A heavy space probe will fall to Earth today (March 10), eight years earlier than expected, according to NASA.
The 1,300-pound (600-kilogram) Van Allen Probe A will mostly burn up as it enters Earth’s atmosphere, but some components are expected to remain intact. The spacecraft poses a low risk to humans, with a 1-in-4,200 chance of causing harm, NASA said in a statement released Monday (March 9).
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Intense solar activity forcing the probe down much earlier than originally forecast. When the spacecraft ran out of fuel in 2019, NASA predicted it would remain in orbit until 2034. However, that was before the Sun entered its current solar cycle at the end of 2019, and that cycle has been much more active — and peaked earlier – than the researchers expected.
The Sun’s approximately 11-year cycle peaks with an explosive period of activity known as solar maximumwhich trigger more intense space weather events. These events created more atmospheric drag for the fuelless Van Allen Probe A, pulling it out of orbit.
Van Allen Probe A is one of two Van Allen Probes that have been in space for almost 14 years. NASA launched the satellites in 2012 to study the Earth’s two permanent radiation belts, which were named after American physicist James Van Allen.
The radiation belts consist of charged particles trapped by the Earth’s magnetic field. They mainly act as natural shields, protecting the earth from cosmic radiationsolar storms and solar wind.
The Van Allen Probes were designed for a two-year mission, but ended up lasting about seven years. The mission was finally terminated in 2019, when the probes ran out of fuel. Van Allen Probe A’s twin, Van Allen Probe B, is expected to remain in space until 2030, according to NASA.
The probes made a number of scientific discoveries during their period. For example, the spacecraft found that electrons in the radiation belts can be accelerated to near the speed of light by surfing plasma waves ejected from the sun. They also discovered one third radiation belt which form only during periods of intense solar activity.
