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Atmospheric study shows effects on Earth and Mars APPLIED PHYSICS LABORATORY NEWS RELEASE Posted: May 26, 2006 "Despite differences in the chemical compositions and densities of Earth's and Mars' atmospheres, we now have a definitive example showing that both planets' atmospheres react similarly to varying levels of solar energy impacting them during the sun's 25-day rotation," says Elsayed Talaat, a space scientist with the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. Talaat's findings, which were presented in an AGU session (Comparative Planetology: Atmospheres and Aeronomy I) on May 26, could help the atmospheric science community better understand the relationship between the sun and its effects on planetary atmospheres. Comparing limited ionospheric data sets acquired in 2003 by NASA's Mars Global Surveyor (MGS) and the agency's TIMED SEE instrument (Solar Extreme Ultraviolet Experiment), Talaat says his findings provide evidence that the photochemistry of Mars' ionosphere responds similarly as Earth's to solar inputs. "The upper atmospheres of both planets are impacted by varying levels of high-energy solar X-rays and extreme ultraviolet radiation during the sun's rotation - the same type of data collected by the SEE instrument," Talaat says. "I looked at the variation in solar irradiance found in SEE's data and correlated that with the variability in Mars' ionosphere." To compensate for the sun's different rotational time periods as would be perceived from Earth and Mars, he shifted SEE's data to match the Mars timeframe. When two charts depicting the Mars peak ion density and solar activity levels during a common timeframe were overlaid, the plots aligned. The Mars ionospheric profiles were retrieved from the radio transmissions from NASA's MGS Radio Science Experiment led by Dr. David Hinson of Stanford University. About TIMED Since its launch in 2001, TIMED has been exploring one of Earth's last atmospheric frontiers - the Mesosphere and Lower Thermosphere/Ionosphere (MLTI) - collecting valuable data during various phases of the solar cycle. To date, TIMED and a worldwide network of ground-based observation sites have collected unprecedented global observations of the MLTI region's basic structure, temperature, pressure, wind and chemical composition, as well as measurements of the region's energy inputs and outputs. TIMED is the first mission to simultaneously measure all critical parameters so that scientists can better understand the processes that control changes in the upper atmosphere. TIMED is the first mission in NASA's Solar Terrestrial Probes Program, and is part of the Heliophysics Great Observatory - a collection of NASA's sun-Earth-focused missions. NASA Goddard's Solar Terrestrial Probes Program Office, in Greenbelt, Md., oversees the mission, sponsored by NASA's Science Mission Directorate, Washington, D.C. APL built and now operates the spacecraft, leads the project's science effort and manages the mission's Science Data Center for NASA. The Applied Physics Laboratory (APL) is a not-for-profit laboratory and division of The Johns Hopkins University. APL conducts research and development primarily for national security and for nondefense projects of national and global significance. APL is located midway between Baltimore and Washington, D.C., in Laurel, Md. |
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As night fell over Kennedy Space Center on May 19, space shuttle Discovery reached launch pad 39B to complete the slow journey from the Vehicle Assembly Building. Discovery will be traveling much faster in a few weeks when it blasts off to the International Space Station.
The November 1985 flight of space shuttle Atlantis began with a rare nighttime blastoff. The seven-member crew, including a Mexican payload specialist, spent a week in orbit deploying three communications satellites for Australia, Mexico and the U.S. And a pair of high-visibility spacewalks were performed to demonstrate techniques for building large structures in space. The crew narrates the highlights of STS-61B in this post-flight crew film presentation.
Eight astronauts, the largest crew in history, spent a week in space during the fall of 1985 aboard shuttle Challenger for mission STS-61A, the first flight dedicated to the German Spacelab. The crew worked in the Spacelab D-1 laboratory conducting a range of experiments, including a quick-moving sled that traveled along tracks in the module. A small satellite was ejected from a canister in the payload bay as well. The astronauts narrate the highlights of the mission in this post-flight film.
Perched atop a trailer-like transporter, space shuttle Discovery was moved May 12 from its hangar to the 52-story Vehicle Assembly Building for mating to its external fuel tank and twin solid rocket boosters in preparation for the STS-121 mission.
The U.S. Astronaut Hall of Fame inducted its 2006 class of shuttle commanders Henry Hartsfield, Brewster Shaw and Charles Bolden. The ceremony was held inside the Saturn 5 museum at Kennedy Space Center.
NASA's twin Solar Terrestrial Relations Observatory satellites (STEREO) arrive via truck at the Astrotech processing facility outside Kennedy Space Center for final pre-launch testing and preparations. They will be launched this summer aboard a Boeing Delta 2 rocket to provide the first 3-D "stereo" views of the sun and solar wind.