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Launch of New Horizons
The New Horizons spacecraft begins a voyage across the solar system to explore Pluto and beyond with its successful launch January 19 aboard a Lockheed Martin Atlas 5 rocket from Cape Canaveral, Florida.

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Stardust comes home
NASA's Stardust spacecraft returns samples of cometary dust to Earth with its safe landing in Utah on January 15.

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NASA administrator
NASA Administrator Mike Griffin and his deputy Shana Dale hold a news conference at Kennedy Space Center in the final hours of the countdown to the New Horizons launch. Questions from reporters ranged from the Pluto-bound mission, the agency's budget and the space shuttle program.

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STS-32: LDEF retrieval
Space shuttle Columbia's mission in January 1990 sought to retrieve the Long Duration Exposure Facility -- a bus-size platform loaded with 57 experiments -- that had been put into orbit six years earlier. LDEF was supposed to be picked up within a year of its launch. But plans changed and then the Challenger accident occurred. Columbia's STS-32 crew got into space, deployed a Navy communications satellite, then fulfilled their LDEF recovery mission, carried out a host of medical tests and returned to Earth with a nighttime touchdown in the California desert. The crew presents this post-flight film of mission highlights.

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NASA through the decades
This film looks at the highlights in NASA's history from its creation in the 1950s, through the glory days of the Mercury, Gemini and Apollo programs, birth of the space shuttle and the loss of Challenger, launch of Hubble and much more.

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STS-49: Satellite rescue
If at first you don't succeed, keep on trying. That is what the astronauts of space shuttle Endeavour's maiden voyage did in their difficult job of rescuing a wayward communications satellite. Spacewalkers were unable to retrieve the Intelsat 603 spacecraft, which had been stranded in a useless orbit, during multiple attempts using a special capture bar. So the crew changed course and staged the first-ever three-man spacewalk to grab the satellite by hand. The STS-49 astronauts describe the mission and narrate highlights in this post-flight presentation.

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First satellite repair
The mission for the crew of space shuttle Challenger's April 1984 flight was two-fold -- deploy the experiment-laden Long Duration Exposure Facility (LDEF) and then track down the crippled Solar Max spacecraft, capture it and perform repairs during spacewalks. Initial attempts by the astronauts to grab the craft while wearing the Manned Maneuvering Unit spacewalk backpacks failed, but the crew ultimately retrieved Solar Max and installed fresh equipment while it was anchored in the payload bay. The crew narrates this post-flight presentation of home movies and highlights from mission STS-41C.

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STS-26: Back in space
The space shuttle program was grounded for 32 months in the painful wake of the 1986 Challenger accident. Americans finally returned to space in September 1988 when shuttle Discovery safely launched for its mission to deploy a NASA communications satellite. Enjoy this post-flight presentation narrated by the astronauts as they show movies and tell the story of the STS-26 mission.

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Amazing STS-51I flight
Imagine a space shuttle mission in which the astronaut crew launched two commercial and one military communications spacecraft, then conducted a pair of incredible spacewalks to recover, fix and redeploy a satellite that malfunctioned just four months earlier. The rescue mission was a success, starting with an astronaut making a catch of the spinning satellite with just his gloved-hand. Enjoy this post-flight presentation narrated by the astronauts as they tell the story of shuttle Discovery's August 1985 mission known as STS-51I.

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Astronomers find smallest extrasolar planet yet
Posted: January 25, 2006

This artist's illustration shows an icy/rocky planet orbiting a dim star. Astronomers detected an extrasolar planet five times as massive as Earth circling a red dwarf, a relatively cool star. The distance between the planet, designated OGLE-2005-BLG-390Lb, and its host is about three times greater than that between the Earth and the Sun. The planet's large orbit and its dim parent star make its likely surface temperature a frigid minus 364 degrees Fahrenheit (minus 220 degrees Celsius). Credit: NASA, ESA and G. Bacon (STScI)
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Using a relatively new planet-hunting technique that can spot worlds one-tenth the mass of our own, researchers have discovered a potentially rocky, icy body that may be the smallest planet yet found orbiting a star outside our solar system.

The discovery suggests the technique, gravitational microlensing, may be an exceptional technology for finding distant planets with traits that could support life.

"This is an important breakthrough in the quest to answer the question 'Are we alone?'" said Michael Turner, assistant director for the National Science Foundation (NSF) mathematical and physical sciences directorate. "The team has discovered the most Earth-like planet yet, and more importantly, has demonstrated the power of a new technique that is sensitive to detecting habitable planets. It can probe a much greater portion of our galaxy and is complementary to other techniques."

Located more than 20,000 light years away in the constellation Sagittarius, close to the center of our Milky Way galaxy, planet OGLE-2005-BLG-390Lb is approximately five-and-a-half times the mass of Earth.

Orbiting a star one-fifth the mass of the sun at a distance almost three times that of Earth's orbit, the newly discovered planet is frigid: the estimated surface temperature is -364 degrees Fahrenheit (-220 degrees Celsius).

Although astronomers doubt this cold body could sustain organisms, researchers believe gravitational microlensing will bring opportunities for observing other rocky planets in the "habitable zones" of stars - regions where temperatures are perfect for maintaining liquid water and spawning life.

The discovery, authored by 73 collaborators from 32 institutions, appears in the Jan. 26 issue of the journal Nature.

OGLE (Optical Gravitational Lensing Experiment) project telescopes first observed the lensing event on July 11, 2005. In an attempt to catch microlensing events as they occur, OGLE scans most of the central Milky Way each night, discovering more than 500 microlensing events per year. But to detect the signature of low-mass planets, astronomers must observe these events much more frequently than OGLE's one survey per night.

So, when OGLE detected the July 11 lensing, its early warning system alerted fellow astronomers across the globe to microlensing event OGLE-2005-BLG-390 (for the 390th galactic bulge OGLE discovered in 2005). At that point, though, no one knew a planet would emerge.

"The only way to realize the full scientific benefit of our observations is to share the data with our competition," said co-author Bohdan Paczynski of Princeton University, who along with Andrzej Udalski of Warsaw University Observatory and their colleagues co-founded OGLE in 1997.

The telescopes of PLANET (Probing Lensing Anomalies NETwork) and RoboNet tracked the July 11 episode to completion, providing the data that confirmed the presence of a previously unknown planet. These telescopes collect observations more frequently in an attempt to detect the microlensing signature of planets.

"This discovery was possible because the sun never rises on the PLANET collaboration," said lead author and PLANET researcher Jean-Philippe Beaulieu of the Institut d'Astrophysique de Paris, France. "The global nature of the PLANET collaboration was crucial for obtaining data throughout the 24-hour planetary signal," he added.

Ironically, when preparing the final report, the researchers discovered that during its test runs, the new MOA (Microlensing Observations in Astrophysics) telescope, MOA-2, had taken additional measurements of the lensing event. The 6-foot (1.8-meter) aperture telescope has a wider field-of-view than the OGLE telescope, enabling it to observe 100 million stars many times per night. MOA-2 is one of several recent and future advancements that gravitational microlensing proponents hope will greatly increase the number of Earth-like planet discoveries.

OGLE also has plans to increase the field-of-view of its own telescope, and other microlensing groups are proposing to build a new telescope in South Africa. They have also proposed a space mission to see planets as small as Mars as well as free-floating planets that no longer orbit a host star.

"The new discovery provides a strong hint that low-mass planets may be much more common than Jupiters," said co-author and PLANET researcher David Bennett of the University of Notre Dame. Most extrasolar planets found so far have been Jupiter-sized.

"Microlensing should have discovered dozens of Jupiters by now if they were as common as these five-Earth-mass planets. This illustrates the primary strength of the gravitational microlensing method: its ability to find planets of low-mass," Bennett said.

Low-mass planets can yield signals that are too weak to detect with other methods. With microlensing, the signals of low-mass planets are rare but not weak. Thus, the rate of low-mass planet discoveries should increase dramatically if more microlensing events can be searched for planetary signals.

What is Microlensing?

The gravitational microlensing technique is based on a concept first discussed by Albert Einstein in the early 20th century. When astronomers observe a star, the light waves generally travel straight from the star to the telescope. However, if another star passes directly in between, even if great distances separate the two, the gravity of the nearer object acts like a lens and magnifies the incoming light.

Telescopes cannot resolve the details of the magnified image, but they do notice a peak in light intensity, and when a planet is present around the closer star, the planet's gravity adds a small peak of its own.

Astronomers can use those features to determine how large the planet is and how far away it is from its star. This method is 50 times more likely to detect planets of approximately twice the mass of Jupiter than it is to detect planets closer to the mass of Earth. Even relatively tiny, low-mass objects can give a strong peak signal if alignment is perfect.

Of the more than 150 planets discovered to date, almost all were discovered using a different technique, the radial velocity method. Stars with planets can wobble from the effect of their planets' gravity, and astronomers can use the wobble to determine the size and orbit of the objects. While incredibly effective, existing technology utilizing this method can find only large, Jupiter-like planets or smaller planets that orbit too close to their host stars to harbor life.

Because the newly discovered planet is only the third astronomers have detected using gravitational microlensing and already they have found a small, rocky body, the researchers believe there is a strong likelihood that rocky planets may be even more common than their gas-giant brethren. This prediction would agree with one of the models for solar system formation, core accretion, which suggests that small, rocky, "failed Jupiters" should be far more common than the massive gaseous planets.



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