On May 29, 1953, Edmund Hillary, from New Zealand, and Tenzing Norgay, from Nepal, became the first humans to successfully climb to the peak of Mt. Everest, the tallest mountain in the world. They were part of a British expedition lead by Colonel John Hunt sent specifically to reach what was regarded at the time as the 'third pole.' In decades prior, major British expeditions had attempted to be the first to reach the North and South Poles only to come in second place behind the Americans (Robert Peary's expedition to the North Pole) and the Norwegians (Roald Amundsen's expedition to the South Pole). The British made seven attempts to scale Mt. Everest in the previous decades, usually on the North Face from Tibet. But following the Chinese Revolution in 1949, this route to the mountain was closed and so Mt. Everest expeditions had to explore new routes to reach the peak.

The 1953 British Expedition climbed up onto the South Col and then along the Southeast Ridge by a route, which is now the most heavily used by the thousands of climbers who have attempted to climb the mountain since. At the time, there were some doubts whether this approach was possible. At 29,035 feet (8,848 m) in altitude, the air is only one-third as thick as the air at sea level. Members of the expedition, as they did in previous attempts, carried bottled oxygen, but this made for a very heavy load on the climbers and could only supplement their oxygen needs, not fully meet them.

Since 1953, many successful expeditions have climbed Mt. Everest, including the first American expedition in 1963. However, most climbers fail to make the peak, and many people die each year in the attempt. As of 2003 when this Landsat 7 image was taken, more than 5,000 people have attempted to repeat their feat with only 1,600 successes and 175 fatalities.

The All-American Canal, the largest irrigation canal in the world and a key landmark along the U.S.-Mexico border, is the focus of this image, taken by the crew of Expedition 18 aboard the International Space Station. The prominent dark line crossing the image is the canal, which is crossed in this view by Interstate Highway 8. The canal carries 26,155 cubic feet of water per second westward from the Colorado River to support the intensive agriculture of California's Imperial Valley to the northwest and nine cities, including San Diego. The canal system is the Imperial Valley's only source of water, and it allows irrigation of more than 500,000 acres of agricultural fields. The Coachella Canal, one of four main branch canals, leads water north to Imperial Valley.

This Landsat 7 image of Guinea-Bissau, a small country in West Africa, shows the complex patterns of the country's shallow coastal waters, where silt carried by the Geba and other rivers washes out into the Atlantic Ocean.

Aracar volcano is one of many volcanoes in the Andes Range that is located just east of the Argentina-Chile border. Well-preserved lava flows are found at its base. Prior to a report of ash columns from the summit in 1993, the volcano was not known to be active and very little is known of the volcano's age and history.

Salars, the large whitish features are very common in the arid Andes. The term salar is used exclusively of the saltwater wetlands of the Puna (high Andes) and can describe not only salt lakes but also temporary marshes, shallow lakes and lagoons, or simply salt crust. The nearby Salar del Hombre Muerto is being put into mineral production. The endeavor is expected to become one of Argentina's biggest mines, producing up to 20,000 tons of lithium carbonate and lithium chloride per year, to be extracted by pumping from the area's lithium-rich saltbeds.

This image was taken from the space shuttle on Feb. 20, 2000.

The Apollo 16 crew captured this Earthrise with a handheld Hasselblad camera during the second revolution of the moon. Identifiable craters seen on the moon include Saha, Wyld and Saenger. Much of the terrain seen here is never visible from the Earth, as the command module was passing onto what is known as the 'dark side' of the moon.

Apollo 16 launched on April 16, 1972 and landed on the moon on April 20. The mission was commanded by John Young; Thomas K. Mattingly II was the command module pilot and Charles M. Duke, Jr. served as the lunar module pilot.

The most crowded collision of galaxy clusters has been identified by combining information from three different telescopes. This result gives scientists a chance to learn what happens when some of the largest objects in the universe go at each other in a cosmic free-for-all.

Using data from NASA's Chandra X-ray Observatory, Hubble Space Telescope and the Keck Observatory on Mauna Kea, Hawaii, astronomers were able to determine the three-dimensional geometry and motion in the system MACSJ0717.5+3745 (or MACSJ0717 for short) located about 5.4 billion light years from Earth.

The researchers found that four separate galaxy clusters are involved in a triple merger, the first time such a phenomenon has been documented. Galaxy clusters are the largest objects bound by gravity in the universe.

In MACSJ0717, a 13-million-light-year-long stream of galaxies, gas and dark matter -- known as a filament -- is pouring into a region already full of galaxies. Like a freeway of cars emptying into a full parking lot, this flow of galaxies has caused one collision after another.

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this 180-degree view of the rover's surroundings during the 1,823rd Martian day, or sol, of Spirit's surface mission (Feb. 17, 2009). The center of the view is toward the south-southwest.

The rover had driven 23 feet, or 7 meters, eastward earlier on Sol 1823, part of maneuvering to get Spirit into a favorable position for climbing onto the low plateau called 'Home Plate.' However, after two driving attempts with negligible progress during the following three sols, the rover team changed its strategy for getting to destinations south of Home Plate. The team decided to drive Spirit at least partway around Home Plate, instead of ascending the northern edge and taking a shorter route across the top of the plateau.

The parachute for NASA's Mars Science Laboratory (MSL) passed flight-qualification after testing in March and April 2009 inside the world's largest wind tunnel at NASA's Ames Research Center.

In this image, an engineer is dwarfed by the parachute, the largest ever built to fly on an extraterrestrial flight. It is designed to survive deployment at Mach 2.2 in the Martian atmosphere, where it will generate up to 65,000 lb of drag force.

The parachute, built by Pioneer Aerospace, has 80 suspension lines, measures more than 165 feet in length, and opens to a diameter of nearly 51 feet. The wind tunnel itself is 80 feet tall and 120 feet wide -- large enough to house a Boeing 737.

JPL is building and testing the MSL spacecraft, which is slated to launch in 2011. The mission will land a roving analytical laboratory on the surface of Mars in 2012.

Nearly 30 years ago this week, a new era in space flight began, when on April 12, 1981 the first shuttle mission was launched. STS-1 commander John Young had already flown in space four times, including a walk on the moon in 1972. Bob Crippen, the pilot, was a Navy test pilot who would go on to command three future shuttle missions.

President Richard M. Nixon and the Apollo 13 crew salute U.S. flag during the post-mission ceremonies at Hickam Air Force Base, Hawaii. Earlier, the astronauts John Swigert, Jim Lovell and Fred W. Haise were presented the Presidential Medal of Freedom by the Chief Executive.

Apollo 13, launched on April 11, 1970, was NASA's third manned mission to the moon. Two day later on April 13 while the mission was en route to the moon, a fault in the electrical system of one of the Service Module's oxygen tanks produced an explosion that caused both oxygen tanks to fail and also led to a loss of electrical power. The command module remained functional on its own batteries and oxygen tank, but these were usable only during the last hours of the mission. The crew shut down the Command Module and used the Lunar Module as a "lifeboat" during the return trip to earth. Despite great hardship caused by limited power, loss of cabin heat, and a shortage of potable water, the crew returned to Earth, and the mission was termed a "successful failure."

Technicians were performing pre-launch testing of the Mercury-Atlas 9 (MA9) on Launch Pad 14 at Cape Canaveral when this photo was taken on May 14, 1963. A day later on May 15, Gordon Cooper successfully piloted this his 'Faith 7' spacecraft for more than 34 hours and 22 orbits.

Cooper's flight stretched the capabilities of the Mercury capsule to the limits. His 34-hour flight lasted more than three times the longest U.S. human space flight until that time, and far exceeded the initial design capability of the capsule.

Less than a year after its birth, the National Aeronautics and Space Agency announced its first astronaut class, the Mercury Seven, on April 9, 1959. Project Mercury proved that humans could live and work in space, paving the way for all future human exploration.

This cutaway drawing of the Mercury capsule was used by the Space Task Group at the first NASA inspection, on Oct. 24, 1959.

The Soyuz TMA-13 spacecraft, carrying Expedition 18 Commander Michael Fincke, Flight Engineer Yury V. Lonchakov and American Spaceflight Participant Charles Simonyi, lands, Wednesday, April 8, 2009, near Zhezkazgan, Kazakhstan. Fincke and Lonchakov return after spending six months on the International Space Station, and Simonyi is returning from his launch with the Expedition 19 crew members 12 days earlier.

A small, dense object only 12 miles in diameter is responsible for this beautiful X-ray nebula that spans 150 light years. At the center of this image made by NASA's Chandra X-ray Observatory is a very young and powerful pulsar, known as PSR B1509-58, or B1509 for short. The pulsar is a rapidly spinning neutron star which is spewing energy out into the space around it to create complex and intriguing structures, including one that resembles a large cosmic hand.

In this image, the lowest energy X-rays that Chandra detects are red, the medium range is green, and the most energetic ones are colored blue. Astronomers think that B1509 is about 1,700 years old and it is located about 17,000 light years away.

Neutron stars are created when massive stars run out of fuel and collapse. B1509 is spinning completely around almost 7 times every second and is releasing energy into its environment at a prodigious rate -- presumably because it has an intense magnetic field at its surface, estimated to be 15 trillion times stronger than the Earth's magnetic field.

The combination of rapid rotation and ultra-strong magnetic field makes B1509 one of the most powerful electromagnetic generators in the galaxy. This generator drives an energetic wind of electrons and ions away from the neutron star. As the electrons move through the magnetized nebula, they radiate away their energy and create the elaborate nebula seen by Chandra.

On April 1-2, the Hubble Space Telescope photographed the winning target in the Space Telescope Science Institute’s 'You Decide' competition in celebration of the International Year of Astronomy (IYA).

The winner is a group of galaxies called Arp 274. The striking object received 67,021 votes out of the nearly 140,000 votes cast for the six candidate targets.

Arp 274, also known as NGC 5679, is a system of three galaxies that appear to be partially overlapping in the image, although they may be at somewhat different distances. The spiral shapes of two of these galaxies appear mostly intact. The third galaxy (to the far left) is more compact, but shows evidence of star formation.

Two of the three galaxies are forming new stars at a high rate. This is evident in the bright blue knots of star formation that are strung along the arms of the galaxy on the right and along the small galaxy on the left.

The largest component is located in the middle of the three. It appears as a spiral galaxy, which may be barred. The entire system resides at about 400 million light-years away from Earth in the constellation Virgo.

Hubble's Wide Field Planetary Camera 2 was used to image Arp 274. Blue, visible and infrared filters were combined with a filter that isolates hydrogen emission. The colors in this image reflect the intrinsic color of the different stellar populations that make up the galaxies. Yellowish older stars can be seen in the central bulge of each galaxy. A bright central cluster of stars pinpoint each nucleus. Younger blue stars trace the spiral arms, along with pinkish nebulae that are illuminated by new star formation. Interstellar dust is silhouetted against the starry population. A pair of foreground stars inside our own Milky Way are at far right.

The International Year of Astronomy is the celebration of the 400th anniversary of Galileo's first observations with a telescope. People around the world came together to participate in the IYA's 100 Hours of Astronomy, April 2 to 5. This global astronomy event was geared toward encouraging as many people as possible to experience the night sky.

The Soyuz TMA-14 launches from the Baikonur Cosmodrome in Kazakhstan on Thursday, March 26, 2009, carrying Expedition 19 Commander Gennady I. Padalka, Flight Engineer Michael R. Barratt and spaceflight participant Charles Simonyi to the International Space Station.

Spectators gather around a mock-up of the Orion capsule that will carry astronauts back to the moon. The capsule is being displayed on the National Mall in Washington, D.C.

Scheduled to make its first flights to the International Space Station early in the next decade, Orion is part of the Constellation Program to send human explorers back to the moon, and then onward to Mars and other destinations in the solar system.

The boosters of the Soyuz rocket that transported Expedition 19 to the space station are shown here as the Soyuz TMA-14 spacecraft and boosters are assembled on March 23, 2009, at the Baikonur Cosmodrome in Kazakhstan. The Soyuz successfully launched on March 26, carrying Expedition 19 Commander Gennady Padalka and Flight Engineer Mike Barratt, as well as a U.S. spaceflight participant.

In 19 years of observations, the Hubble Space Telescope has amassed a huge archive of data--an archive that may contain the telltale glow of undiscovered extrasolar planets. Such is the case with HR 8799b, shown in this artist's concept. The planet is one of three extrasolar planets orbiting the young star HR 8799, which lies 130 light-years away.

The planetary trio was originally discovered in images taken with the Keck and Gemini North telescopes in 2007 and 2008. But using a new image processing technique that suppresses the glare of the parent star, scientists found the telltale glow of the outermost planet in the system while studying Hubble archival data taken in 1998.

The giant planet is young and hot, but still only 1/100,000th the brightness of its parent star. By comparison, Jupiter is one-billionth the brightness of our sun.

Technicians from Ball Aerospace inspected the honeycomb structure of the Kepler Space Telescope's primary mirror. The mirror has been 86% light-weighted; that is, it only weighs 14% of amount that a solid mirror of the same dimensions would. The mirror blank was made by Corning Glass works out of ultra-low expansion glass, or ULE. The optical polishing of the mirror was performed by Brashear LP.

Kepler launched On March 7, 2009, on a 3 1/2 year mission to survey the more than 100,000 sun-like stars in the Cygnus-Lyra region of our Milky Way galaxy. It is expected to find hundreds of planets the size of Earth and larger at various distances from their stars.

There is now clear evidence for substantial numbers of three types of exoplanets; gas giants, hot-super-Earths in short period orbits, and ice giants. The challenge is to find terrestrial planets, especially those in the habitable zone of their stars where liquid water might exist on the surface of the planet.