Monday, December 20, 2010
A Lunar Eclipse on Solstice Day
Sometime after sunset tonight, the Moon will go dark. This total lunar eclipse, where the entire Moon is engulfed in the shadow of the Earth, will be visible from all of North America, while the partial phase of this eclipse will be visible throughout much of the rest of the world. Observers on North America's east coast will have to wait until after midnight for totality to begin, while west coasters should be able to see a fully darkened moon before midnight. Pictured above is a digital prediction, in image form, for how the Moon and the surrounding sky could appear near maximum darkness. Rolling your cursor over the image will bring up labels. Parts of the Moon entering the circle labeled umbra will appear the darkest since the Sun there will be completely blocked by the Earth. Parts of the Moon entering the circle labeled penumbra will be exposed to some direct sunlight, and so shine by some degree by reflected light. The diminished glare of the normally full Moon will allow unusually good viewings of nearby celestial wonders such as the supernova remnant Simeis 147, the open star cluster M35, and the Crab Nebula M1. By coincidence this eclipse occurs on the day with the shortest amount of daylight in the northern hemisphere -- the Winter Solstice. This solstice eclipse is the first in 456 years, although so far it appears that no one has figured out when the next solstice eclipse will be.
A Galaxy for Everyone
This collage of galaxies from NASA's Wide-Field Infrared Survey Explorer, or WISE, showcases the many "flavors" that galaxies come in, from star-studded spirals to bulging ellipticals to those paired with other companion galaxies. The WISE team put this collage together to celebrate the anniversary of the mission's launch on Dec. 14, 2009.
After launch and a one-month checkout period, WISE began mapping the sky in infrared light. By July of this year, the entire sky had been surveyed, detecting hundreds of millions of objects, including the galaxies pictured here. In October of this year, after scanning the sky about one-and–a-half times, the spacecraft ran out of its frozen coolant, as planned. With its two shortest-wavelength infrared detectors still operational, the mission continues to survey the sky, focusing primarily on asteroids and comets.
NGC 300 is seen in the image in the upper left panel. This is a textbook spiral galaxy. In fact, it is such a good representation of a spiral galaxy that astronomers have studied it in great detail to learn about the structure of all spirals in general. Infrared images like this one from WISE show astronomers where areas of gas and warm dust are concentrated -- features that cannot be seen in visible light. At about 39,000 light-years across, NGC 300 is only about 40 percent the size of the Milky Way galaxy.
Download full size image International Astronauts Arrive At Space Station
The Russian space agency, Roscosmos, said a shuttle carrying Russian, Italian and American astronauts successfully docked with the International Space Station on Friday, after Russian space control had lost contact with it for several hours on Thursday.
The Soyuz TMA-20 docked two days after blasting off from the Baikonur Cosmodrome on the Kazakh steppe. The shuttle carried NASA astronaut Catherine Coleman, Russian cosmonaut Dmitry Kondratyev and the European Space
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Agency's Paolo Nespoli of Italy.
"The approach and the docking of the ship with the station was carried out under the control of the space command center," according to a statement found on the Roscosmos website www.roscosmos.ru.
The Russian news agency Interfax reported late Thursday that Russia's space command center had lost contact with the spaceship, but hours later information from the craft had starting flowing again.
The Soyuz flight is one of the last before NASA retires its space shuttle fleet, leaving astronauts completely reliant on the Russian spacecrafts for missions to the International Space Station.
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Image Caption: TMA-20 mission patch (Credit: Roscosmos)
The Soyuz TMA-20 docked two days after blasting off from the Baikonur Cosmodrome on the Kazakh steppe. The shuttle carried NASA astronaut Catherine Coleman, Russian cosmonaut Dmitry Kondratyev and the European Space
Click here to find out more!
Agency's Paolo Nespoli of Italy.
"The approach and the docking of the ship with the station was carried out under the control of the space command center," according to a statement found on the Roscosmos website www.roscosmos.ru.
The Russian news agency Interfax reported late Thursday that Russia's space command center had lost contact with the spaceship, but hours later information from the craft had starting flowing again.
The Soyuz flight is one of the last before NASA retires its space shuttle fleet, leaving astronauts completely reliant on the Russian spacecrafts for missions to the International Space Station.
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Image Caption: TMA-20 mission patch (Credit: Roscosmos)
NASA Fuels Space Shuttle Discovery to Test Damaged Tank
HOUSTON — NASA pumped hundreds of thousands of gallons of super-cold propellants into space shuttle Discovery's external fuel tank Friday morning to test why it had developed cracks along two support beams during a launch attempt last month.
The so-called got underway at 7 a.m. EST (1200 GMT), when the three-hour fueling process began. It is scheduled to continue until 2:25 p.m. EST (1925 GMT) when the test's simulated launch countdown ends after a five-minute hold at the T-minus 31 second mark.
Sensors installed on the tank will continue to collect data as the tank is emptied this afternoon and then continue to record the tank's performance through Saturday as it warms to ambient temperature.
The test, which also serves to verify the repairs technicians made to the 154-foot tall tank, was proceeding without any noticeable issues. Results from the test were not expected immediately. Managers and engineers will review the data generated by the exercise before determining the next course of action.
"It looks like we're getting good data," said Mike Moses, NASA's space shuttle launch integration manager at the Kennedy Space Center in Cape Canaveral, Fla. "Like anything with a hazardous operation, it is nice and boring today, which is a good thing. Everything is looking like it is supposed to."
Discovery no earlier than Feb. 3, 2011 on its final flight to space before being retired. But first, the shuttle will be rolled off its launch pad and returned to the 52-story tall Vehicle Assembly Building (VAB) to undergo further tank inspections.
Cracked stringers
Friday's tanking test will help shuttle engineers determine what caused two 21-foot-long, U-shaped aluminum brackets, called stringers, to crack during the lead-up to a Nov. 5 attempt to launch Discovery on its STS-133 mission. That launch attempt was called off not because of the cracks but rather due to an unrelated gaseous hydrogen leak that emanated from a cable connecting the tank to the pad.
The hydrogen leak was subsequently traced back to a hardware alignment issue and was corrected. During Friday's test, no hydrogen was detected escaping from the umbilical.
During the Nov. 5 launch attempt, the cracked stringers caused their overlying foam insulation to crack, which is how NASA initially discovered the damage in the hours following the foiled countdown. In addition to the cracked beams posing a potential structural concern, cracks in the foam could cause the insulation to fall off during the shuttle's climb to orbit, creating a risk it might impact and damage the orbiter's heat shield.
In February 2003, falling foam from the fuel tank hit the space shuttle Columbia's left wing, damaging its leading edge. The impact ultimately led to the loss of the vehicle and its seven-person crew when Columbia re-entered Earth's atmosphere at the conclusion of its STS-107 mission.
Though NASA has encountered cracks in a tank's stringers before, they have always shown up during its assembly. This was the first time that cracks were found while the space shuttle was on the launch pad, leading engineers to wonder if they missed something during the beams' fabrication or installation.
"Either the stringer was the cause of the problem, that there was some assembly tolerance, some build up of stress in that part, or a crack that went through the system and we didn't see, that caused this stringer to break and so it is an isolated event — it's this stringer and that's the problem — or the... stringer is a victim here and the design has a problem, the tank itself has a bigger issue to it, the loading had a problem and that there is something wrong generically that is causing stress to be concentrated in this area that's never been there before," explained Moses.
Because engineers have not yet discovered the root cause for the damage, managers called for Friday's tanking test to gather more data.
Instrumented tank
Shuttle technicians outfitted the tank's ribbed midsection, or intertank region, with nearly 90 instruments, including strain gauges to precisely record movement and temperatures as the tank chilled and warmed again during the test's fuel loading and emptying process.
The orange-brown tank holds more than 500,000 gallons of super-cold liquid oxygen at minus 297 degrees Fahrenheit and liquid hydrogen at minus 423 degrees F. Earlier measurements have shown that these cryogenic propellants cause the tank to shrink by about half an inch.
The test will provide more nasa information about how the tank performs during fueling, as well as verify the repairs made to the cracked stringers. Technicians installed new sections of metal, called "doublers" because they are twice as thick as the original stringer metal, to replace the tops of the two cracked stringers.
"The point of the [test] is to gather performance data on the tank," Moses said. "We have stringers instrumented in the repair area so we can look and see how the repair performs under a cryo load. We have stringers instrumented next to that repair that aren't damaged, so we can see how they perform... and then on the opposite side of the tank, we've instrumented stringers to kind of go to a control-type theory, to say over here in a completely different area, here's how the tank performs."
The big picture moving forward
According to Moses, the test will generate more than five or six terabytes — 5,000 to 6,000 gigabytes — of data.
"All of that is going to be post-processed and shipped to the Michoud Assembly Facility [in Louisiana] and Marshall Space Flight Center [in Alabama] where the analysis will be done," said Moses. "That data will be there tonight. The expectation is by the weekend, we'll have reviewed all of that."
The data needs to be verified, though not analyzed, before can be rolled back to its assembly hangar for further analysis and to be prepared for launch.
"We've decided to roll back to the VAB and so one of the go-no go's for that rollback is a report from that instrumentation team that they are happy with the data. That doesn't mean we've analyzed it and the results of the data are good but that we've captured good data," Moses explained.
"We can then cut the wiring and de-configure the vehicle and be ready to rollback," he said.
Discovery is tentatively scheduled to begin its 3.4 mile (5.5 km) journey back to the VAB just after midnight on Tuesday, Dec. 21. Once inside the building, the fuel tank will undergo X-ray scans to examine the stringers along its backside. The tanking test instrumentation will also be removed, and — along with the installation of any modifications called for by the test data — the tank will be readied again for launch.
Meanwhile, shuttle managers will begin seeing the results from the test.
"Our big picture plan is that on Monday, Tuesday, Wednesday next week we'll start to get the results of that data in," said Moses. "It is going to take a while before we get all the fine details, but the big picture... all that's going to happen next week."
If all proceeds smoothly, Discovery will be returned to the launch pad in mid-January.
"We're going to have folks working around the country right through the Christmas holiday here to be ready to potentially fly again in this February launch window when it comes around," said Moses.
Discovery's next opportunity to embark on its 39th and final mission is scheduled for no earlier than 1:37 a.m. EST (0637 GMT) on Feb. 3. The shuttle's planned 11-day trip will deliver a storage room and Robonaut 2, a humanoid robot, to the International Space Station. Two spacewalks are also planned.
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NASA Spacecraft Provides Travel Tips for Mars Rover
Opportunity's view of Santa Maria crater NASA's Mars Exploration Rover Opportunity used its navigation camera to record this view of Santa Maria crater at the end of a drive during the 2,450th Martian day, or sol, of the rover's work on Mars (Dec. 15, 2010). Image credit: NASA/JPL-Caltech
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Map indicates geological units in a region of MarsThis map indicates geological units in the region of Mars around a smaller area where NASA's Mars Exploration Rover Opportunity has driven from early 2004 through late 2010. Image credit: NASA/JPL-Caltech/JHU-APL/WUSTL
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Orbital observations of crater on Mars rover's routeNASA's Mars Exploration Rover Opportunity approached Santa Maria Crater in December 2010. With a diameter of about 90 meters (295 feet), this crater is slightly smaller than Endurance Crater, which Opportunity explored for about half a year in 2004. Image credit: NASA/JPL-Caltech/Univ. of Arizona
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SAN FRANCISCO -- NASA's Mars Opportunity rover is getting important tips from an orbiting spacecraft as it explores areas that might hold clues about past Martian environments.
Researchers are using a mineral-mapping instrument aboard NASA's Mars Reconnaissance Orbiter to help the rover investigate a large ancient crater called Endeavour. The orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is providing maps of minerals at Endeavour's rim that are helping the team choose which area to explore first and where to go from there. As Mars Reconnaissance Orbiter orbits more than 241 kilometers high (150 miles), the CRISM instrument provides mapping information for mineral exposures on the surface as small as a tennis court.
"This is the first time mineral detections from orbit are being used in tactical decisions about where to drive on Mars," said Ray Arvidson of Washington University in St. Louis. Arvidson is the deputy principal investigator for the Spirit and Opportunity rovers and a co-investigator for CRISM.
Opportunity's science team chose to begin driving the rover toward the 22.5-kilometer-wide (14-mile-wide) crater in 2008, after four years studying other sites in what initially was planned as a three-month mission. The rover has traveled approximately nine miles since setting out for Endeavour crater. It will take several months to reach it.
The team plans for Opportunity's exploration of Endeavour to begin at a rim fragment called Cape York. That feature is too low to be visible by the rover, but appears from orbit to be nearly surrounded by water-bearing minerals. The planned route then turns southward toward a higher rim fragment called Cape Tribulation, where CRISM has detected a class of clay minerals not investigated yet by a ground mission. Spacecraft orbiting Mars found these minerals to be widespread on the planet. The presence of clay minerals at Endeavour suggests an earlier and milder wet environment than the very acidic, wet one indicated by previous evidence found by Opportunity.
"We used to have a disconnect between the scale of identifying minerals from orbit and what missions on the surface could examine," said CRISM team member Janice Bishop of NASA's Ames Research Center in Moffett Field, Calif., and the SETI Institute of Mountain View, Calif. "Now, rovers are driving farther and orbital footprints are getting smaller."
Ten years ago, an imaging spectrometer on NASA's Mars Global Surveyor orbiter found an Oklahoma-sized area with a type of the mineral hematite exposed. This discovery motivated selection of the area as Opportunity's 2004 landing site. Each pixel footprint for that spectrometer was 3.2 kilometers (2 miles) across. CRISM resolves areas about 18 meters (60 feet) across. Last fall, the instrument began using a pixel-overlap technique that provided even better resolution.
Opportunity has just reached a 90-meter-diameter crater (300-foot) called Santa Maria, where CRISM detected a patch of ground with indications of water bound into the mineral. Opportunity will conduct a science campaign at the crater for the next several weeks to compare the ground results to the orbital indications.
"Opportunity has driven farther in the past Martian year than in any previous one," said John Callas, Mars Exploration Rover project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
A Martian year lasts approximately 23 months. During the past Martian year, Opportunity covered more than 12 kilometers (7.5 miles) of the mission's 26 total kilometers (16 miles) traveled since it landed in January 2004. The rover has returned more than 141,000 images.
Mars Reconnaissance Orbiter reached the Red Planet in 2006 to begin a two-year primary science mission. Its data show Mars had diverse wet environments at many locations for differing durations during the planet's history, and climate-change cycles persist into the present era. The mission has returned more planetary data than all other Mars missions combined.
JPL manages the Mars Exploration Rovers and the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., manages CRISM.
For more information about Mars missions, visit: http://www.nasa.gov/mars .
Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov
Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov
Rachel Hoover 650-604-0643
Ames Research Center, Moffett Field, Calif.
rachel.hoover@nasa.gov
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