![]() ![]() Findings and observations include multiple belt structures, including a third belt observed shortly after launch definitive answers about particle acceleration processes and the discovery of a nearly impenetrable barrier region that prevents the fastest and most energetic electrons from reaching Earth. The information on particles and waves delivered by the Van Allen Probes has proved to be a treasure trove for space physics research. "The Van Allen Probes verified and quantified previously suggested theories, discovered new mechanisms that can sculpt near-Earth energetic particle populations, and used uniquely capable instruments to unveil unexpected features that were all but invisible to previous sensors." "Over the past six and a half years, the Van Allen Probes have completed three full circuits around the magnetosphere, and measured more than 100 geomagnetic storms," Ukhorskiy said. The Van Allen Probes were designed and built to be resilient in this extreme environment-and even their builders were surprised by their ability to withstand such harsh conditions. When that happens, spacecraft in the belts had better look out: Trouble lies ahead in the form of short circuits, disrupted computer memory, and instrument failure." "But some of their energy penetrates deep into the Earth's field and, through a variety of mechanisms, powers up the radiation belts. "Our magnetic field does a pretty good job of shielding us from these solar blasts," said David Sibeck, a mission scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The Van Allen Probes travel through the inner region of the Earth's geomagnetic field, where charged particles spend their time bouncing between the 'mirror points' in the Earth's magnetic field, forming radiation belts. "Everyone on the mission feels a real sense of pride and accomplishment in the work we've done and the science we've provided to the world-even as we begin the de-orbiting maneuvers." "The spacecraft and instruments have given us incredible insight into spacecraft operations in a high-radiation environment," Mosavi said. Originally designated as a two-year mission because no one believed that a spacecraft could survive longer in the harsh radiation belts that surround Earth, these rugged spacecraft have operated without incident since 2012 and continue to enable groundbreaking discoveries about the Van Allen belts. "Our mission is to obtain great science data and also to ensure that we prevent more space debris so the next generations have the opportunity to explore space as well." "At the new altitude, aerodynamic drag will bring down the satellites and eventually burn them up in the upper atmosphere," said Nelli Mosavi, project manager for the Van Allen Probes at APL. They will launch 20 more balloons sometime in 2014.In February, the Van Allen Probes mission operations team at the Johns Hopkins Applied Physics Laboratory-where the probes were designed and built-began a series of orbit descent maneuvers that will position the satellites for an eventual re-entry into Earth's atmosphere in approximately 15 years. Having launched balloons in early 2013, the BARREL team is back at home building the next set of payloads. They zeroed in on three specific dates in January 2013 with interesting geomagnetic activity to research initially, dates in which the data from the two missions overlaps and is particularly abundant. The BARREL and Van Allen Probes teams work together closely. ![]() By comparing data, scientists will be able to track how what's happening in the belts correlates to the loss of particles – information that can help us understand this mysterious, dynamic region that can impact spacecraft. Scientists need to understand this process better, and even provide forecasts of such space weather, in order to protect our spacecraft.Īs the Van Allen Probes were observing what was happening in the belts, BARREL tracked electrons that precipitated out of the belts and hurtled down Earth's magnetic field lines toward the poles. The belts wax and wane over time in response to incoming energy and material from the sun, sometimes intensifying the radiation through which satellites orbiting Earth must travel. BARREL works hand in hand with another NASA mission called the Van Allen Probes, which travels directly through the Van Allen radiation belts. During this month of bright, sunny days, the BARREL team launched a balloon every day or two into the circumpolar winds that circulate around the pole.Įach balloon floated for anywhere from three to 40 days, measuring X-rays produced by fast-moving electrons high up in the atmosphere. The NASA-funded mission is called BARREL for Balloon Array for Radiation-belt Relativistic Electron Losses and is led by physicist Robyn Millan of Dartmouth College in Hanover, N.H. ![]()
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