NASA image of the day (imatge del dia, NASA)

Hundreds of fires burned across western Russia on August 2, 2010, but it is the smoke that conveys the magnitude of the disaster in this true-color image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Dense gray-brown smoke extends across the width of this image, a distance of about 1,700 kilometers (1,000 miles). The smoke clearly continues both east and west beyond the edge of the image, and is visible in both previous and successive orbits of the Terra satellite. The smoke is so thick that it is not possible to see the ground beneath it. Image Credit: NASA/MODIS Rapid Response

This gimbal rig, formally known as the MASTIF, or Multiple Axis Space Test Inertia Facility, was engineered to simulate the tumbling and rolling motions of a space capsule and train the Mercury astronauts to control roll, pitch and yaw by activating nitrogen jets, used as brakes and bring the vehicle back into control. Image Credit: NASA

NASA astronaut TJ Creamer talks about his experience in space during a "Tweetup" at NASA Headquarters, Thursday, July 29, 2010, in Washington. Creamer, who spent 161 days living aboard the International Space Station as part of the Expedition 22/23 crew, set up the orbiting outpost's live Internet connection and posted updates about the mission to his Twitter account, sending the first live tweet from orbit. Image Credit: NASA/Paul E. Alers

Perfectly circular, powerful Hurricane Celia spaned hundreds of miles over the Pacific Ocean in this image from June 24, 2010. Rough-textured clouds surround the storm’s distinct eye. Farther from the center of the storm, spiral arms appear thinner and smoother. The Moderate Resolution Imaging Spectroradiometer, or MODIS, on NASA’s Aqua satellite captured this true-color image of Hurricane Celia at 1:55 p.m. Pacific Daylight Time on June 24, 2010. Just five minutes later, the U.S. National Hurricane Center classified Celia as a Category 4 hurricane with sustained winds of 135 miles per hour. Image Credit: NASA

Recently, technicians at NASA's Marshall Space Flight Center in Huntsville, Ala., completed a series of cryogenic tests on six James Webb Space Telescope beryllium mirror segments at the center's X-ray & Cryogenic Facility. During testing, the mirrors were subjected to extreme temperatures dipping to -415 degrees Fahrenheit, permitting engineers to measure in extreme detail how the shape of the mirror changes as it cools. The Webb telescope has 18 mirrors, each of which will be tested twice in the Center's X-ray & Cryogenic Facility to ensure that the mirror will maintain its shape in a space environment -- once with bare polished beryllium and then again after a thin coating of gold is applied. The cryogenic test gauges how each mirror changes temperature and shape over a range of operational temperatures in space. This helps predict how well the telescope will image infrared sources. The mirrors are designed to stay cold to allow scientists to observe the infrared light they reflect using a telescope and instruments optimized to detect this light. Warm objects give off infrared light, or heat. If the Webb telescope mirror is too warm, the faint infrared light from distant galaxies may be lost in the infrared glow of the mirror itself. Thus, the Webb telescope's mirrors need to operate in a deep cold or cryogenic state, at around -379 degree Fahrenheit. Image Credit: NASA

On Jan. 2, 2004 NASA's Stardust spacecraft made a close flyby of comet Wild 2 (pronounced "Vilt-2"). Among the equipment the spacecraft carried on board was a navigation camera.that Comet Wild 2 is about 3.1 miles in diameter. This artist's concept depicts a view of Wild 2 that shows the faint jets emanating from the comet. Image Credit: NASA/JPL-Caltech

President Barack Obama greets the STS-132 Atlantis crew and International Space Station astronaut T.J. Creamer in the Oval Office, July 26, 2010. From left, STS-132 Commander Ken Ham; Expedition 22/23 Flight Engineer T.J. Creamer; STS-132 Mission Specialists Piers Sellers, Garret Reisman, and Steve Bowen; President Obama; STS-132 Mission Specialist Michael Good; and STS-132 Pilot Tony Antonelli. Official White House Photo by Pete Souza

The Orion Nebula is a 'happening' place where stars are born and this colony of hot, young stars is stirring up the cosmic scene in this image from NASA's Spitzer Space Telescope. The young stars dip and peak in brightness; shifting cold and hot spots on the stars' surfaces cause brightness levels to change. In addition, surrounding disks of lumpy planet-forming material can obstruct starlight. Spitzer is keeping tabs on the young stars, providing data on their changing ways. The hottest stars in the region are the Trapezium cluster. This image was taken after Spitzer's liquid coolant ran dry in May 2009, marking the beginning of its "warm" mission. Image Credit: NASA/JPL-Caltech

This observation from NASA's Mars Reconnaissance Orbiter shows the floor of a large impact crater in the southern highlands, north of the giant Hellas impact basin. Most of the crater floor is dark, with abundant small ripples of wind-blown material. However, a pit in the floor of the crater has exposed light-toned, fractured rock. The light-toned material appears fractured at several different scales. These fractures, called joints, result from stresses on the rock after its formation. Joints are similar to faults, but have undergone virtually no displacement. With careful analysis, joints can provide insight into the forces that have affected a rock, and thus yielding clues into its geologic history. The fractures appear dark, which may be due to dark, wind-blown sand, precipitation of different minerals along the fracture, or both. Image Credit: NASA/JPL-Caltech/University of Arizona

NASA's Swift satellite views Comet Lulin as it made it closest approach to Earth in February 2009. Lulin, like all comets, is a clump of frozen gases mixed with dust. These "dirty snowballs" cast off gas and dust whenever they venture near the sun. Comet Lulin, which is formally known as C/2007 N3, was discovered in 2008 by astronomers at Taiwan's Lulin Observatory. Lulin passed closest to Earth -- 38 million miles, or about 160 times farther than the moon -- late on the evening of Feb. 23, 2009, for North America. Image Credit: NASA, Swift, Univ. Leicester, DSS (STScI/AURUA), Dennis Bodewits, et al.

Children experience NASA from the inside during the annual "Take Your Children to Work Day" held each summer at NASA facilities across the country. Children get to see NASA facilities, participate in education activities and shadow their parents during the workday. They can also observe the agency's many different careers, learning about occupations as varied as engineering, graphic design, accounting, maintenance and many other professions. Pictured here, children explore the Exploration Experience exhibit at the Marshall Space Flight Center during a previous "Take Your Children to Work Day." The exhibit showcases NASA's accomplishments and goals, from the benefits of space exploration here on Earth, to the technologies NASA develops to explore our solar system. Image Credit: NASA/MSFC/Doug Stoffer

NASA and Manned Spacecraft Center (MSC) officials joined with flight controllers to celebrate the successful conclusion of the Apollo 11 lunar landing mission in the Mission Control Center. From left foreground Dr. Maxime A. Faget, MSC Director of Engineering and Development; George S. Trimble, MSC Deputy Director; Dr. Christopher C. Kraft Jr., MSC Director fo Flight Operations; Julian Scheer (in back), Assistant Adminstrator, Office of Public Affairs, NASA HQ.; George M. Low, Manager, Apollo Spacecraft Program, MSC; Dr. Robert R. Gilruth, MSC Director; and Charles W. Mathews, Deputy Associate Administrator, Office of Manned Space Flight, NASA HQ. Image Credit: NASA

One day homeowners everywhere may be protected from deadly carbon monoxide fumes, thanks to a device invented at NASA's Langley Research Center. The device uses a new class of low-temperature oxidation catalysts to convert carbon monoxide to non-toxic carbon dioxide at room temperature and also removes formaldehyde from the air. The catalysts initially were developed for research involving carbon dioxide lasers. Image Credit: NASA

On July 17, 1975, Cold War rivals America and the Soviet Union met in Earth orbit as American Apollo astronauts Tom Stafford, Vance Brand and Deke Slayton docked with Soviet Soyuz cosmonauts Aleksey Leonov and Valeriy Kubasov. During their joint mission, the astronauts and cosmonauts assembled this commemorative plaque in orbit as a symbol of the international cooperation. The American side is blue with English text, while the Soviet side is red with Russian text. Image Credit: NASA

An Aerojet AJ26 rocket engine was delivered to NASA's John C. Stennis Space Center on July 15, 2010. This is the first of a series of Taurus II engines to be tested at Stennis to include acceptance testing of flight engines. Stennis will provide propulsion system acceptance testing for the Taurus II space launch vehicle, which is being developed by Orbital Sciences Corporation of Dulles, Va. The first Taurus II mission will be flown in support of NASA's Commercial Orbital Transportation Services cargo demonstration to the International Space Station. Orbital's Taurus II design uses a pair of Aerojet AJ26 rocket engines to provide first stage propulsion for the new launch vehicle. Image Credit: NASA

On July 11, 2010, the new moon passed directly in front of the sun, causing a total solar eclipse in the South Pacific. In this image, the solar eclipse is shown in gray and white from a photo provided by the Williams College Expedition to Easter Island and was embedded with an image of the sun’s outer corona taken by the Large Angle Spectrometric Coronagraph (LASCO) on the SOHO spacecraft and shown in red false color. LASCO uses a disk to blot out the bright sun and the inner corona so that the faint outer corona can be monitored and studied. Further, the dark silhouette of the moon was covered with an image of the sun taken in extreme ultraviolet light at about the same time by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory. The composite brings out the correlation of structures in the inner and outer corona. Image Credit: NASA/ESA/Williams College Eclipse Expedition

Tycho's Supernova, the red circle visible in the upper left part of the image, is SN 1572 is a remnant of a star explosion is named after the astronomer Tycho Brahe, although he was not the only person to observe and record the supernova. When the supernova first appeared in November 1572, it was as bright as Venus and could be seen in the daytime. Over the next two years, the supernova dimmed until it could no longer be seen with the naked eye. In the 1950s, the remnants of the supernova could be seen again with the help of telescopes. When the star exploded, it sent out a blast wave into the surrounding material, scooping up interstellar dust and gas as it went, like a snow plow. An expanding shock wave traveled into the surroundings and a reverse shock was driven back in toward the remnants of the star. Previous observations by NASA's Spitzer Space Telescope indicate that the nature of the light that WISE sees from the supernova remnant is emission from dust heated by the shock wave. To the right is a star-forming nebula of dust and gas, called S175. This cloud of material is about 3,500 light-years away and 35 light-years across. It is heated by radiation from the young, hot stars within it, and the dust within the cloud radiates infrared light. Image Credit: NASA/JPL-Caltech/UCLA

On its way to a 2014 rendezvous with comet 67P/Churyumov-Gerasimenko, the European Space Agency's Rosetta spacecraft, with NASA instruments aboard, flew past asteroid Lutetia on Saturday, July 10. The instruments aboard Rosetta recorded the first close-up image of the biggest asteroid so far visited by a spacecraft. Rosetta made measurements to derive the mass of the object, understand the properties of the asteroid's surface crust, record the solar wind in the vicinity and look for evidence of an atmosphere. The spacecraft passed the asteroid at a minimum distance of 3,160 kilometers (1,950 miles) and at a velocity of 15 kilometers (9 miles) per second, completing the flyby in just a minute. But the cameras and other instruments had been working for hours and in some cases days beforehand, and will continue afterwards. Shortly after closest approach, Rosetta began transmitting data to Earth for processing. Lutetia has been a mystery for many years. Ground telescopes have shown that it presents confusing characteristics. In some respects it resembles a ‘C-type’ asteroid, a primitive body left over from the formation of the solar system. In others, it looks like an ‘M-type’. These have been associated with iron meteorites, are usually reddish and thought to be fragments of the cores of much larger objects. Image Credits: ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

A piece of NASA history landed at the Glenn Research Center's Visitor Center, now located at the Great Lakes Science Center in Cleveland, Ohio. The Apollo Command Module, used for the Skylab 3 mission in 1973, was moved successfully from Glenn to the Science Center on Tuesday, June 22. The module will be the focal point of the Visitor Center, which includes space and aeronautics artifacts, models and interactive experiences. The move was carefully planned to protect and preserve the module, which weighs 12,800 pounds and is more than 11 feet tall and 13 feet wide. The module is on loan from the Smithsonian’s National Air and Space Museum. Image Credit: NASA

Scientists on the sea ice in the Chukchi Sea off the north coast of Alaska disperse equipment on July 4, 2010, as they prepare to collect data on and below the ice. The research is part of NASA's ICESCAPE mission aboard the U.S. Coast Guard icebreaker Healy to sample the physical, chemical and biological characteristics of the ocean and sea ice. Impacts of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) is a multi-year NASA shipborne project. The bulk of the research will take place in the Beaufort and Chukchi Sea’s in the summer of 2010 and fall of 2011. Image Credit: NASA/Kathryn Hansen