HOUSTON - Expedition 31 crew members Gennady Padalka, Joe Acaba and Sergei Revin were welcomed aboard the International Space Station after the hatches opened Thursday at 4:10 a.m. EDT. They docked to the Poisk module at 12:36 a.m. after a two day journey that began in Baikonur Cosmodrome, Kazakhstan aboard a Soyuz TMA-04M spacecraft. After a series of leak and pressure checks, Expedition 31 Commander Oleg Kononenko and Flight Engineers Don Pettit and Andre Kuipers welcomed their new crewmates. The new trio joined the crew for a greeting ceremony and conference with family and mission officials then conducted a safety briefing afterwards. It is now back to business for the current station residents while their newly arrived crew mates begin several days of familiarization tasks as they adjust to life aboard the orbital laboratory. The docking occurred on Acaba’s 45th birthday. He previously visited the station in March 2009 aboard space shuttle Discovery as an STS-119 mission specialist. This is Padalka’s fourth long-duration spaceflight and his third aboard the station. His first mission was aboard Russian Space Station Mir. Revin is making his first trip into space. Padalka is due to become Expedition 32 commander when Kononenko, Pettit and Kuipers undock July 1 in their Soyuz TMA-03M spacecraft after a six-month stay officially ending Expedition 31. Expedition 32 will be complemented two weeks later when it is joined by Flight Engineers Suni Williams, Yuri Malenchenko and Aki Hoshide.
WASHINGTON -- NASA is lending the Galaxy Evolution Explorer (GALEX) to the California Institute of Technology (Caltech) in Pasadena, where the spacecraft will continue its exploration of the cosmos. In a first-of-a-kind move for NASA, a Space Act Agreement was signed May 14 so the university soon can resume spacecraft operations and data management for the mission using private funds.
"NASA sees this as an opportunity to allow the public to continue reaping the benefits from this space asset that NASA developed using federal funding," said Paul Hertz, NASA's Astrophysics Division director at the agency's headquarters in Washington. "This is an excellent example of a public/private partnership that will help further astronomy in the United States."
The Galaxy Evolution Explorer spent about nine years as a NASA mission, probing the sky with its sharp ultraviolet eyes and cataloguing hundreds of millions of galaxies spanning 10 billion years of cosmic time.
"This mission was full of surprises, and now more surprises are sure to come," said Chris Martin, who will remain the mission's principal investigator at Caltech. "It already has scanned a large fraction of the sky, improving our understanding of how galaxies grow and evolve. The astronomy community will continue those studies, in addition to spending more time on stars closer to home in our own galaxy."
The spacecraft was placed in standby mode on Feb. 7 of this year. Soon, Caltech will begin to manage and operate the satellite, working with several international research groups to continue ultraviolet studies of the universe. Projects include cataloguing more galaxies across the entire sky; watching how stars and galaxies change over time; and making deep observations of the stars being surveyed for orbiting planets by NASA's Kepler mission. Data will continue to be made available to the public.
"We're thrilled that the mission will continue on its path of discovery," said Kerry Erickson, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The Galaxy Evolution Explorer is like the 'little engine that could,' forging ahead into unexplored territory."
During its time at NASA, the Galaxy Evolution Explorer made many discoveries involving various types of objects that light up our sky with ultraviolet light. Perhaps the most surprising of these was the discovery of a gargantuan comet-like tail behind a speeding star called Mira. Other finds included catching black holes "red-handed" as they munch away on stars, spying giant rings of new stars around old, presumed dead galaxies, and independently confirming the nature of dark energy.
For astronomers, the most profound shift in their understanding of galaxy evolution came from the mission's findings about a "missing link" population of galaxies. These missing members helped explain how the two major types of galaxies in our universe -- the "red and dead" ellipticals and the blue spirals -- transition from one type to another.
"We were able to trace the life of a galaxy," Martin said. "With the Galaxy Evolution Explorer's ultraviolet detectors, we were able to isolate the small amounts of star formation that are the signatures of galaxies undergoing an evolutionary change. We found that galaxies don't have a single personality, but may change types many times over their lifetime."
The mission also captured a dazzling collection of snapshots, showing everything from ghostly nebulas to a spiral galaxy with huge, spidery arms. A slideshow showing some of the top images can be seen here: http://www.nasa.gov/mission_pages/galex/gallery-index.html .
Under the new agreement, NASA maintains ownership and liability for the Galaxy Evolution Explorer spacecraft. When Caltech completes science activities, it will decommission the spacecraft for NASA. The mission's batteries and solar panels have an expected lifetime of 12 years or more, and the spacecraft will remain in orbit for at least 66 years, after which it will burn-up upon re-entry into Earth's atmosphere. The agreement can be renegotiated when it expires in three years.
Orbital Sciences Corporation in Dulles, Va., which built the spacecraft, will continue performing flight control functions for Caltech associated with monitoring and commanding GALEX and participating in mission planning. Universal Space Network will continue providing the ground stations for communicating with the spacecraft.
A NASA flight test designed to demonstrate the feasibility of inflatable spacecraft technology is coming down to the wire.
The Inflatable Reentry Vehicle Experiment (IRVE-3) is the third in a series of suborbital flight tests of this new technology. It is scheduled to launch from the Wallops Flight Facility on Virginia's Eastern Shore this summer. Technicians will vacuum pack the uninflated 10-foot (3.05 meters) diameter cone of high-tech inner tubes into a 22-inch (56 centimeters) diameter sounding rocket. During the flight test an on board system will inflate the tubes -- stretching a thermal blanket that covers them -to create an aeroshell or heat shield. That heat shield will protect a payload that consists of four segments including the inflation system, steering mechanisms, telemetry equipment and camera gear. After launch the rocket will climb 287 miles (462 kilometers) into the skies over the Atlantic Ocean. The IRVE-3 will separate from the sounding rocket, its aeroshell will get pumped full of nitrogen and then the inflated heat shield and payload will plummet back through Earth's atmosphere. Cameras and instruments will transmit pictures and data to researchers in the Wallops control room the entire time.
Engineers at NASA's Langley Research Center in Hampton, Va., who are overseeing the project, have spent the last three years preparing for the test. They have studied designs, assessed materials in laboratories and wind tunnels and subjected hardware to thermal and pressure loads beyond what it should face in flight. "We have to do all kinds of different testing," said flight systems engineer Carrie Rhoades. "We do high temperature tunnel tests in a number of facilities to check out all different types of thermal protection system materials. For IRVE-3 we know what should work, but for future missions we want to go bigger to carry larger payloads, so we've got to keep testing and trying out different materials." One of the last hurdles before launch was a complete shakedown of the system in NASA Langley's Transonic Dynamics Tunnel, which technicians de-pressurized to mimic upper atmospheric conditions where the aeroshell will be deployed. The team collected data in the control room as they watched the simulated 20-minute flight of IRVE-3. Since a wind tunnel test couldn't replicate the actual flight and separation of the spacecraft from the sounding rocket, the real action began seven minutes and 11 seconds after the test started. That's when cutters -- designed to snip the strings on the bag that contained the packed heat shield -- were supposed to start.
For a brief moment the team held its collective breath when the cutters seem to pause, but then came the sigh of relief as the strings continued to pop open. The inflatable rings and their thermal blanket started unfurling as the inflation system pumped nitrogen in correct sequence. "There are an awful lot of complex systems packed inside the payload on IRVE-3," said Robert Dillman, the chief engineer for IRVE-3. "When it works it looks simple and that's a good thing. But there are a lot of internal parts that have to work together in order to make that simple function achievable." The inflation system test went off without a hitch so the Inflatable Reentry Vehicle Experiment can go to Wallops to be readied for launch. IRVE-3 is one of NASA's many research efforts to develop new technologies to advance space travel. It's part of a project called HIAD for Hypersonic Inflatable Aerodynamic Decelerator -- within NASA's Office of the Chief Technologist's Game Changing Development (GCD) Program. "A HIAD could give NASA more options for future planetary missions or to return cargo to Earth," said Neil Cheatwood, GCD principal investigator for HIAD. "When we go to other planets with an atmosphere, we actually use that atmosphere to slow us down with an aeroshell or an aerodynamic decelerator. But the size of that aeroshell is currently limited. We can't go bigger than the diameter of the launch vehicle." An inflatable heat shield could accommodate larger payloads that could deliver more and heavier science instruments and tools for exploration -- changing the way we explore other worlds.
Engineers checked out the Inflatable Reentry Vehicle Experiment after the successful completion of an inflation system test. The IRVE-3 is scheduled to launch on a sounding rocket later this summer. Credit: NASA/ Sean Smith
PASADENA, Calif. -- Observations from NASA's Wide-field Infrared Survey Explorer (WISE) have led to the best assessment yet of our solar system's population of potentially hazardous asteroids. The results reveal new information about their total numbers, origins and the possible dangers they may pose.
Potentially hazardous asteroids, or PHAs, are a subset of the larger group of near-Earth asteroids. The PHAs have the closest orbits to Earth's, coming within five million miles (about eight million kilometers), and they are big enough to survive passing through Earth's atmosphere and cause damage on a regional, or greater, scale.
The new results come from the asteroid-hunting portion of the WISE mission, called NEOWISE. The project sampled 107 PHAs to make predictions about the entire population as a whole. Findings indicate there are roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330 feet (about 100 meters). So far, an estimated 20 to 30 percent of these objects have been found.
While previous estimates of PHAs predicted similar numbers, they were rough approximations. NEOWISE has generated a more credible estimate of the objects' total numbers and sizes.
"The NEOWISE analysis shows us we've made a good start at finding those objects that truly represent an impact hazard to Earth," said Lindley Johnson, program executive for the Near-Earth Object Observation Program at NASA Headquarters in Washington. "But we've many more to find, and it will take a concerted effort during the next couple of decades to find all of them that could do serious damage or be a mission destination in the future."
The new analysis also suggests that about twice as many PHAs as previously thought are likely to reside in "lower-inclination" orbits, which are more aligned with the plane of Earth's orbit. In addition, these lower-inclination objects appear to be somewhat brighter and smaller than the other near-Earth asteroids that spend more time far away from Earth. A possible explanation is that many of the PHAs may have originated from a collision between two asteroids in the main belt lying between Mars and Jupiter. A larger body with a low-inclination orbit may have broken up in the main belt, causing some of the fragments to drift into orbits closer to Earth and eventually become PHAs.
Asteroids with lower-inclination orbits would be more likely to encounter Earth and would be easier to reach. The results therefore suggest more near-Earth objects might be available for future robotic or human missions.
"NASA's NEOWISE project, which wasn't originally planned as part of WISE, has turned out to be a huge bonus," said Amy Mainzer, NEOWISE principal investigator, at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Everything we can learn about these objects helps us understand their origins and fate. Our team was surprised to find the overabundance of low-inclination PHAs. Because they will tend to make more close approaches to Earth, these targets can provide the best opportunities for the next generation of human and robotic exploration."
The discovery that many PHAs tend to be bright says something about their composition; they are more likely to be either stony, like granite, or metallic. This type of information is important in assessing the space rocks' potential hazards to Earth. The composition of the bodies would affect how quickly they might burn up in our atmosphere if an encounter were to take place.
The NEOWISE results have been accepted for publication in the Astrophysical Journal.
The WISE spacecraft scanned the sky twice in infrared light before entering hibernation mode in early 2011. It catalogued hundreds of millions of objects, including super-luminous galaxies, stellar nurseries and closer-to-home asteroids. The NEOWISE project snapped images of about 600 near-Earth asteroids, about 135 of which were new discoveries. Because the telescope detected the infrared light, or heat, of asteroids, it was able to pick up both light and dark objects, resulting in a more representative look at the entire population. The infrared data allowed astronomers to make good measurements of the asteroids' diameters and, when combined with visible light observations, how much sunlight they reflect.
JPL manages, and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing and archiving take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.
GREENBELT, Md - Observations with NASA's Chandra X-ray Observatory have provided the first X-ray evidence of a supernova shock wave breaking through a cocoon of gas surrounding the star that exploded. This discovery may help astronomers understand why some supernovas are much more powerful than others. On Nov. 3, 2010, a supernova was discovered in the galaxy UGC 5189A, located about 160 million light years away. Using data from the All Sky Automated Survey telescope in Hawaii taken earlier, astronomers determined this supernova exploded in early October 2010 (in Earth's time-frame). This composite image of UGC 5189A shows X-ray data from Chandra in purple and optical data from Hubble Space Telescope in red, green and blue. SN 2010jl is the very bright X-ray source near the top of the galaxy. A team of researchers used Chandra to observe this supernova in December 2010 and again in October 2011. The supernova was one of the most luminous that has ever been detected in X-rays. In optical light, SN 2010jl was about ten times more luminous than a typical supernova resulting from the collapse of a massive star, adding to the class of very luminous supernovas that have been discovered recently with optical surveys. Different explanations have been proposed to explain these energetic supernovas including (1) the interaction of the supernova's blast wave with a dense shell of matter around the pre-supernova star, (2) radioactivity resulting from a pair-instability supernova (triggered by the conversion of gamma rays into particle and anti-particle pairs), and (3) emission powered by a neutron star with an unusually powerful magnetic field. In the first Chandra observation of SN 2010jl, the X-rays from the explosion's blast wave were strongly absorbed by a cocoon of dense gas around the supernova. This cocoon was formed by gas blown away from the massive star before it exploded. In the second observation taken almost a year later, there is much less absorption of X-ray emission, indicating that the blast wave from the explosion has broken out of the surrounding cocoon. The Chandra data show that the gas emitting the X-rays has a very high temperature -- greater than 100 million degrees Kelvin – strong evidence that it has been heated by the supernova blast wave. The energy distribution, or spectrum, of SN 2010jl in optical light reveals features that the researchers think are explained by the following scenario: matter around the supernova has been heated and ionized (electrons stripped from atoms) by X-rays generated when the blast wave plows through this material. While this type of interaction has been proposed before, the new observations directly show, for the first time, that this is happening. This discovery therefore supports the idea that some of the unusually luminous supernovas are caused by the blast wave from their explosion ramming into the material around it. In a rare example of a cosmic coincidence, analysis of the X-rays from the supernova shows that there is a second unrelated source at almost the same location as the supernova. These two sources strongly overlap one another as seen on the sky. This second source is likely to be an ultraluminous X-ray source, possibly containing an unusually heavy stellar-mass black hole, or an intermediate mass black hole. These results were published in a paper appearing in the May 1st, 2012 issue of The Astrophysical Journal Letters. The authors were Poonam Chandra (Royal Military College of Canada, Kingston, Canada), Roger Chevalier and Christopher Irwin (University of Virginia, Charlottsville, VA), Nikolai Chugai (Institute of Astronomy of Russian Academy of Sciences, Moscow, Russia), Claes Fransson (Stockholm University, Sweden), and Alicia Soderberg (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA).
MOSCOW - NASA astronaut Joe Acaba and Russian cosmonauts Gennady Padalka and Sergei Revin launched aboard a Soyuz spacecraft from the Baikonur Cosmodrome in Kazakhstan at 11:01 p.m. EDT on Monday (9:01 a.m. Tuesday, Kazakhstan time), beginning a two-day flight to the International Space Station. › View video of launch Less than 10 minutes after launch their Soyuz TMA-04M spacecraft reached orbit, and its antennas and solar arrays deployed. The trio will dock to the station’s Poisk Mini-Research Module at 12:38 a.m. Thursday, bringing the Expedition 31 crew to its full six-member complement. Acaba, Revin and Padalka will join the current station residents, Commander Oleg Kononenko and Flight Engineers Don Pettit and Andre Kuipers, and begin a four-month tour of duty aboard the orbiting complex. Kononenko, Pettit and Kuipers, who arrived Dec. 23 aboard their Soyuz TMA-03M spacecraft, will return home on July 1, marking the start of Expedition 32 under the command of Padalka. About two weeks afterward, NASA astronaut Suni Williams, Russian cosmonaut Yuri Malenchenko and Japan Aerospace Exploration Agency astronaut Aki Hoshide will arrive at the orbiting complex to round out the Expedition 32 crew. Acaba previously visited the station in March 2009 as a mission specialist for the STS-119 crew aboard space shuttle Discovery. The crew delivered the final set of solar array wings and truss element to complete the station’s electricity-generating system. Acaba accumulated 12 hours, 57 minutes of spacewalk time during two excursions outside the station during STS-119. This will mark Padalka’s fourth long-duration spaceflight and his third aboard the station. He previously completed 198 days in space aboard Mir in February 1999 and served as station commander for Expedition 9 in 2004 and Expedition 19/20 in 2009. Revin is making his first trip into space. Also on board with the crew was a small "Smokey Bear" plush toy serving as the traditional Soyuz "talisman." Smokey Bear is the U.S. national symbol for wildfire prevention. Prior to the flight, Acaba explained he proposed flying Smokey Bear in an effort to raise awareness of human-caused wildfires. Acaba, an avid outdoorsman, holds two degrees in geology and served as an environmental education awareness promoter while in the U.S. Peace Corps.
FRENCH GUIANA - Arianespace provided another on-time Ariane 5 launch tonight by orbiting a pair of telecommunications spacecraft at the service of Asian region operators on a mission that included multiple numerical milestones for the company and its customers.
Lifting off from the Spaceport in French Guiana, Arianespace’s heavy-lift workhorse delivered the JCSAT-13 and VINASAT-2 relay platforms into geostationary transfer orbits on the 48th consecutive success for Ariane 5.
The two passengers lofted on today’s mission were the 100th and 101st commercial geostationary communications satellites from Lockheed Martin Space Systems, as well as the 42nd and 43rd platforms from this U.S. spacecraft manufacturer launched by Arianespace. Both JCSAT-13 and VINASAT-2 are similar in overall configuration, as they use Lockheed Martin’s A2100AX and A2100 spacecraft platform designs, respectively.
According to Arianespace Chairman & CEO Jean-Yves Le Gall, this flight also enabled his company to surpass the 300th mark for the total number of primary satellite passengers launched in its operations from French Guiana – a count that does not include some 50 additional auxiliary or secondary payloads.
Le Gall also noted the mission continues a 23-year relationship of Japan’s SKY Perfect JSAT Corporation with Arianespace, which began in 1989 when JCSAT-1 was orbited on an Ariane 4. With tonight’s flight, JCSAT-13 become the 27th satellite that Japanese operators have entrusted to commercial launch services with the Ariane family of vehicles.
JCSAT-13 is to be positioned in geostationary orbit at 124 deg. East, providing direct TV broadcast links to all of Japan as a replacement satellite for JCSAT-4A, and its capacity will meet satellite relay coverage demands in Southeast Asia. Weighing nearly 4,530 kg. at launch, JCSAT-13 is equipped with 44 Ku-band transponders and has a design life exceeding 15 years. VINASAT-2 is the second satellite launched by Arianespace for operation by the Vietnam Posts and Telecommunications Group, and follows the lofting of VINASAT-1 on an Ariane 5 flight in April 2008. Equipped with 24 Ku-band transponders to handle radio, television and telephone links for all of Vietnam, VINASAT-2 had a liftoff mass of approximately 2,970 kg. and will operate from an orbital position at 131.8 deg. East during a design lifetime of 15-plus years.
“This was a very beautiful flight,” commented Joe Rickers, the President of Commercial Systems at Lockheed Martin Space Systems, in a speech at the launch control center. “I want to congratulate Arianespace and Jean-Yves Le Gall, along with all those [at the Spaceport] who support the launches: your record of success speaks for itself.”
Arianespace is keeping up the Ariane 5 launch pace this year, as today’s second heavy-lift launch of 2012 will be followed by the next flight on July 19. In another dual-payload flight, the workhorse will carry the Space Systems/Loral-produced EchoStar XVII high-throughput telecommunications platform for Hughes Network Systems, along with the Meteosat Second Generation-3 (MSG-3) weather satellite for EUMETSAT that was built by a Thales Alenia Space-led industry consortium.
KENNEDY SPACE CENTER - The Vehicle Assembly Building at NASA's Kennedy Space Center in Florida has been a landmark to the technological advancements of sending men to the moon and astronauts into space for more than 45 years. But the VAB, as it is best known, is due for major renovations to continue processing launch vehicles and support the subsequent launching of a new generation of astronauts into orbit and deeper into space than ever before. "This is home improvement, VAB style," said Jose Lopez, who is managing the effort to refurbish a structure that was once the biggest in the world. "We're going for more flexibility and reliability with modern equipment. That building has many systems that haven't been touched up since it was built (in 1965)." Although the work is massive simply because of the scale of the VAB, Lopez said now is the time to do it and take advantage of the pause in rocket processing that is to end in a couple years. "When the shuttle program was in place, you couldn't take down the cranes for a long period of time, or take on heavy infrastructure projects," Lopez said. Before another generation of rocket processing kicks in, Lopez said, the VAB must be outfitted with everything it needs to host these rockets and spacecraft assembly for another 40 years. The effort will touch most areas of the architectural behemoth in one way or other. For instance, High Bay 3 will see the seven work platforms designed for the Apollo/Saturn V removed. In their place will be a series of 10 platforms that can be relocated and fitted with inserts designed for processing different kinds of rockets. Like everything else inside the VAB, the platforms are not run-of-the-mill items. They are expected to weigh about 90,000 pounds and be outfitted with commodities essential for rockets, such as nitrogen and helium along with electrical and networking cables. Simply put, no longer will a high bay be suitable for only one kind of rocket design. "If you can fit in the big rocket, you can definitely fit in the smaller rockets,” Lopez said. The VAB is slated to host NASA's Space Launch System, or SLS, as it is readied for test flights in 2017 and 2021. The SLS will rival the Saturn V for sheer size and power and is designed for several variations that the platforms would have to accommodate. Commercial companies with much smaller rockets also are expected to use the VAB's unique facilities. "The main thing we're doing there is an evolvable approach where we can handle any one of these SLS vehicles, but also handle any of the commercial vehicles," said Scott Colloredo, chief architect of the Ground Systems Development and Operations Program that is overseeing the VAB modifications. "By supporting one, it helps us to support the other." The five primary overhead cranes in the VAB will see their antiquated control systems modernized, too. The cranes, anchored to the VAB's framework at the top of the structure, were used to lift the shuttles and rocket stages from the floor of the transfer aisle to their place on the launch platforms. They routinely hoisted the 100-ton shuttles more than 16 stories off the ground safely and lowered them onto the side of the external fuel tank for launch. Two of the cranes can lift 325 tons, another two are rated for 250-ton loads and the fifth one is designed to hold 175 tons. They will be crucial again in the future to stack the SLS components into a launch configuration. The doors, the largest in the world, are due for new braking systems and other modifications that will reduce wear-and-tear on the tracks and systems. The renovation calls for removing a great deal of the infrastructure inside the VAB, some of which was installed when the structure was built in 1965. New systems, all up to modern building and safety codes, are to be installed. More than 50 miles of Apollo-era cabling will be removed during the work and replaced with modern lines. About 70,000 feet of cabling already has come out. In some cases, that means replacing thick bundles of copper wiring with a few fiber-optic lines no wider than a pinky finger. The fire suppression system has corroded in many important areas and is not big enough under current regulations. So its vast network of pipes, spigots and pumps, will be taken out entirely beginning next year and replaced with new equipment and piping. The work should be finished by the end of 2014, Lopez said. There is plenty of evidence that other water and drainage pipes in the VAB are also corroding, so they will be replaced, along with boilers and chillers that feed hot and cold water into the facility. Battery backups for the electrical system also are slated for replacement. The renovation is focusing on the building interior systems, but the building itself is in very good shape. The work would have had to be done at some point soon whether rockets were being processed or not, Lopez said. Doing it all while keeping the structure's systems up and able to handle normal processing demands would have been an exceptional and expensive challenge, though. "It would have been like putting a new car engine in your trunk while keeping the same engine in the front still going," Lopez said.
GREENBELT, Md - This mottled landscape showing the impact crater Tycho is among the most violent-looking places on our moon. Astronomers didn't aim NASA's Hubble Space Telescope to study Tycho, however. The image was taken in preparation to observe the transit of Venus across the sun's face on June 5-6. Hubble cannot look at the sun directly, so astronomers are planning to point the telescope at the Earth's moon, using it as a mirror to capture reflected sunlight and isolate the small fraction of the light that passes through Venus's atmosphere. Imprinted on that small amount of light are the fingerprints of the planet’s atmospheric makeup. These observations will mimic a technique that is already being used to sample the atmospheres of giant planets outside our solar system passing in front of their stars. In the case of the Venus transit observations, astronomers already know the chemical makeup of Venus's atmosphere, and that it does not show signs of life on the planet. But the Venus transit will be used to test whether this technique will have a chance of detecting the very faint fingerprints of an Earth-like planet, even one that might be habitable for life, outside our solar system that similarly transits its own star. , Venus is an excellent proxy because it is similar in size and mass to our planet. The astronomers will use an arsenal of Hubble instruments, the Advanced Camera for Surveys, Wide Field Camera 3, and Space Telescope Imaging Spectrograph, to view the transit in a range of wavelengths, from ultraviolet to near-infrared light. During the transit, Hubble will snap images and perform spectroscopy, dividing the sunlight into its constituent colors, which could yield information about the makeup of Venus's atmosphere. Hubble will observe the moon for seven hours, before, during, and after the transit so the astronomers can compare the data. Astronomers need the long observation because they are looking for extremely faint spectral signatures. Only 1/100,000th of the sunlight will filter through Venus's atmosphere and be reflected off the moon. This image, taken with Hubble's Advanced Camera for Surveys, reveals lunar features as small as roughly 560 feet (170 meters) across. The large "bulls-eye" near the top of the picture is the impact crater, caused by an asteroid strike about 100 million years ago. The bright trails radiating from the crater were formed by material ejected from the impact area during the asteroid collision. Tycho is about 50 miles (80 kilometers) wide and is circled by a rim of material rising almost 3 miles (5 kilometers) above the crater floor. The image measures 430 miles (700 kilometers) across, which is slightly larger than New Mexico. Because the astronomers only have one shot at observing the transit, they had to carefully plan how the study would be carried out. Part of their planning included the test observations of the moon, made on Jan. 11, 2012, as shown in the release image. Hubble will need to be locked onto the same location on the moon for more than seven hours, the transit's duration. For roughly 40 minutes of each 96-minute orbit of Hubble around the Earth, the Earth occults Hubble's view of the moon. So, during the test observations, the astronomers wanted to make sure they could point Hubble to precisely the same target area. This is the last time this century sky watchers can view Venus passing in front of the sun. The next transit won't happen until 2117. Venus transits occur in pairs, separated by eight years. The last event was witnessed in 2004. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
GREENBELT, Md - For the last few decades, space scientists have generally accepted that the bubble of gas and magnetic fields generated by the sun – known as the heliosphere – moves through space, creating three distinct boundary layers that culminate in an outermost bow shock. This shock is similar to the sonic boom created ahead of a supersonic jet. Earth itself certainly has one of these bow shocks on the sunward side of its magnetic environment, as do most other planets and many stars. A collection of new data from NASA's Interstellar Boundary Explorer (IBEX), however, now indicate that the sun does not have a bow shock. In a paper appearing online in Science Express on May 10, 2012, scientists compile data from IBEX, NASA's twin Voyager spacecraft, and computer models to show that the heliosphere just isn't moving fast enough to create a bow shock in the tenuous and highly magnetized region in our local part of the galaxy. "IBEX gives a global view. It shows the whole of this region," says Eric Christian who is the mission scientist for IBEX at NASA's Goddard Space Flight Center in Greenbelt, Md. and who was formerly the program scientist for Voyager. "At the same time the Voyager spacecraft are actually there, in situ, measuring its environment at two locations. The combination of IBEX and Voyager gives you great science and now the new IBEX results strongly indicate that there is no bow shock." Since the 1980s, the boundaries of the heliosphere have largely been assumed to be a series of three. The first is a fairly spherical boundary called the termination shock -- the point where the solar wind streaming from the sun slows down below supersonic speeds. From there the wind continues more slowly until it collides with the material in the rest of the galaxy and is pushed back, deflecting around the outskirts of the heliosphere, streaming back toward the tail of the moving bubble. This second boundary is called the heliopause. The third boundary was thought to be the bow shock, formed as the heliosphere plowed its way through the local galactic cloud the same way a supersonic jet pushes aside the air as it moves. The two Voyager spacecraft have confirmed the existence of the first boundary, and have seen evidence for the second as they move toward it. However, each Voyager spacecraft has seen different things on their respective trips – one moving in a more northerly direction, one moving more to the south. They've encountered different regions at different distances from the sun, suggesting the very shape of the heliosphere is squashed and asymmetrical. Scientists believe this asymmetry is caused by the force and direction of magnetic fields ramming into the heliosphere from outside, the same way a hand pushing on a balloon will force it out of shape. This was the first clue that there's a strong magnetic field exerting pressure on the outskirts of the solar system. Independently, IBEX has seen a well-defined band, or ribbon, at the edge of the heliosphere, believed to be defined by this external magnetic field. Other studies from IBEX have helped quantify the magnitude of the magnetic field, showing that it is on the strong end of what was previously thought possible. "We've seen one after another signature of a very strong magnetic field in the galactic environment," says Nathan Schwadron, a space scientist at the University of New Hampshire in Durham who is one of the authors on the paper. "That magnetic field influences the structure of the heliosphere and the boundaries themselves. That leads to a whole new paradigm." Along with increased evidence for a strong external magnetic field, IBEX has also provided a new measurement for the speed of the heliosphere itself with respect to the local cloud. "We recently analyzed two years worth of IBEX data, and they showed that the speed of the heliosphere – with respect to the local cloud of material – is only 52,000 miles per hour, instead of the previously believed 59,000," says David McComas at the Southwest Research Institute in San Antonio, Texas, who is first author on this paper and also the principal investigator for IBEX. "That might not seem like a huge difference, but it translates to a quarter less pressure exerted on the boundaries of the heliosphere. This means there's a very different interaction, a much weaker interaction, than previously thought." In essence, it means that, like an airplane going too slowly to produce a sonic boom, the heliosphere isn't moving fast enough to create a bow shock, given the density and pressures of the material its moving through. The heliosphere's boundaries lie roughly 10 billion miles away from Earth, but are nonetheless crucial for understanding our place in the universe. Indeed, the heliopause provides some protection for our solar system from the harsh, radiation environment surrounding it. By knowing the nature of these boundaries, scientists can start to better understand the propagation of particles that do have enough energy and speed to make it into our environment. As scientists incorporate this substantive new understanding into their physical models, they will also be waiting for more evidence from both IBEX and the Voyagers, which they hope will continue to send back observations for many years to come. "Imagine the point at which Voyager crosses the threshold of the heliopause and either does or does not see what IBEX is predicting," says Schwadron. "There will be enormous opportunities for scientific advancement."