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Cassini Significant Events 03/14/2012 – 03/20/2012

March 26, 2012 Leave a comment

The most recent spacecraft tracking and telemetry data were collected March 21 using the Deep Space Network’s 34 meter Station 25 at Goldstone, California. The Cassini spacecraft is in an excellent state of health. All subsystems are operating normally except for the issue being worked with the Ultrastable Oscillator. Information on the present position of the Cassini spacecraft may be found on the “Present Position” page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

The Cassini Plasma Spectrometer (CAPS, off since June 2011) was powered back on on March 16 based on the unanimous agreement of the review board at the CAPS turn-on review held on March 8. All went as planned for both the instrument and the spacecraft during the turn-on. The high rail to chassis short internal to the instrument that was part of what prompted it to be turned off last June was not present, and no changes were seen in the bus voltages or currents when the turn-on occurred. On Tuesday, March 20, the high rail to chassis short in the CAPS instrument returned, generating the same condition that existed at the time the instrument was turned off. However, based on the tin whisker model developed by the NESC team, this condition is believed to be understood and is not expected to cause any problems for either the instrument or the spacecraft. The CAPS instrument has been left powered on and is sequenced to operate as originally planned for the 75 kilometer Enceladus flyby coming up on March 27.

Repeating observations this week included two by the Imaging Science Subsystem (ISS) and Visual and Infrared Mapping Spectrometer (VIMS) in the Titan Monitoring Campaign, seven by ISS and VIMS in the Saturn Storm Watch, and three by ISS in the Satellite Orbit Campaign. In the latter, Cassini points toward specific patches of sky near Saturn where small satellites may be found, including some discovered in recent years. Astrometric observations are made of their location in orbit about the planet to refine knowledge of their orbits. These observations can also catch small satellites never seen before.

While the spacecraft was near apoapsis, the Cosmic Dust Analyzer (CDA) made two multi-hour measurements of interstellar dust.

Full Story: http://saturn.jpl.nasa.gov/news/significantevents/significantevents20120326/

NASA’S Grail MoonKam Returns First Student-Selected Lunar Images

March 26, 2012 Leave a comment

One of two NASA spacecraft orbiting the moon has beamed back the first student-requested pictures of the lunar surface from its onboard camera. Fourth grade students from the Emily Dickinson Elementary School in Bozeman, Mont., received the honor of making the first image selections by winning a nationwide competition to rename the two spacecraft.

The image was taken by the MoonKam, or Moon Knowledge Acquired by Middle school students. Previously named Gravity Recovery And Interior Laboratory (GRAIL) A and B, the twin spacecraft are now called Ebb and Flow. Both washing-machine-sized orbiters carry a small MoonKAM camera. Over 60 student-requested images were taken aboard the Ebb spacecraft from March 15-17 and downlinked to Earth on March 20.

“MoonKAM is based on the premise that if your average picture is worth a thousand words, then a picture from lunar orbit may be worth a classroom full of engineering and science degrees,” said Maria Zuber, GRAIL mission principal investigator from the Massachusetts Institute of Technology in Cambridge, Mass. “Through MoonKAM, we have an opportunity to reach out to the next generation of scientists and engineers. It is great to see things off to such a positive start.”

Full Story: http://www.nasa.gov/home/hqnews/2012/mar/HQ_12-093_MoonKam.html

Gas-Guzzling Black Holes Eat Two Courses at Once

March 26, 2012 Leave a comment

Astronomers have put forward a new theory about why black holes become so hugely massive – claiming some of them have no ‘table manners’, and tip their ‘food’ directly into their mouths, eating more than one course simultaneously.

Researchers from the UK and Australia investigated how some black holes grow so fast that they are billions of times heavier than the sun.

The team from the University of Leicester (UK) and  Monash University in Australia sought to establish how black holes got so big so fast.  Their research is due to published in the Monthly Notices of the Royal Astronomical Society.

The research was funded by the UK Science and Technology Facilities Council.

Full Story: http://www2.le.ac.uk/offices/press/press-releases/2012/march/astronomers-put-forward-new-theory-on-size-of-black-holes

Planet Starship: Runaway Planets Zoom at a Fraction of Light Speed

March 26, 2012 Leave a comment

Image Credit: David A. Aguilar (CfA)

Image Credit: David A. Aguilar (CfA)

Seven years ago, astronomers boggled when they found the first runaway star flying out of our Galaxy at a speed of 1.5 million miles per hour. The discovery intrigued theorists, who wondered: If a star can get tossed outward at such an extreme velocity, could the same thing happen to planets?

New research shows that the answer is yes. Not only do runaway planets exist, but some of them zoom through space at a few percent of the speed of light – up to 30 million miles per hour.

“These warp-speed planets would be some of the fastest objects in our Galaxy. If you lived on one of them, you’d be in for a wild ride from the center of the galaxy to the Universe at large,” said astrophysicist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics.

“Other than subatomic particles, I don’t know of anything leaving our galaxy as fast as these runaway planets,” added lead author Idan Ginsburg of Dartmouth College.

Such speedy worlds, called hypervelocity planets, are produced in the same way as hypervelocity stars. A double-star system wanders too close to the supermassive black hole at the galactic center. Strong gravitational forces rip the stars from each other, sending one away at high speed while the other is captured into orbit around the black hole.

Full Story: http://www.cfa.harvard.edu/news/2012/pr201206.html

Modeling Extreme Space Weather

March 26, 2012 Leave a comment

Explosions on the sun regularly disrupt the magnetic envelope surrounding Earth, but that envelope, the magnetosphere, largely protects the surface of the planet itself from space weather – with one exception. As a rule, changes in magnetic fields cause electric currents and vice versa, so all that change in the magnetosphere causes electric currents to form on the ground. Called geomagnetically induced currents or GICs, such currents extend some 60 miles underground, electrifying any conductors – power grid lines, or oil pipes, for example – along the way.

A big enough electrical surge from a GIC can knock out the transformers in a power grid. Electric companies can protect the grid from such surges by shutting down or lowering the power load on the system, but this, of course, costs money so they also don’t wish to be overly cautious by reducing power output unless it is really necessary. New analysis by scientists at NASA’s Goddard Space Flight Center in Greenbelt, Md., published online in Space Weather on February 23, 2012, provides some basic guidelines to help model some of the largest, most damaging GICs.

Risk analysis and adequate risk protection both rely on numerous factors. Modeling an extreme, devastating GIC is a crucial part of that picture. Referred to as 100-year events, that is, events so extreme they only happen on average once every 100 years, such currents could cause significant damage to Earth’s power grids worldwide. But proper preparation and accurate space weather forecasting could mitigate intense damage, the same way that communities can evacuate or protect their homes if given enough advance warning of a hurricane.

Full Story: http://www.nasa.gov/mission_pages/sunearth/news/gic-model.html