NASA's Van Allen Probe A re-entered Earth's atmosphere at 4 pm IST on Wednesday, marking the end of a mission that significantly advanced scientific understanding of the planet's radiation environment.
Launched in 2012 along with its twin spacecraft, Van Allen Probe B, the mission spent years studying the Van Allen radiation belts, which are rings of charged particles trapped by Earth's magnetic field.
These belts play an important role in shielding the planet from harmful cosmic radiation, solar storms, and the constant stream of solar wind that could otherwise endanger astronauts and damage satellites and other technology, according to NASA.
Spacecraft Weighed Over 600 Kg
According to NASA, the Van Allen Probe spacecraft weighed more than 600 kg. As it plunged through the atmosphere, NASA expected most of the spacecraft to burn up due to intense heat and friction.
However, some fragments could potentially survive the re-entry process. As per reports, the space agency said there was a one in 4,200 chance of being harmed by a piece of the probe, which it characterised as low risk.
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Mission Exceeded Original Timeline
The spacecraft and its twin were sent into orbit to gather scientific data about Earth's two permanent radiation belts.
Originally planned as a two-year mission, the Van Allen Probes A and B were launched on Aug. 30, 2012. The spacecraft ultimately operated for nearly seven years, collecting extensive data about the radiation environment surrounding Earth.
NASA eventually ended the mission in 2019 after the probes ran out of fuel and were no longer able to maintain the orientation needed to keep their solar panels pointed at the Sun.
The radiation belts themselves are named after James Van Allen, the scientist who first discovered them in 1958.
Solar Activity Accelerated Re-Entry
When the mission concluded, scientists estimated that Van Allen Probe A would re-enter Earth's atmosphere in 2034. But that prediction changed due to increasing solar activity.
Those earlier calculations were made before the onset of the current solar cycle, which turned out to be far more active than expected. In 2024, researchers confirmed that the Sun had reached solar maximum, triggering stronger space weather events.
These conditions increased atmospheric drag on the spacecraft, gradually lowering its orbit and causing it to re-enter earlier than originally predicted.
Discoveries From The Mission
The Van Allen Probes mission yielded several major scientific discoveries. Among the most significant was the detection of a temporary third radiation belt that can appear during periods of intense solar activity, NASA said.
Van Allen Probe B, the twin, is not expected to re-enter before 2030, according to NASA.
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