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Discovery in the VAB
Shuttle Discovery enters into the Vehicle Assembly Building after a 10-hour journey from launch pad 39B. (4min 29sec file)
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Memorial Day message
The International Space Station's Expedition 11 crew pays tribute to our fallen heroes for Memorial Day. (1min 00sec QuickTime file)
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Apollo-era transporter
In the predawn hours, the Apollo-era crawler-transporter is driven beneath shuttle Discovery's mobile launch platform at pad 39B in preparation for the rollback to the Vehicle Assembly Building. (2min 37sec QuickTime file)
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Unplugging the shuttle
Workers disconnect a vast number of umbilicals running between launch pad 39B and Discovery's mobile launch platform for the rollback. The cabling route electrical power, data and communications to the shuttle. (2min 32sec file)
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Shuttle rollback
The crawler-transporter begins rolling space shuttle Discovery off launch pad 39B at 6:44 a.m. EDT May 26 for the 4.2-mile trip back to the Vehicle Assembly Building. (7min 28sec file)
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Voyager adventures
This animation shows the Voyager spacecraft heading into the solar system's final frontier and the edge of interstellar space. (1min 24sec file)
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Mike Griffin at KSC
NASA Administrator Mike Griffin and Kennedy Space Center Director Jim Kennedy chat with reporters at the Cape on a wide range of topics. The press event was held during Griffin's tour of the spaceport. (27min 48sec file)
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Delta rocket blasts off
The NOAA-N weather satellite is launched aboard a Boeing Delta 2 rocket from Vandenberg Air Force Base, California.

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   Liftoff | Extended clip
   Umbilicals | IR tracker

NOAA pre-launch
Officials from NASA, NOAA, the Air Force and Boeing hold the pre-launch news conference at Vandenberg Air Force Base to preview the mission of a Delta 2 rocket and the NOAA-N weather satellite. (29min 54sec file)

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Countdown culmination
Watch shuttle Discovery's countdown dress rehearsal that ends with a simulated main engine shutdown and post-abort safing practice. (13min 19sec file)
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Going to the pad
The five-man, two-woman astronaut crew departs the Operations and Checkout Building to board the AstroVan for the ride to launch pad 39B during the Terminal Countdown Demonstration Test countdown dress rehearsal. (3min 07sec file)
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Suiting up
After breakfast, the astronauts don their launch and entry partial pressure suits before heading to the pad. (3min 14sec file)
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Scientists confirm liquid water on early Earth
Posted: June 3, 2005

Research funded partly by NASA has confirmed the existence of liquid water on the Earth's surface more than 4 billion years ago.

Scientists have found that the Earth had formed patterns of crust formation, erosion and sediment recycling as early as 4.35 billion years ago. Their findings came during a study of zircon crystals formed during the earliest period of Earth's history, the Hadean Eon (4.5 billion to 4.0 billion years ago).

"NASA is interested in how early the Earth had abundant liquid water. If oceans form early in a planet's history, then so can life," said Carl Pilcher, senior scientist for astrobiology at NASA Headquarters, Washington. "Learning how early oceans formed on Earth will help us understand where else oceans and perhaps even life may have formed in this solar system and in planetary systems around other stars."

"This work provides direct evidence that the Earth was probably habitable within a hundred million years of its formation," said Bruce Runnegar, director of the NASA Astrobiology Institute (NAI) at NASA Ames Research Center, Moffett Field, Calif., which provided some of the study's funding.

Published in Science, the research was conducted by T. Mark Harrison of the Research School of Earth Sciences, Australian National University, Canberra and the University of California, Los Angeles; and E. Bruce Watson of the Department of Earth & Environmental Sciences at Rensselaer Polytechnic Institute, Troy, N.Y. Field research was completed in Western Australia's Jack Hills, which preserve a record of the Hadean Eon.

Watson and Harrison devised a new method of determining the temperatures at which the rocks formed. The team extracted and examined more than 50,000 zircons, crystals about the width of a human hair, which have been exposed through natural erosion in the Jack Hills. From the 50,000 zircons, only a couple of hundred were older than 4.2 billion years. Measuring the temperature at which the rocks melt gives an indication of the conditions in which they formed.

"Rocks formed as a result of the thermal energy from meteorite impacts would be bone dry and melt at greater than 900 degrees Celsius," said Harrison. "In contrast, our study has found that Hadean rocks melted at a consistent average temperature of 690 degrees Celsius. Water, which is a very powerful catalyst, must have been present in very large amounts for rocks to melt at such a relatively low temperature."

This discovery supports the proposal by Harrison's group four years earlier that a heavy oxygen isotope signature in the Hadean zircons is evidence for liquid water at or near the Earth's surface by 4.3 billion years ago.

The NAI, founded in 1997, is a partnership between NASA, 16 major U.S. teams and five international consortia. NAI's goal is to promote, conduct and lead integrated multidisciplinary astrobiology research and to train a new generation of astrobiology researchers.