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Crew remembers Reagan
The two-man crew living aboard the International Space Station pays tribute to President Ronald Reagan. (2min 20sec file)
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Rover enters crater
Ride along with Oppportunity as the rover drives into and back out of Endurance Crater on June 8.
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Tuesday's Mars briefing
Plans to drive the Mars rover Opportunity into Endurance Crater and new results from Spirit's search for past water at Gusev Crater are announced at this briefing from June 8. (38min 18sec file)
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Drive path
Opportunity's path into Endurance Crater and plans for the drive are explained by mission manager Jim Erickson. (1min 28sec file)
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Crater science
The rover lead scientist, Steve Squyres, explains what Opportunity will study inside Endurance Crater and what the results would say about Mars. (3min 09sec file)
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Columbia Hills
Steve Squyres, rover principal investigator, narrates a new panorama from Spirit showing the Columbia Hills. (2min 01sec file)
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Jupiter's moon Io is hottest body outside the sun
WASHINGTON UNIVERSITY NEWS RELEASE
Posted: June 11, 2004

The hottest spot in the solar system is neither Mercury, Venus, nor St. Louis in the summer. Io, one of the four satellites that the Italian astronomer Galileo discovered orbiting Jupiter almost 400 years ago, takes that prize. The Voyager spacecraft discovered volcanic activity on Io over 20 years ago and subsequent observations show that Io is the most volcanically active body in the solar system. The Galileo spacecraft, named in honor of the astronomer Galileo, found volcanic hot spots with temperatures as high as 2,910 Fahrenheit (1,610 Celsius).

Now computer models of volcanic eruptions on Io performed by researchers at Washington University in St. Louis show that the lavas are so hot that they are vaporizing sodium, potassium, silicon and iron and probably other gases as well into its atmosphere.

Using an updated version of MAGMA, a versatile computer program he developed 15 years ago with a Harvard University colleague, Bruce Fegley, Jr., Ph.D., professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, found that some of these elements are vaporized at least partly as single-atom gases. Others are vaporized in different molecular forms, for instance, silicon monoxide, silicon dioxide and iron monoxide.

"Reaction of these gases with sulfur and chlorine species in volcanic gases could lead to the formation of such unusual gases as sodium chloride, potassium chloride, magnesium dichloride and iron dichloride, " Fegley said.

In 2000, Fegley and former Washington University colleague Mikhail Zolotov, Ph.D., now at Arizona Sate University, predicted formation of sodium chloride and potassium chloride vapor in volcanic gases on Io. Three years later astronomers found sodium chloride gas on Io. However, these observations were not sensitive enough to detect the less abundant potassium chloride vapor.

Now Fegley has found that sodium and potassium in Ionian volcanic gases are being vaporized from the hot lavas. Fegley and research assistant Laura Schaefer of Washington University used data from the Galileo mission and Earth-based observations from high-powered telescopes in their NASA-funded research. They published their results in the May 2004 issue of Icarus, the leading planetary science journal.

"We're basically doing geology on Io using data from telescopes on Earth, which shows that observations like this can compete with expensive space missions," said Fegley. "It's amazing how hot and how volcanically active Io is. It is 30 times more active than Earth. It's the hottest body outside of the sun in the solar system."

The innermost of the four major satellites of Jupiter - there are at least 16 - Io gets its high rate of volcanism from tidal interactions with Jupiter, which has the strongest magnetic field of all the planets. Over 100 active volcanoes have been identified on Io. Hotspots there have temperatures as high as 1,600 degrees Celsius. This is several hundred degrees hotter than terrestrial volcanoes like Kilauea in Hawaii, which has a temperature of about 1,000 Celsius (1,830 Fahrenheit).

Fegley and Schaefer found that silicon monoxide is the major silicon-bearing gas over the lavas.

"The interesting thing about this is that astronomers have observed silicon monoxide in other environments in interstellar space, most notably in the atmospheres of cool stars," said Fegley.

Astronomical observations of actively erupting volcanoes on Io may be able to detect the silicon monoxide gas in its atmosphere.

Fegley and Schaefer recommend an Io volcanic probe mission to directly measure the pressure, temperature and composition of gases of Pele, one of Io's most active volcanoes. Such an endeavor is "feasible using present technology," Fegley said. "It would vastly expand our knowledge of the most volcanically active body in the solar system."

The volcanic probe mission would represent an advance in the effort to unveil some of Io's mysteries, such as how the satellite, about the size of our own Moon, can maintain its high magma temperatures without being nearly totally molten, and how does Io maintain a strong enough lithosphere to support mountains higher than Mount Everest?

Mars rover collectible patch

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This commemorative patch celebrates NASA's Curiosity rover mission of the Mars Science Laboratory in search of clues whether the Red Planet was once hospitable to life.
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Apollo 11 special patch
Special collectors' patch marking the 35th anniversary of the historic Apollo 11 moon landing is now available.
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Inside Apollo mission control
An insider's view of how Apollo flight controllers operated and just what they faced when events were crucial.
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The ultimate Apollo 11 DVD
This exceptional chronicle of the historic Apollo 11 lunar landing mission features new digital transfers of film and television coverage unmatched by any other.
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Next ISS crew
Own a little piece of history with this official patch for the International Space Station's Expedition 11 crew. We'll ship yours today!
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Apollo patches
The Apollo Patch Collection: Includes all 12 Apollo mission patches plus the Apollo Program Patch. Save over 20% off the Individual price.
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