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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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   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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Astronaut breakfast
Dressed in festive Hawaiian shirts, Discovery's seven astronauts are gathered around the dining room table in crew quarters for breakfast. They were awakened at 6:05 a.m. EDT to begin the launch day dress rehearsal at Kennedy Space Center. (1min 57sec file)
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Solar fireworks signal new space weather mystery
NASA NEWS RELEASE
Posted: May 27, 2005

The most intense burst of solar radiation in five decades accompanied a large solar flare on January 20. It shook space weather theory and highlighted the need for new forecasting techniques, according to several presentations at the American Geophysical Union (AGU) meeting this week in New Orleans.


An artist's concept shows a solar flare erupting. Credit: NASA/Walt Feimer
 
The solar flare, which occurred at 2 a.m. EST, tripped radiation monitors all over the planet and scrambled detectors on spacecraft. The shower of energetic protons came minutes after the first sign of the flare. This flare was an extreme example of the type of radiation storm that arrives too quickly to warn interplanetary astronauts.

"This flare produced the largest solar radiation signal on the ground in nearly 50 years," said Dr. Richard Mewaldt of the California Institute of Technology, Pasadena, Calif. He is a co-investigator on NASA's Advanced Composition Explorer (ACE) spacecraft. "But we were really surprised when we saw how fast the particles reached their peak intensity and arrived at Earth."

Normally it takes two or more hours for a dangerous proton shower to reach maximum intensity at Earth after a solar flare. The particles from the January 20 flare peaked about 15 minutes after the first sign.

"That's important because it's too fast to respond with much warning to astronauts or spacecraft that might be outside Earth's protective magnetosphere," Mewaldt said. "In addition to monitoring the sun, we need to develop the ability to predict flares in advance if we are going to send humans to explore our solar system."

The event shakes the theory about the origin of proton storms at Earth. "Since about 1990, we've believed proton storms at Earth are caused by shock waves in the inner solar system as coronal mass ejections plow through interplanetary space," said Professor Robert Lin of the University of California at Berkeley. He is principal investigator for the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). "But the protons from this event may have come from the sun itself, which is very confusing."

The origin of the protons is imprinted in their energy spectrum, as measured by ACE and other spacecraft, which matches the energy spectrum of gamma-rays thrown off by the flare, as measured by RHESSI. "This is surprising because in the past we believed the protons making gamma-rays at the flare were produced locally and the ones at the Earth were produced instead by shock acceleration in interplanetary space," Lin said. "The similarity of the spectra suggests they are the same."

Solar flares and coronal mass ejections (CMEs), associated giant clouds of plasma in space, are the largest explosions in the solar system. They are caused by the buildup and sudden release of magnetic stress in the solar atmosphere above the giant magnetic poles we see as sunspots. The Transitional Region and Coronal Explorer (TRACE) and the Solar and Heliospheric Observatory (SOHO) spacecraft are devoted to observing the sun and identifying the root causes of flares and CMEs, with an eye toward forecasting them.

"We do not know how to predict the flow of energy into and through these large flares", said Dr. Richard Nightingale of the Lockheed Martin Solar and Astrophysics Laboratory in Palo Alta, Calif. "Instruments like TRACE give us new clues with each event we observe."

TRACE has identified a possible source of the magnetic stress that causes solar flares. The sunspots that give off the very largest (X-class) flares appear to rotate in the days around the flare. "This rotation stretches and twists the magnetic field lines over the sunspots", Nightingale said. "We have seen it before virtually every X-flare that TRACE has observed since it was launched and more than half of all flares in that time."

However, rotating sunspots are not the whole story. The unique flare came at the end of a string of five other very large flares from the same sunspot group, and no one knows why this one produced more sudden high energy particles than the first four.

"It means we really don't understand how the sun works," Lin said. "We need to continue to operate and exploit our fleet of solar-observing spacecraft to identify how it works."