet per minute, with the flights taking 2-3 hours to reach apogee. A filled balloon is about 7 feet tall and 6 feet wide. They expand in size as the balloon ascends, and at maximum altitude can be over 20 feet wide.

The flight ends when the balloon bursts from the reduced atmospheric pressure. To ensure a good landing, a parachute is pre-deployed before launch. A Near Spacecraft will free fall, with speeds of over 6,000 feet per minute until about 50,000 feet in altitude, where the air is dense enough to slow the capsule.

The GPS receiver that Verhage uses signals its position every 60 seconds, so after the spacecraft lands, Verhage and his team usually know where the spacecraft is, but recovering it is mostly a matter of being able to get to where it lies. Verhage has lost only one capsule. The batteries died during the flight, so the GPS wasn’t functioning. Another capsule was recovered 815 days after launch, found by the Air National Guard near a bombing range.

Some balloons are recovered only 10 miles from the launch site, while others have traveled over 150 miles away.

“Some of the recoveries are easy,” said Verhage. “In one flight, one of my chase crew, Dan Miller, caught the balloon as it landed. But some recoveries in Idaho are tough. We’ve spent hours climbing a mountain in some cases.”

Other experiments that Verhage has flown include a Visible Light Photometer, Medium Bandwidth Photometers, an Infrared Radiometer, a Glider Drop, Insect Survival, and Bacteria Exposure.

One of Verhage’s most interesting experiments involved using a Geiger counter to measure cosmic radiation. On the ground, a Geiger counter detects about 4 cosmic rays a minute. At 62,000 the count goes to 800 counts per minute, but Verhage discovered that above that altitude the count does down. “I learned about primary cosmic rays from that discovery,” he said.

Flying the experiments are a great experience, Verhage said, but launching a camera and getting pictures from Near Space provides an irreplaceable “wow” factor. “To have an image of the Earth showing its curvature is pretty amazing,” Verhage said.

“For cameras,” he continued, “the dumber they are the better. Too many of the newer cameras have a power save feature, so they shut off when they’re not used in so many minutes. When they turn off at 50,000 feet, there’s nothing I can do to turn them back on.”

While digital cameras are easy to interface with the flight computer, Verhage said, they require some inventive wiring too keep the camera from shutting off. He said that so far, his best photos have come from film cameras.

Verhage is writing an e-book that details how to build, launch and recover a Near Spacecraft, and the first 8 chapters are available free, online. The e-book will have 15 chapters when finished, totaling about 800 pages in length.
Parallax, the company that manufactures a microcontroller is sponsoring the e-book’s publication.

Verhage teaches electronics at the Dehryl A. Dennis Professional Technical Center in Boise. He writes a bimonthly column about his adventures with ARHAB for Nuts and Volts magazine, and also shares his enthusiasm for space exploration through the NASA/JPL Solar System Ambassador program.

Verhage said his hobby incorporates everything he is interested in: GPS, microcontrollers and space exploration, and he encourages anyone to experience the thrill of sending a spacecraft to Near Space.

By Nancy Atkinson