To protect the spacecrafts' sensitive electronics, the team added shields around the instruments to prevent the accumulation of electrical charges. We lowered the risk of failure through a rigorous design review process, careful selection of electronics parts, and extensive parts and materials testing." "Radiation can cause damage to electronics, leading to erratic behavior or outright failure. "Designing the spacecraft and instruments to withstand a very harsh radiation environment was the toughest challenge for Van Allen Probes during design and development," said Rick Fitzgerald, who served as the mission's project manager at APL from 2007 to 2012. The probes-known as spacecraft A and B-were the first spacecraft designed to spend years operating within and studying the radiation belts, a region that most spacecraft missions avoid because of the damage hazards of the environment. 30, 2012, the twin Van Allen Probes have delivered to scientists an unprecedented look into the makeup and processes within the belts. Since their launch from Cape Canaveral Air Force Station, Florida, on Aug. In late 2010, engineers at the Johns Hopkins Applied Physics Laboratory prepare to place Van Allen Probes spacecraft "B" in a thermal-vacuum chamber, where the propulsion system would be tested to ensure it could stand up to the range of hot, cold, and airless conditions of outer space. And the publication rate has steadily grown since the mission launch every four days, a new article is published in an international peer-reviewed journal." "Most of these articles are led by authors not directly affiliated with the mission's science teams. "The data from the Van Allen Probes has led to more than 560 articles published in peer-reviewed science journals since the launch of the mission," Ukhorskiy said. 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. 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.
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