The readings were collected by the NASA Van Allen Probes

Mar 10, 2014 08:06 GMT  ·  By

After spending nearly two years in Earth's orbit, the NASA Van Allen Probes, formerly known as the Radiation Belt Storm Probes (RBSP) mission, finally managed to collect sufficient data to enable scientists to create a new and improved model of what goes on in the radiation-filled environment immediately adjacent to Earth. 

The Van Allen radiation belts are two massive, donut-shaped bubbles of radiation around Earth, which contain electrons that can get accelerated to speeds of up to 99 percent that of light. Sometimes, these belts can swell in response to solar activity or other factors, and it is the purpose of the former RBSP mission to figure out how and why that happens.

The twin spacecraft were built by researchers with the Applied Physics Laboratory at the Johns Hopkins University (JHU-APL) near Laurel, Maryland. The probes were launched into orbit on August 30, 2012, aboard an ULA Atlas V delivery system, from SLC-41 at the Cape Canaveral Air Force Station, in Florida. The initial mission is scheduled to run for 2 years, but it may get extended soon.

Understanding the Van Allen belts is very important because their changing characteristics modify the environment through which numerous satellites fly. Planetary scientists want to use the ex-RBSP spacecraft to figure out how these changes occur and, more importantly, determine whether or not they can be predicted well in advance.

For the new investigation – details of which appear in the latest issue of the esteemed journal Geophysical Research Letters – investigators at the Los Alamos National Laboratory (LANL) in New Mexico combined Van Allen Probes data with the results of a simulation conducted in a new computer model that replicates conditions seen near Earth.

“The Van Allen Probes are gathering great measurements, but they can't tell you what is happening everywhere at the same time. We need models to provide a context, to describe the whole system, based on the Van Allen Probe observations,” LANL space scientist Geoff Reeves notes. He coauthored two science papers published in the latest issue of GRL on this subject.

The combination of real and modeled data now enables scientists to simulate what happens in the Van Allen belts in more detail. As more and more information is collected, it can be easily inserted into these models and further refined.

“That gives us some confidence in our model. And, more importantly, it gives us confidence that we are starting to understand what's going on in the radiation belts,” Reeves explains.

The computer simulation used in the new study is called Dynamic Radiation Environment Assimilation Model in 3 Dimensions (DREAM3D) and is hosted on a supercomputer at LANL.