A spacecraft, weighing over 1,300 pounds, is on track to re-enter Earth’s atmosphere around 19:45 EST (00:45 GMT) on Tuesday. This event is a big deal almost 14 years after the launch in 2012. The mission has provided unprecedented data about the Earth’s radiation belts. These belts are important for protecting our Earth from cosmic radiation and solar storms.
Van Allen Probe A, shown here before launch with its twin, Van Allen Probe B. From 2012 to late 2019, it recorded marvelous details on the rings of charged particles ensnared by Earth’s magnetic field. The stated scientific objective of the mission was to investigate the two natural, permanent radiation belts that lie like hula hoops around the Earth. The probe had made historic discoveries throughout its time alive, including our solar system’s last unexplored frontier. It discovered a temporary third radiation belt, overturning researchers’ longstanding knowledge of these turbulent zones.
The mission extended beyond the original two-year plan. It somehow defied every prediction, running for almost seven years before running out of fuel finally killed it off. One expectation was that the spacecraft would not be able to orient itself toward the Sun, a key capability for its solar-powered operations. The Van Allen Probe A will largely vaporize upon re-entry. Other components could survive their trip through the atmosphere.
As the spacecraft prepares for tumbling home, scientists are nervously watching. In fact, they estimate there’s only a one in 4,200 chance that debris might become dangerous to humans on the ground. That low probability still highlights the precision tracking required in following the probe’s re-entry trajectory.
Van Allen Probe B will continue its orbit for the foreseeable future. It’s not anticipated to return to Earth’s atmosphere before 2030 at the very earliest. Its continued presence will allow researchers to further study the dynamics of the Van Allen belts and their interactions with solar activity.