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Posts Tagged ‘atmosphere’

Signs Of Europa Plumes Remain Elusive In Search Of Cassini Data

December 19, 2014 Leave a comment

Image credit: NASA/JPL-Caltech/SETI Institute

Image credit: NASA/JPL-Caltech/SETI Institute

A fresh look at data collected by NASA’s Cassini spacecraft during its 2001 flyby of Jupiter shows that Europa’s tenuous atmosphere is even thinner than previously thought and also suggests that the thin, hot gas around the moon does not show evidence of plume activity occurring at the time of the flyby. The new research provides a snapshot of Europa’s state of activity at that time, and suggests that if there is plume activity, it is likely intermittent.

The Europa results are being presented today at the American Geophysical Union fall meeting in San Francisco and published in the Astrophysical Journal. Europa is considered one of the most exciting destinations in the solar system for future exploration because it shows strong indications of having an ocean beneath its icy crust.

Members of Cassini’s ultraviolet imaging spectrograph (UVIS) team analyzed data collected by their instrument during the brief time it observed Europa in 2001, as Cassini sped through the Jupiter system en route to Saturn. The observations show that most of the hot, excited gas, or plasma, around Europa originates not from the moon itself, but from volcanoes on the nearby moon Io. In fact, from their data, the researchers calculated that Europa contributes 40 times less oxygen than previously thought to its surrounding environment.

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Venus Express Goes Gently Into The Night

December 17, 2014 Leave a comment

Copyright ESA–C. Carreau

Copyright ESA–C. Carreau

ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.

Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24‑hour orbit, traveling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.

However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.

Normally, the spacecraft would perform routine thruster burns to ensure that it did not come too close to Venus and risk being lost in the atmosphere. But this unique adventure was aimed at achieving the opposite, namely reducing the altitude and allowing an exploration of previously uncharted regions of the atmosphere.

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Meteorites Yield Clues To Red Planet’s Early Atmosphere


Geologists who analyzed 40 meteorites that fell to Earth from Mars unlocked secrets of the Martian atmosphere hidden in the chemical signatures of these ancient rocks. Their study, published April 17 in the journal Nature, shows that the atmospheres of Mars and Earth diverged in important ways very early in the 4.6 billion year evolution of our solar system.

Heather Franz, a former University of Maryland research associate who now works on the Curiosity rover science team at the NASA Goddard Space Flight Center, led the study with James Farquhar, co-author and UMD geology professor. The researchers measured the sulfur composition of 40 Mars meteorites—a much larger number than in previous analyses. Of more than 60,000 meteorites found on Earth, only 69 are believed to be pieces of rocks blasted off the Martian surface.

The meteorites are igneous rocks that formed on Mars, were ejected into space when an asteroid or comet slammed into the red planet, and landed on Earth. The oldest meteorite in the study is about 4.1 billion years old, formed when our solar system was in its infancy. The youngest are between 200 million and 500 million years old.

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NASA Begins Launch Preparations For Next Mars Mission


NASA’s next spacecraft going to Mars arrived Friday, Aug. 2, at the agency’s Kennedy Space Center in Florida, and is now perched in a cleanroom to begin final preparations for its November launch.

The spacecraft will conduct the first mission dedicated to surveying the upper atmosphere of Mars. Scientists expect to obtain unprecedented data that will help them understand how the loss of atmospheric gas to space may have played a part in changing the planet’s climate.

“We’re excited and proud to ship the spacecraft right on schedule,” said David Mitchell, MAVEN project manager at NASA’s Goddard Space Flight Center in Greenbelt, Md. “But more critical milestones lie ahead before we accomplish our mission of collecting science data from Mars. I firmly believe the team is up to the task. Now we begin the final push to launch.”

Full Story: http://www.nasa.gov/press/2013/august/nasa-begins-launch-preparations-for-next-mars-mission/

Reports Detail Mars Rover Clues To Atmosphere’s Past


A pair of new papers report measurements of the Martian atmosphere’s composition by NASA’s Curiosity rover, providing evidence about loss of much of Mars’ original atmosphere.

Curiosity’s Sample Analysis at Mars (SAM) suite of laboratory instruments inside the rover has measured the abundances of different gases and different isotopes in several samples of Martian atmosphere. Isotopes are variants of the same chemical element with different atomic weights due to having different numbers of neutrons, such as the most common carbon isotope, carbon-12, and a heavier stable isotope, carbon-13.

“As atmosphere was lost, the signature of the process was embedded in the isotopic ratio,” said Paul Mahaffy of NASA Goddard Space Flight Center, Greenbelt, Md. He is the principal investigator for SAM and lead author of one of the two papers about Curiosity results in the July 19 issue of the journal Science.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-226

Carbon’s Role In Atmosphere Formation


A new study of how carbon is trapped and released by iron-rich volcanic magma offers clues about the early atmospheric evolution on Mars and other terrestrial bodies.

The composition of a planet’s atmosphere has roots deep beneath its surface. When mantle material melts to form magma, it traps subsurface carbon. As magma moves upward toward the surface and pressure decreases, that carbon is released as a gas. On Earth, carbon is trapped in magma as carbonate and degassed as carbon dioxide, a greenhouse gas that helps Earth’s atmosphere trap heat from the sun. But how carbon is transferred from underground to the atmosphere in other planets — and how that might influence greenhouse conditions — wasn’t well understood.

“We know carbon goes from the solid mantle to the liquid magma, from liquid to gas and then out,” said Alberto Saal, professor of geological sciences at Brown and one of the study’s authors. “We want to understand how the different carbon species that are formed in the conditions that are relevant to the planet affect the transfer.”

Full Story: http://news.brown.edu/pressreleases/2013/04/magma

Journal Highlights on History of Mars, Dione’s Atmosphere & Saturn’s Aurora

August 31, 2011 Leave a comment

  • New observations from the Compact Reconnaissance Imaging Spectrometer
    for Mars (CRISM) show the presence of multiple magmatic intrusions in
    the Valles Marineris canyon on Mars
  • A new study indicates that one of Saturn’s moons, Dione, probably has
    a tenuous atmosphere.
  • New observations of Saturn’s southern auroral oval made simultaneously
    in ultraviolet (UV) and infrared (IR) wavelengths show how complex and
    dynamic the auroral oval is.

Full Story: http://www.agu.org/news/press/jhighlight_archives/2011/2011-08-31.shtml