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STS-31: Opening window to the Universe
The Hubble Space Telescope has become astronomy's crown jewel for knowledge and discovery. The great observatory was placed high above Earth following its launch aboard space shuttle Discovery on April 24, 1990. The astronauts of STS-31 recount their mission in this post-flight film presentation.

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Atlantis on the pad
Space shuttle Atlantis is delivered to Kennedy Space Center's launch pad 39B on August 2 to begin final preparations for blastoff on the STS-115 mission to resume construction of the International Space Station.

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Atlantis rollout begins
Just after 1 a.m. local time August 2, the crawler-transporter began the slow move out of the Vehicle Assembly Building carrying space shuttle Atlantis toward the launch pad.

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ISS EVA preview
Astronauts Jeff Williams and Thomas Reiter will conduct a U.S.-based spacewalk outside the International Space Station on August 3. To preview the EVA and the tasks to be accomplished during the excursion, station managers held this press conference from Johnson Space Center in Houston.

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STS-34: Galileo launch
The long voyage of exploration to Jupiter and its many moons by the Galileo spacecraft began on October 18, 1989 with launch from Kennedy Space Center aboard the space shuttle Atlantis. The crew of mission STS-34 tell the story of their flight to dispatch the probe -- fitted with an Inertial Upper Stage rocket motor -- during this post-flight presentation film.

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Atlantis on the move
Space shuttle Atlantis is transported to the cavernous Vehicle Assembly Building where the ship will be mated to the external fuel tank and twin solid rocket boosters for a late-August liftoff.

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Discovery ride along!
A camera was mounted in the front of space shuttle Discovery's flight deck looking back at the astronauts during launch. This video shows the final minutes of the countdown and the ride to space with the live launch audio included. The movie shows what it would be like to launch on the shuttle with the STS-121 crew.

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Shuttle from the air
A high-altitude WB-57 aircraft flying north of Discovery's launch trajectory captures this incredible aerial footage of the space shuttle's ascent from liftoff through solid rocket booster separation.

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Launch experience
This is the full launch experience! The movie begins with the final readiness polls of the launch team. Countdown clocks then resume ticking from the T-minus 9 minute mark, smoothly proceeding to ignition at 2:38 p.m. Discovery rockets into orbit, as seen by ground tracker and a video camera mounted on the external tank. About 9 minutes after liftoff, the engines shut down and the tank is jettisoned as the shuttle arrives in space.

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Delta 2 launches MiTEx
MiTEx -- an experimental U.S. military project to test whether the advanced technologies embedded in two miniature satellites and a new upper stage kick motor can operate through the rigors of spaceflight -- is launched from Cape Canaveral aboard a Boeing Delta 2 rocket.

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Hubble images some of galaxy's dimmest stars
RICE UNIVERSITY NEWS RELEASE
Posted: August 17, 2006

Using the Hubble Space Telescope, astronomers have imaged some of the galaxy's oldest and dimmest stars, offering a rare experimental glimpse of two mysterious star types tiny, slow burners less than one-tenth the size of our sun and once giant stars that still glow more than 10 billion years after their deaths.


Looking like glittering jewels, the stars in this Hubble Space Telescope image at left are part of the ancient globular star cluster NGC 6397. The image at lower right shows the faintest red dwarf star (the red dot within the red circle) spied by Hubble. The image at upper right pinpoints one of the dim white dwarfs (the blue dot within the blue circle) seen by Hubble. Credit: NASA, ESA, and H. Richer (University of British Columbia)
 
The research appears in this week's issue of the journal Science.

"This project pushed the limits of what even Hubble can do," said study co-author Jay Anderson, a research scientist at Rice University. "These stars can't be reliably detected in a single image. You have to combine a large number of images to find them."

In total, the research team trained Hubble's cameras on the same patch of sky for more than 75 hours, gathering 378 overlapping images. The target was a region of space containing about 1 percent of the globular cluster NGC 6397 a collection of stars that formed early in our galaxy's history.

"When we look at random stars in the sky they have a variety of ages," Anderson said. "Globular clusters offer unique opportunities for astronomers to study a population of stars that are all the same age. All the stars we see in clusters are ancient, because they were created when the galaxy was forming. They're fossils from the galaxy's earliest days."

There are about 150 globular clusters in our galaxy, and most contain between 100,000 and 1 million stars. While most of the galaxy's stars including our own sun orbit the galactic center in the plane of the galaxy, globular clusters predate the flattening of the Milky Way, so they're scattered in a more spherical distribution.

NGC 6397 is one of the nearest clusters to Earth, located just 8,500 light years away. But even at this relatively close astronomical distance, the light from NGC 6397's faintest stars is easily lost in the glare from its brightest stars.

To survey the dimmest objects, Anderson and colleagues relied on computers. Anderson, whose specialty is writing programs to sift through astronomical data, spent months writing and refining software that could examine each Hubble image, pixel by pixel, and find the faintest stars.

The two types of object imaged represent the heavy end and the light end of the stellar mass spectrum.

A star's destiny is determined by its mass. There's a minimum mass that a star must have in order to burn hydrogen, and objects below that threshold cool rapidly and fade away. From the NGC 6397 survey, Anderson and his colleagues identified the smallest visible stars yet seen in a globular cluster, stars less than one-tenth the mass of Earth's sun. This is very near the predicted theoretical threshold, and Anderson said data from the survey will be helpful for verifying and refining theories about the structure and evolution of low-mass stars.

On the other end of the stellar mass spectrum are stars that are significantly larger than the sun. Stars about eight times the mass of the sun burn quickly and die in spectacular planetary nebulae, explosions that spew much of the star's material into space. Upon their final collapse, these stars become white dwarfs, extremely dense objects that radiate heat for billions of years as they slowly fade into darkness. Anderson said that while the brightest and therefore youngest white dwarfs have been seen in many clusters, the new survey yielded the first images of the faintest and oldest white dwarfs in an ancient cluster. The brightness of the white dwarfs at this end of the scale can help astronomers find out how long the stars have been cooling. From that, they can better determine the age of the cluster, which in turn can be used to narrow estimates of the lower limit of the age of the universe.

Co-authors on the study include principal investigator Harvey Richer, James Brewer, Saul Davis and Peter Stetson, all of the University of British Columbia; Gregory Fahlman of the Herzberg Institute of Astrophysics in Victoria, British Columbia; Brad Hansen, David Reitzel and Michael Rich, all of the University of California Los Angeles; Jarrod Hurley of Australia's Monash University; Jasonjot Kalirai of the University of California Santa Cruz; Ivan King of the University of Washington; and Michael Shara of the American Museum of Natural History.

The research was funded by the Natural Sciences and Engineering Research Council of Canada, the University British Columbia, NASA and the Space Telescope Science Institute.