Subscribe free to our newsletters via your
. Space Industry and Business News .

The Van Allen Probes
by Karen C. Fox for Goddard Space Flight Center
Greenbelt, MD (SPX) Nov 12, 2012

illustration only

Earth's magnetism has captured human attention since the first innovator noticed that a freely moving piece of magnetized iron would always align itself with Earth's poles. Throughout most of history, the origins and physics of this magnetism remained mysterious, though by the 20th century certain things had been learned by measuring the magnetic field at Earth's surface.

These measurements suggested that Earth's magnetic field was consistent with that of a giant bar magnet embedded deep inside Earth. However, the magnetic field observed at the surface of our planet is constantly fluctuating.

During the 1930s scientists pioneered explanations that such fluctuations were due to streams of particles from the sun striking and becoming entrapped within Earth's magnetic field.

Truly understanding Earth's magnetic environment, however, required traveling to space. In 1958, the first US rocket - known as Explorer 1 and led by James Van Allen at the University of Iowa - was launched.

By providing observations of a giant swath of magnetized radiation trapped around Earth, now known as the Van Allen Belts, Explorer 1 confirmed that Earth's magnetic environment, the magnetosphere, was not a simple place.

We now know that it has a complex shape - compressed on the side facing the sun, but stretched out into a long tail trailing off away from the sun - affected as much by incoming material from the sun as Earth's own intrinsic magnetism. This magnetic field constantly fluctuates in response to both internal instabilities and events on the sun. It also provides a home for a host of electrified particles spiraling through this complex system.

A Scientific American article in 1963 said: "Conditions in the magnetosphere are so diverse and so variable . . . that millions of observations by scores of satellites and rocket probes have only begun to plot the broad outlines of this extension of the Earth into space."

The age of magnetospheric science had begun, and it hasn't stopped yet. In 2012, those observations continue with the latest addition to NASA's heliospheric fleet: twin satellites launched on Aug. 30, 2012, originally named the Radiation Belt Storm Probes.

On Nov. 9, NASA announced that to honor the scientist who helped launched the field, the probes will be renamed the Van Allen Probes. The renaming comes simultaneously with a standard milestone for any NASA mission: the end of commissioning. Commissioning occurs after launch when all the instruments have been turned on and tested. The end of commissioning also marks the beginning of the prime science mission.

"We are excited to be honoring James Van Allen in this way," says David Sibeck, NASA's mission scientist for the Van Allen Probes at NASA's Goddard Space Flight Center in Greenbelt, Md. "This is an important mission that carries on early magnetospheric work. In the past we have only had one spacecraft at a time looking at the radiation belts. The state-of-the-art instruments we have now are going to be able to comprehensively observe all the types of particles and waves in this part of the magnetosphere."

Indeed, the preliminary data returned from the Van Allen Probes' first two months already has scientists very excited. The instruments all meet or exceed mission specifications and some papers and publications are already planned based on just the first few weeks of observations.

The probes have a planned two-year mission, each with a similar orbit that will carry the spacecraft through all parts of the radiation belts. The basic goal of the mission is to understand what causes the belts to swell and shrink in response to incoming radiation from the sun. Such changes in the belts can endanger satellites in space that orbit near the belts.

To distinguish between a host of theories developed over the years on the radiation belts, Van Allen Probe scientists have designed a suite of instruments to answer three main questions. Where do the extra energy and particles come from? Where do they disappear to, and what sends them on their way? How do these changes affect the rest of the magnetosphere?

In addition to its broad range of instruments, the mission will make use of its two spacecraft to better map out the full spatial dimensions of a particular event and how it changes over time.

Scientists want to understand not only the origins of electrified particles - possibly from the solar wind constantly streaming off the sun; possibly from an area of Earth's own outer atmosphere, the ionosphere - but also what mechanisms gives the particles their extreme speed and energy.

"We know examples where a storm of incoming particles from the sun can cause the two belts to swell so much that they merge and appear to form a single belt," says Shri Kanekal, the Van Allen Probes' deputy mission scientist at Goddard. "Then there are other examples where a large storm from the sun didn't affect the belts at all, and even cases where the belts shrank. We need to figure out what causes the differences."

Of course, just like Explorer 1, any new spacecraft will provide unexpected observations that can dramatically change the models and theories about a given region of space. The magnetospheric science that James Van Allen helped initiate will surely provide additional surprises as the Van Allen Probes sweep their way through the radiation belts.


Related Links
Van Allen Probes
Space Technology News - Applications and Research

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

UNH Space Scientists to Develop State-of-the-Art Radiation Detector
Durham NH (SPX) Nov 05, 2012
Scientists from the Space Science Center (SSC) at the University of New Hampshire have been selected by NASA to develop a space radiation detector that possesses unprecedented performance capabilities despite a design requiring only minimal resources with respect to mass, volume, power, and cost. The successful UNH proposal, titled "Small active readout device for dose spectra from energet ... read more

India unveils new version of 'world's cheapest tablet'

Buzz building for debut of Wii U videogame console

NASA tests 'interplanetary Internet'

Atmospheric CO2 risks increasing space junk: study

Raytheon BBN Technologies' WNaN next generation network software selected for NIE 13.1 experiment

Raytheon announces Small Format Guard to secure data transfer for mobile and tactical forces

Pentagon to end exclusive deal with RIM's Blackberry

Space Systems Loral Selected by USAF to Develop Next Gen Protected Military Satellite Communications

Ariane 5 is poised for Arianespace's launch with the EUTELSAT 21B and Star One C3 satellites

Ariane 5 orbits EUTELSAT 21B and Star One C3 satellites

Arianespace's heavy-lift Ariane 5 flight is cleared for liftoff with EUTELSAT 21B and Star One C3

NASA's Vehicle Assembly Building Prepared for Multiple Rockets

Gazprom to Launch Two Satellites by Yearend

Research cruise testing EGNOS satnav for ships

Two SOPS accepts command and control of newest GPS satellite

Telit Introduces LTE Module Expanding Automotive Product Line with 4G for North American and European Markets

NGC Signs Danish Composite Manufacturer For F-35 Lightning II Program

F-35 Stopover in Marietta

EU freezes controversial aviation carbon tax

Eglin Completes 500th F-35 Sortie

No Japan electronics bailout, minister hints

Quantum kisses change the color of nothing

Ultrasensitive photon hunter

Northrop Grumman Begins Sampling New Gallium Nitride MMIC Product Line

Storms, Ozone, Vegetation and More: NASA-NOAA Suomi NPP Satellite Returns First Year of Data

NASA's SPoRT Team Tracks Hurricane Sandy

Sizing up biomass from space

NASA Radar Penetrates Thick, Thin of Gulf Oil Spill

China to test 'social risk' of major factories: official

Smog in Indian capital blamed on vehicle increase

USDA Patents Method to Reduce Ammonia Emissions

EU Council adopts marine fuel sulfur cuts

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement