Posted on by Fraser Cain

Rosetta Will Launch in a Month

Image credit: ESA
Rosetta is scheduled to be launched on board an Ariane-5 rocket on 26 February from Kourou, French Guiana.

Originally timed to begin about a year ago, Rosetta’s journey had to be postponed, as a precaution, following the failure of a different version of Ariane-5 in December 2002. This will be the first mission to orbit and land on a comet, one of the icy bodies that travel throughout the Solar System and develop a characteristic tail when they approach the Sun.

This delay meant that the original mission’s target, Comet Wirtanen, could no longer be reached. Instead, a new target has been selected, Comet 67P/Churyumov-Gerasimenko, which Rosetta will encounter in 2014 after a ?billiard ball? journey through the Solar System lasting more than ten years. Rosetta?s name comes from the famous ?Rosetta Stone?, from which Egyptian hieroglyphics were deciphered almost 200 years ago. In a similar way, scientists hope that the Rosetta spacecraft will unlock the mysteries of the Solar System.

Comets are very interesting objects for scientists, since their composition reflects how the Solar System was when it was very young and still ‘unfinished’, more than 4600 million years ago. Comets have not changed much since then. In orbiting Comet Churyumov-Gerasimenko and landing on it, Rosetta will collect information essential to an understanding of the origin and evolution of our Solar System. It will also help discover whether comets contributed to the beginnings of life on Earth. In fact comets are carriers of complex organic molecules that, delivered to Earth through impacts, perhaps played a role in the origin of living forms. Furthermore, ?volatile? light elements carried by comets might also have played an important role in forming the Earth?s oceans and atmosphere.

?Rosetta is one of the most challenging missions undertaken so far,? says Professor David Southwood, ESA Director of Science. ?No one has ever attempted such a mission, unique for its scientific implications as well as for its complex and spectacular interplanetary space manoeuvres.? Before reaching its target in 2014, Rosetta will circle the Sun four times on wide loops in the inner Solar System. During its long trek, the spacecraft will have to endure some extreme thermal conditions. Once it is close to Comet Churyumov-Gerasimenko, scientists will take it through a delicate braking manoeuvre; the spacecraft will then closely orbit the comet, and gently drop a lander on it. It will be landing on a small, fast-moving ?cosmic bullet? about whose ‘geography’ very little is known yet.

An amazing 10-year interplanetary trek
Rosetta is a three-tonne box-type spacecraft about three metres high, with two 14-metre solar panels. It consists of an orbiter and a lander. The lander is approximately one metre across and 80 centimetres high. It will be attached to the side of the orbiter during the journey to Comet Churyumov-Gerasimenko. Rosetta carries 21 experiments in total, 10 of them on the lander. They will be kept in hibernation during most of its 10-year trek towards the comet.

Why does Rosetta’s cruise need to take so long? To reach Comet Churyumov-Gerasimenko, the spacecraft needs to go out into deep space as far out from the Sun as Jupiter. No launcher could possibly get Rosetta there directly. ESA’s spacecraft will gather speed from gravitational ?kicks? provided by four planetary fly-bys: one of Mars in 2007 and three of Earth in 2005, 2007 and 2009. During the trip, Rosetta will also twice pass through the asteroid belt, where a fly-by with one or more of these primitive objects is possible. A number of candidate targets have already been identified, but the final selection will be made after launch, once the amount of surplus fuel has been verified by mission engineers. During these encounters, scientists plan to switch on Rosetta’s instruments for scientific studies of these largely unexplored Solar System bodies.

Long trips in deep space include many hazards, such as extreme changes in temperature. Rosetta will leave the benign environment of near-Earth space to the dark, frigid regions beyond the asteroid belt. To manage these thermal loads, experts have done very tough pre-launch tests to study Rosetta’s endurance. For example, they have heated its external surfaces to more than 150?C, then cooled it to -150?C in the next test.

The spacecraft will be fully reactivated prior to the comet rendezvous manoeuvre in 2014. Then, Rosetta will orbit the comet ? an object only about 4 kilometres in diameter – while it cruises through the inner Solar System at 135 000 kilometres per hour. At the time of the rendezvous ? around 675 million kilometres from the Sun ? Comet Churyumov-Gerasimenko will hardly show any surface activity. This means that the characteristic ?coma? (the comet?s ?atmosphere?) and the tail will not be formed yet, because of the distance from the Sun. The comet’s tail is in fact made of dust grains and frozen gases from the comet’s surface that vaporise because of the Sun’s heat.

Over a period of six months, Rosetta will extensively map the comet’s surface, prior to selecting a landing site. In November 2014, the lander will be ejected from the spacecraft from a height which could be as low as one kilometre. Touchdown will be at walking speed, about one metre per second. Immediately after touchdown, the lander will fire a harpoon into the ground to avoid bouncing off the surface back into space, since the comet?s extremely weak gravity alone would not hold onto the lander. Operations and scientific observations on the surface will last at least a week, but may continue for many months. Besides taking close-up pictures, the lander will drill into the dark organic crust and sample the primordial ices and gases.

During and after the lander operations, Rosetta will continue orbiting and studying the comet: it will be the first spacecraft to witness at close quarters the changes taking place in a comet when the comet approaches the Sun and grows its coma and tail and then travels away from it. The trip will end in December 2015, after 12 years of adventure, when the comet has made its closest approach to the Sun and is on its way towards the outer Solar System.

Studying a comet on the spot
Rosetta’s goal is to examine the comet in great detail. The instruments on the orbiter include several cameras and spectrometers that work at different wavelengths: infrared, ultraviolet, visible and microwave. In addition, there are various other instruments to make in situ analysis. Together, they will provide, amongst other things, very high-resolution images and information about the shape, density, temperature and chemical composition of the comet. Rosetta?s instruments will analyse the gases and dust grains in the coma that forms when the comet becomes active, as well as the interaction with the solar wind.

The ten experiments on the lander will make an on-the-spot analysis of the composition and structure of the comet?s surface and subsurface material. A drilling system will take samples down to 30 centimetres below the surface and feed these to the ?composition analysers?. Other instruments will measure properties such as near-surface strength, density, texture, porosity, ice phases and thermal properties. Microscopic studies of individual grains will tell us about the texture.

Ground operations
All scientific data including those relayed from the lander will be stored on the orbiter for downlink to Earth at the next ground station contact. ESA has installed a new deep-space antenna at New Norcia, near Perth in Western Australia, as the main communications link between the spacecraft and ESOC Mission Control in Darmstadt, Germany. This 35-metre diameter parabolic antenna allows the radio signal to reach distances of more than a million kilometres from Earth. The radio signals, travelling at the speed of light, will take up to 50 minutes to cover the distance between the spacecraft and Earth.

Building Rosetta
Rosetta was selected as a mission in 1993. The spacecraft has been built by Astrium Germany as prime contractor. Major subcontractors are Astrium UK (spacecraft platform), Astrium France (spacecraft avionics), and Alenia Spazio (assembly, integration, and verification). Rosetta?s industrial team involves more than 50 contractors from 14 European countries, Canada and the United States.

Scientific consortia from institutes across Europe and the United States have provided the instruments on the orbiter. A European consortium under the leadership of the German Aerospace Research Institute (DLR) has provided the lander. Rosetta has cost ESA EUR 770 million at 2000 economic conditions. This includes the launch and the entire period of development and mission operations from 1996 to 2015. The lander and the experiments, the so-called ‘payload’, are not included since they are funded by the member states through scientific institutes.

Original Source: ESA News Release

Posted on by Fraser Cain

Astronomers See a Star Before it Exploded

Image credit: Gemini
Like a doctor trying to understand an elderly patient’s sudden demise, astronomers have obtained the most detailed observations ever of an old but otherwise normal massive star just before and after its life ended in a spectacular supernova explosion.

Imaged by the Gemini Observatory and Hubble Space Telescope (HST) less than a year prior to the gigantic explosion, the star is located in the nearby galaxy M-74 in the constellation of Pisces. These observations allowed a team of European astronomers led by Dr. Stephen Smartt of the University of Cambridge, England to verify theoretical models showing how a star like this can meet such a violent fate.

The results were published in the January 23, 2004 issue of the journal Science. This work provides the first confirmation of the long-held theory that some of the most massive (yet normal) old stars in the Universe end their lives in violent supernova explosions.

“It might be argued that a certain amount of luck or serendipity was involved in this finding,” said Dr. Smartt. “However, we’ve been searching for this sort of normal progenitor star on its deathbed for some time. I like to think that finding the superb Gemini and HST data for this star is a vindication of our prediction that one day we had to find one of these stars in the immense data archives that now exist.” Click here for more details on Dr. Smartt’s ongoing supernova program.

During the last few years, Smartt’s research team has been using the most powerful telescopes, both in space and on the ground, to image hundreds of galaxies in the hope that one of the millions of stars in these galaxies will some day explode as a supernova. In this case, the renowned Australian amateur supernova hunter, Reverend Robert Evans, made the initial discovery of the explosion (identified as SN203gd) while scanning galaxies with a 12-inch (31cm) backyard telescope from his home in New South Wales, Australia in June, 2003.

Following Evans’ discovery, Dr. Smartt’s team quickly followed up with detailed observations using the Hubble Space Telescope. These observations verified the exact position of the original or “progenitor” star. Using this positional data, Smartt and his team dug through data archives and discovered that observations by the Gemini Observatory and HST contained the combination of data necessary to reveal the nature of the progenitor.

The Gemini data was obtained during the commissioning of the Gemini Multi-Object Spectrograph (GMOS) on Mauna Kea, Hawaii in 2001. These data were also used to produce a stunning high-resolution image of the galaxy that clearly shows the red progenitor star. Click here for the full resolution Gemini image.

Armed with the earlier Gemini and HST observations Smartt’s team was able to demonstrate that the progenitor star was what astronomers classify as a normal red supergiant. Prior to exploding, this star appeared to have a mass about 10 times greater, and a diameter about 500 times greater than that of our Sun. If our sun were the size of the progenitor it would engulf the entire inner solar system out to about the planet Mars.

Red supergiant stars are quite common in the universe and an excellent example can be easily spotted during January from almost anywhere on the Earth by looking at Betelgeuse, the bright red shoulder star in the constellation of Orion (see finder chart here.) Like SN2003gd, it is believed that Betelgeuse could meet the same explosive fate at any time from next week to thousands of years from now.

After SN2003gd exploded, the team observed its gradually fading light for several months using the Isaac Newton Group of telescopes on La Palma. These observations demonstrated that this was a normal type II supernova, which means that the ejected material from the explosion is rich in hydrogen. Computer models developed by astronomers have long predicted that red supergiants with extended, thick atmospheres of hydrogen would produce these type II supernovae but until now have not had the observational evidence to back up their theories. However, the fantastic resolution and depth of the Gemini and Hubble images allowed the Smartt team to estimate the temperature, luminosity, radius and mass of this progenitor star and reveal that it was a normal large, old star. “The bottom-line is that these observations provide a strong confirmation that the theories for both stellar evolution and the origins of these cosmic explosions are correct,” said co-author Seppo Mattila of Stockholm Observatory.

This is only the third time astronomers have actually seen the progenitor of a confirmed supernova explosion. The others were peculiar type II supernovae: SN 1987A, which had a blue supergiant progenitor, and SN 1993J, which emerged from a massive interacting binary star system. Click here for more details.

Dr. Smartt concludes, “Supernova explosions produce and distribute the chemical elements that make up everything in the visible Universe ? especially life. It is critical that we know what type of stars produce these building blocks if we are to understand our origins.”

Archived Gemini and HST data was critical to the success of this project. “This discovery is a perfect example of archival data’s immense value to new scientific projects,” said Dr. Colin Aspin who is the Gemini Scientist responsible for the development of the Gemini Science Archive (GSA). He continued, “this discovery demonstrates the spectacular results that can be realized by using archival data and stresses the importance of developing the GSA for future generations of astronomers.”

The Gemini Multi-Object Spectrograph used to make the Gemini observations are twin instruments built as a joint partnership between Gemini, the Dominion Astrophysical Observatory, Canada, the UK Astronomy Technology Centre and Durham University, UK. Separately, the U.S. National Optical Astronomy Observatory provided the detector subsystem and related software. GMOS is primarily designed for spectroscopic studies where several hundred simultaneous spectra are required, such as when observing star and galaxy clusters. GMOS also has the ability to focus astronomical images on its array of over 28 million pixels.

The Isaac Newton Group of Telescopes (ING) is an establishment of the Particle Physics and Astronomy Research Council (PPARC) of the United Kingdom, the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) of the Netherlands and the Instituto de Astrof?sica de Canarias (IAC) in Spain. The ING operates the 4.2 metre William Herschel Telescope, the 2.5 metre Isaac Newton Telescope, and the 1.0 metre Jacobus Kapteyn Telescope. The telescopes are located in the Spanish Roque de Los Muchachos Observatory on La Palma which is operated by the Instituto de Astrof?sica de Canarias (IAC).

Background Information:

Supernovae are among the most energetic phenomena observed in the entire Universe. When a star of more than about eight times the mass of our Sun reaches the end of its nuclear fuel reserve, its core is no longer stable from collapsing under its own immense weight. As the core of the star collapses, the outer layers are ejected in a fast-moving shock wave. This huge energy release results in a supernova that is about one billion times brighter than our Sun, and is comparable to the brightness of an entire galaxy. After destroying itself, the core of the star becomes either a neutron star or a black hole.

The team is composed of Stephen J. Smartt, Justyn R. Maund, Margaret A. Hendry, Christopher A. Tout, and Gerald F. Gilmore (University of Cambridge, UK), Seppo Mattila (Stockholm Observatory, Sweden), and Chris R. Benn (Isaac Newton Group of Telescopes, Spain).

Original Source: Gemini News Release

Posted on by Fraser Cain

Halo Around a Gamma Ray Burst

Image credit: PPARC
The discovery of a unique phenomenon: a beautiful set of expanding X-ray halos surrounding a gamma-ray burst which have never been seen before, (see Movie link at end), has been announced by an international team of astronomers led by Dr Simon Vaughan of the University of Leicester. The research has been accepted for publication in the Astrophysical Journal.

Gamma-ray bursts (GRB) are the most energetic form of radiation in the Universe and can be used to probe any material between Earth and the burst. In this case, the GRB lies behind the plane of our Galaxy, so its light has to travel through the gas and dust in the Galactic disc to reach us.

ESA’s gamma ray observatory satellite ‘Integral’ detected the 30 second long GRB 031203 on December 3rd 2003 and the halos were discovered in a follow-up observation that started 6 hours after the burst with ESA’s ‘XMM-Newton’ X-ray space telescope.

Commenting on the discovery, Professor Ian Halliday, Chief Executive of the UKs Particle Physics and Astronomy Research Council (PPARC) said Gamma-ray bursts are the most violent events in the Universe. Unlike the serene beauty of the stars that we can see with our eyes, the Gamma Ray Universe is a place of dramatic explosions, cosmic collisions and matter being sucked into black holes.

Halliday added This is a wonderful example of two of ESAs most advanced observatories in which UK scientists have made a significant contribution, working in harmony to reveal a new level of scientific understanding.

The fading X-ray emission from the GRB – the afterglow – is clearly seen in the image from the X-ray cameras on XMM-Newton. Uniquely, two rings centred on the afterglow were also seen. Dr Vaughan said “These rings are due to dust in our own Galaxy which is illuminated by the X-rays from the gamma-ray burst. The dust scatters some of the X-rays causing the rings, in the same way as fog scatters the light from a car’s headlights.” He added “Its like a shout in a cathedral; the shout of the gamma-ray burst is louder, but the Galactic reverberation, seen as the rings, is more beautiful.”

Due to the finite speed of light, X-rays from more distant dust reach us later, giving rise to the appearance of expanding rings. Dr Vaughan said “We expect to see an expanding ring on the sky if the dust is in a sheet roughly in the plane of the sky, but as we see two rings there must be two dust sheets between us and the GRB. Understanding how dust is distributed in our Galaxy is important. Dust helps cool gas clouds which can then collapse to form stars and planets. Knowing where dust is located helps astronomers determine where star and planet formation is likely to occur.”

Expanding X-ray dust scattering rings have never been seen before. Slower moving rings seen in visible light around a very few supernovae are caused by a similar effect.

The two halos are due to thin sheets of dust at 2,900 and 4,500 light-years away; the astronomers accurately measured the distances from the expansion rate of the halos. The distances have an uncertainty of just 2%, a remarkable level of accuracy for an object in our Galaxy. The nearest dust sheet is probably part of the Gum nebula, a bubble of hot gas resulting from many supernova explosions. The GRB itself is thought to have occurred in a small galaxy about a billion light-years away (one of the closest GRB galaxies).

Astronomers are still trying to understand the mysterious gamma-ray bursts. Some occur with the supernova explosion of a massive star when it has used up all of its fuel, although only stars which have lost their outer layers and which collapse to make a black hole seem able to make a GRB.

Today Integral and XMM-Newton provide astronomers with their most powerful facilities for studying gamma-ray bursts, but 2004 will see the launch of “Swift”, a new NASA mission with major UK involvement, which will be dedicated to GRBs. This will work in concert with the two ESA satellite observatories, providing more opportunities for discoveries in this cutting edge field. UK participation in Integral, XMM-Newton and Swift is funded by the Particle Physics and Astronomy Research Council.

Original Source: PPARC

Posted on by Fraser Cain

Search for Beagle 2 is Winding Down

Image credit: Beagle 2
No contact has been made with the Beagle 2 lander, despite repeated efforts over the last few days to communicate via the Mars Express and Mars Odyssey spacecraft and the Jodrell Bank radio telescope in Cheshire, UK.

At a press briefing in London this afternoon, members of the Beagle 2 team described the latest efforts to contact their missing lander.

“We haven?t found Beagle 2, despite three days of intensive searching,” said Professor Colin Pillinger, lead scientist for Beagle 2. “Under those circumstances, we have to begin to accept that, if Beagle 2 is on the Martian surface, it is not active.

“That isn?t to say that we are going to give up on Beagle. There is one more thing that we can do – however, it is very much a last resort. We will be asking the American Odyssey spacecraft (team) tomorrow whether they will send an embedded command – a hail to Beagle with a command inside it. If it gets through, it will tell Beagle to switch off and reload the software. We are now working on the basis that there is a corrupt system and the only way we might resurrect is to send that command.”

“We can also ask Mars Express to send that command. However, they cannot send it probably until the 2 or 3 February,” he added.

“We?ll move with the next phase in the search for Beagle 2,” said Professor Pillinger. “We have discussed on our side of the house what we intend to do in the future. We are dedicated to trying to refly Beagle 2 in some shape or form, therefore we need to know how far it got because we need know which parts of this mission we don?t have to study in further detail.”

Detailing the efforts to contact Beagle 2 in recent days, Mark Sims, Beagle 2 Mission Manager from the University of Leicester, explained that the lander should have entered an emergency communication mode known as CSM2 no later than 22 January. In this mode, the spacecraft?s receiver is switched on throughout daylight hours on Mars. The only possible explanation that no communication has been established during the last few days is that the lander?s battery is in a low state of charge.

Meanwhile, the academia-industry “Tiger Team” at the National Space Centre in Leicester is beginning to concentrate on detailed analysis of the possible causes for failure of the mission and the lessons that can be learned for future missions.

The analysis of the mission now under way includes an assessment of the landing site ellipse from orbital images, reanalysis of atmospheric conditions during the entry into the Martian atmosphere on 25 December, examination of the separation from Mars Express and of the cruise phase preceding arrival at Mars.

One extremely useful piece of evidence could be provided by an image of the lander. The team is hoping that the High Resolution Stereo Camera on Mars Express or the camera on board Mars Global Surveyor may eventually be able to capture an image that reveals its location on the Martian surface.

Original Source: PPARC News Release

Posted on by Fraser Cain

Opportunity is in a Small Crater

Image credit: NASA/JPL
A small impact crater on Mars is the new home for NASA’s Opportunity rover, and a larger crater lies nearby. Scientists value such crater locations as a way to see what’s beneath the surface without needing to dig.

Encouraging developments continued for Opportunity’s twin, Spirit, too. Engineers have determined that Spirit’s flash memory hardware is functional, strengthening a theory that Spirit’s main problem is in software that controls file management of the memory. “I think we’ve got a patient that’s well on the way to recovery,” said Mars Exploration Rover Project Manager Pete Theisinger at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Opportunity returned the first pictures of its landing site early today, about four hours after reaching Mars. The pictures indicate that the spacecraft sits in a shallow crater about 20 meters (66 feet) across.

“We have scored a 300-million mile interplanetary hole in one,” said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science instruments on both rovers.

NASA selected Opportunity’s general landing area within a region called Meridiani Planum because of extensive deposits of a mineral called crystalline hematite, which usually forms in the presence of liquid water. Scientists had hoped for a specific landing site where they could examine both the surface layer that’s rich in hematite and an underlying geological feature of light-colored layered rock. The small crater appears to have exposures of both, with soil that could be the hematite unit and an exposed outcropping of the lighter rock layer.

“If it got any better, I couldn’t stand it,” said Dr. Doug Ming, rover science team member from NASA Johnson Space Center, Houston. With the instruments on the rover and just the rocks and soil within the small crater, Opportunity should be allow scientists to determine which of several theories about the region’s past environment is right, he said. Those theories include that the hematite may have formed in a long-lasting lake or in a volcanic environment.

An even bigger crater, which could provide access to deeper layers for more clues to the past, lies nearby. Images taken by a camera on the bottom of the lander during Opportunity’s final descent show a crater about 150 meters (about 500 feet) across likely to be within about one kilometer or half mile of the landing site, said Dr. Andrew Johnson of JPL. He is an engineer for the descent imaging system that calculated the spacecraft’s horizontal motion during its final seconds of flight. The system determined that sideways motion was small, so Opportunity’s computer decided not to fire the lateral rockets carried specifically for slowing that motion.

Squyres presented an outline for Opportunity’s potential activities in coming weeks and months. After driving off the lander, the rover will first examine the soil right next to the lander, then drive to the outcrop of layered-looking rocks and spend considerable time examining it. Then the rover may climb out of the small crater, take a look around, and head for the bigger crater.

But first, Opportunity will spend more than a week — perhaps two — getting ready to drive off the lander, if all goes well. Engineering data from Opportunity returned in relays via NASA’s Mars Odyssey orbiter early this morning and at midday indicate the spacecraft is in excellent health, said JPL’s Arthur Amador, mission manager. The rover will try its first direct-to-Earth communications this evening.

The main task for both rovers in coming months is to explore the areas around their landing sites for evidence in rocks and soils about whether those areas ever had environments that were watery and possibly suitable for sustaining life.

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Additional information about the project is available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Engineers Restore Communications With Spirit

Image credit: NASA/JPL
Hours before NASA’s Opportunity rover will reach Mars, engineers have found a way to communicate reliably with its twin, Spirit, and to get Spirit’s computer out of a cycle of rebooting many times a day.

Spirit’s responses to commands sent this morning confirm a theory developed overnight that the problem is related to the rover’s two “flash” memories or software controlling those memories.

“The rover has been upgraded from critical to serious,” said Mars Exploration Rover Project Manager Peter Theisinger at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Significant work is still ahead for restoring Spirit, he predicted.

Opportunity is on course for landing in the Meridiani Planum region of Mars. The center of an ellipse covering the area where the spacecraft has a 99 percent chance of landing is just 11 kilometers (7 miles) from the target point. That point was selected months ago. Mission managers chose not to use an option for making a final adjustment to the flight path. Previously, the third and fifth out of five scheduled maneuvers were skipped as unnecessary. ” We managed to target Opportunity to the desired atmospheric entry point, which will bring us to the target landing site, in only three maneuvers,” said JPL’s Dr. Louis D’Amario, navigation team chief for the rovers.

Opportunity will reach Mars at 05:05 Sunday, Universal Time (12:05 a.m. Sunday EST or 9:05 p.m. Saturday PST).

From the time Opportunity hits the top of Mars? atmosphere at about 5.4 kilometers per second (12,000 miles per hour) to the time it hits the surface 6 minutes later, then bounces, the rover will be going through the riskiest part of its mission. Based on analysis of Spirit’s descent and on weather reports about the atmosphere above Meridiani Planum, mission controllers have decided to program Opportunity to open its parachute slightly earlier than Spirit did.

Mars is more than 10 percent farther from Earth than it was when Spirit landed. That means radio signals from Opportunity during its descent and after rolling to a stop have a lower chance of being detected on Earth. About four hours after the landing, news from the spacecraft may arrive by relay from NASA’s Mars Odyssey orbiter. However, that will depend on Opportunity finishing critical activities, such as opening the lander petals and unfolding the rover’s solar panels, before Odyssey flies overhead.

Spirit has 256 megabytes of flash memory, a type commonly used on gear such as digital cameras for holding data even when the power is off. Engineers confirmed this morning that Spirit’s recent symptoms are related to the flash memory when they commanded the rover to boot up and utilize its random-access memory instead of flash memory. The rover then obeyed commands about communicating and going into sleep mode. Spirit communicated successfully at 120 bits per second for nearly an hour.

“We have a vehicle that is stable in power and thermal, and we have a working hypothesis we have confirmed,” Theisinger said. By commanding Spirit each morning into a mode that avoids using flash memory, engineers plan to get it to communicate at a higher data rate, to diagnose the root cause of the problem and develop ways to restore as much functioning as possible.

The work on restoring Spirit is not expected to slow the steps in getting Opportunity ready to roll off its lander platform if Opportunity lands safely. For Spirit, those steps took 12 days.

The rovers’ main task is to explore their landing sites for evidence in the rocks and soil about whether the sites’ past environments were ever watery and possibly suitable for sustaining life.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Opportunity Joins Spirit on Mars

Image credit: NASA/JPL

NASA’s Opportunity rover successfully landed on the surface of Mars early Sunday morning, giving the agency two successful landings this month. The spacecraft landed in a region of Mars called Meridiani Planum which is on the opposite side of the planet from Gusev Crater. Initial estimates placed the rover about 24 km down range from the centre of the target area, but well within the regions of hematite which could be an indication of past water. Unlike Spirit, Opportunity landed on its side and righted itself when it opened the petals of its lander. Opportunity’s airbags aren’t blocking the exit ramp, so there won’t be a problem when the rover rolls out onto the Martian surface.

NASA’s second Mars Exploration Rover successfully sent signals to Earth during its bouncy landing and after it came to rest on one of the three side petals of its four-sided lander.

Mission engineers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., received the first signal from Opportunity on the ground at 9:05 p.m. Pacific Standard Time Saturday via the NASA Deep Space Network, which was listening with antennas in California and Australia.

“We’re on Mars, everybody!” JPL’s Rob Manning, manager for development of the landing system, announced to the cheering flight team.

NASA Administrator Sean O’Keefe said at a subsequent press briefing, “This was a tremendous testament to how NASA, when really focused on an objective, can put every ounce of effort, energy, emotion and talent to an important task. This team is the best in the world, no doubt about it.”

Opportunity landed in a region called Meridiani Planum, halfway around the planet from the Gusev Crater site where its twin rover, Spirit, landed three weeks ago. Earlier today, mission managers reported progress in understanding and dealing with communications and computer problems on Spirit.

“In the last 48 hours, we’ve been on a roller coaster,” said Dr. Ed Weiler, NASA associate administrator for space science. “We resurrected one rover and saw the birth of another.”

JPL’s Pete Theisinger, project manager for the rovers, said, “We are two for two. Here we are tonight with Spirit on a path to recovery and with Opportunity on Mars.”

By initial estimates, Opportunity landed about 24 kilometers (15 miles) down range from the center of the target landing area. That is well within an outcropping of a mineral called gray hematite, which usually forms in the presence of water. “We’re going to have a good place to do science,” said JPL’s Richard Cook, deputy project manager for the rovers.

Once it pushed itself upright by opening the petals of the lander, Opportunity was expected to be facing east.

The main task for both rovers in coming months is to explore the areas around their landing sites for evidence in rocks and soils about whether those areas ever had environments that were watery and possibly suitable for sustaining life.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu .

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Engineers Struggle to Reestablish Link to Spirit

Image credit: NASA/JPL

NASA engineers have been working overtime to reestablish communications with the Spirit rover after it mysteriously stopped talking to mission control on Wednesday just before it executed an experiment to grind a few millimeters into a rock. They did receive a reassuring confirmation on Thursday that Spirit was receiving transmissions from Earth; although, it hasn’t sent any data back yet. The engineers aren’t sure what caused the problem, but since they did get that confirmation, it’s probably not in the power system, radio, transmitter or some software. A very slow communications link was established on Friday morning, but it’s still unclear exactly what’s wrong or if it’s repairable.

NASA’s Spirit rover communicated with Earth in a signal detected by NASA’s Deep Space Network antenna complex near Madrid, Spain, at 12:34 Universal Time (4:34 a.m. PST) this morning.

The transmissions came during a communication window about 90 minutes after Spirit woke up for the morning on Mars. The signal lasted for 10 minutes at a data rate of 10 bits per second.

Mission controllers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., plan to send commands to Spirit seeking additional data from the spacecraft during the subsequent few hours.

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Additional information about the project is available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Stellar Nursary in the Rosette Nebula

Image credit: NOAO

A Chinese and US astronomer have discovered a young star at the heart of the Rosette Nebula that is ejecting a complex jet of material with knots and bow shocks. Normally these stars are hidden from the view of optical telescopes by the surrounding nebula, but severe ultraviolet radiation from nearby massive stars has cleared out the area. This gives astronomers have a rare opportunity to study how a young star like this forms. The Rosette Nebula is located 1,500 light-years away in the constellation of Monoceros.

A duo of Chinese and American astronomers have discovered a young star in the fierce environs of the Rosette Nebula that is ejecting a complex jet of material riddled with knots and bow shocks.

Stripped of its normally opaque surroundings by the intense ultraviolet radiation produced by nearby massive stars, this young stellar object is likely one of the last of its generation in this region of space. Its tenuous state of existence exposes the limitations that young stars?and perhaps even sub-stellar objects such as brown dwarfs and large planets?face in attempting to form in such a violent environment.

A close-up image from this study of the young star, and a striking, newly reprocessed wide-field image of the colorful Rosette Nebula, are available above.

?Most young stars are embedded in very dense molecular clouds, which makes our view of the early stages of star formation normally impossible with optical telescopes,? says Travis Rector of the University of Alaska Anchorage, co-author of a paper on the young stellar object (YSO) in the December 2003 issue of Astrophysical Journal Letters. ?This is one of only a few cases where a protostar is visible, making it a valuable discovery that will be studied in detail.?

Optical images of the jet taken at the WIYN 0.9-meter telescope at the National Science Foundation?s Kitt Peak National Observatory in Arizona show a highly-collimated jet, now known as Rosette HH1, stretching for more than 8,000 astronomical units (1 AU = 150 million kilometers). It contains a prominent knot and hints of others, which can be interpreted as ?bullets? of material being ejected from the rapidly rotating YSO at hypersonic velocities on the order of 2,500 kilometers per second. Bow shocks on the other side of the YSO suggest the existence of a degenerated counterjet extending in the opposite direction.

These interpretations of the jet were bolstered by optical spectroscopy of the jet system taken by co-author Jin Zeng Li of the Chinese Academy of Sciences in Beijing using the 2.16-meter telescope of the National Astronomical Observatories of China.

?If it is indeed a counterjet, it may be the only existing observational evidence of how bipolar jets evolve into monopoles, or at least highly asymmetric jets,? according to Jin Zeng Li. ?This suggests that this infant star has been starved of material as its accretion disk is evaporated, leaving a very low-mass star. In some cases, this process might result in an isolated brown dwarf or planetary mass object, offering a potential evolutionary solution for such lone objects that have been spotted in the Orion Nebula and other nearby hotspots in the Milky Way.?

Located an estimated 1,500 light-years from Earth in the constellation Monoceros, the Rosette Nebula is a spectacular region of ionized hydrogen excavated by the strong stellar winds from hot O- and B-type stars in the center of the young open cluster NGC 2244. It is a region of on-going star formation with an age of about three million years.

Kitt Peak National Observatory is part of the National Optical Astronomy Observatory, Tucson, Ariz., which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the National Science Foundation.

Original Source: NOAO News Release

Posted on by Fraser Cain

First Data from Mars Express

Image credit: ESA

The European Space Agency has gathered a mountain of new data from the Mars Express orbiter, which shows the Red Planet in unprecedented resolution – over the course of the last few weeks it’s gathered more than 100 GB of data. Its photographs show details as fine as sediments left on the bottom of river valleys and dust blowing over the rim of craters. The spacecraft is also detecting water being lost from the Martian atmosphere for the first time. Unfortunately, Mars Express still has yet to detect the British-built Beagle 2 lander, which went missing on December 25, 2003.

Mars Express, ESA?s first mission to Mars, will reach its final orbit on 28 January. It has already been producing stunning results since its first instrument was switched on, on 5 January. The significance of the first data was emphasised by the scientists at a European press conference today at ESA?s Space Operations Centre, Darmstadt, Germany.

“I did not expect to be able to gather together – just one month after the Mars Orbit Insertion of 25 December ? so many happy scientists eager to present their first results”, said Professor David Southwood, ESA Director of Science. One of the main targets of the Mars Express mission is to discover the presence of water in one of its chemical states. Through the initial mapping of the South polar cap on 18 January, OMEGA, the combined camera and infrared spectrometer, has already revealed the presence of water ice and carbon dioxide ice.

This information was confirmed by the PFS, a new high-resolution spectrometer of unprecedented accuracy. The first PFS data also show that the carbon oxide distribution is different in the northern and southern hemispheres of Mars.

The MaRS instrument, a sophisticated radio transmitter and receiver, emitted a first signal successfully on 21 January that was received on Earth through a 70- metre antenna in Australia after it was reflected and scattered from the surface of Mars. This new measurement technique allows the detection of the chemical composition of the Mars atmosphere, ionosphere and surface.

ASPERA, a plasma and energetic neutral atoms analyser, is aiming to answer the fundamental question of whether the solar wind erosion led to the present lack of water on Mars. The preliminary results show a difference in the characteristics between the impact of the solar wind area and the measurement made in the tail of Mars. Another exciting experiment was run by the SPICAM instrument (an ultraviolet and infrared spectrometer) during the first star occultation ever made at Mars. It has simultaneously measured the distribution of the ozone and water vapour, which has never been done before, revealing that there is more water vapour where there is less ozone.

ESA also presented astonishing pictures produced with the High Resolution Stereo Camera (HRSC). They represent the outcome of 1.87 million km2 of Martian surface coverage, and about 100 gigabytes of processed data. This camera was also able to make the longest swath (up to 4000 km) and largest area in combination with high resolution ever taken in the exploration of the Solar System.

This made it possible to create an impressive picture 24 metres long by 1.3 metres high, which was carried through the conference room at the end of the press event by a group of 10-year-old children.

Mrs Edelgard Bulmahn, German Minister for Research and Education, who is also chair of the ESA Council at Ministerial level, said at the press conference: “Europe can be proud of this mission: Mars Express is an enormous success for the European Space Programme.”

Original Source: ESA News Release