A Nasa spacecraft launched more than a decade ago to study Earth’s dangerous radiation environment is expected to re-enter the planet’s atmosphere on Tuesday, nearly 14 years after it began its mission in space.
The satellite, Van Allen Probe A, is predicted to fall back to Earth at around about 5:15 a.m. IST on March 11, according to the US Space Force. However, the exact timing remains uncertain, with a margin of plus or minus 24 hours.
Weighing roughly 1,323 pounds (about 600 kilograms), the spacecraft is expected to mostly burn up during atmospheric re-entry. Nasa says that while some components may survive the intense heat of re-entry, the risk of harm to people on Earth is extremely low, about 1 in 4,200.
WHAT IS VAN ALLEN PROBE A?
Van Allen Probe A was launched on August 30, 2012, along with its twin spacecraft Van Allen Probe B, as part of a Nasa mission to study the Van Allen radiation belts.
These belts are vast rings of charged particles trapped by Earth’s magnetic field and act as a natural shield against cosmic radiation, solar storms, and the solar wind.
Originally planned as a two-year mission, the spacecraft far exceeded expectations. The two probes spent nearly seven years flying repeatedly through the harsh radiation belts, collecting unprecedented data about how high-energy particles behave in near-Earth space.
The mission, managed and operated by the Johns Hopkins University Applied Physics Laboratory, made several important discoveries. Among the most surprising was evidence of a temporary third radiation belt that can appear during periods of intense solar activity.
CRUSHED BY THE SUN’S SUPERSTORM
Nasa officially ended the mission in 2019 after the spacecraft ran out of fuel and could no longer properly orient themselves toward the Sun to operate safely.
When scientists first calculated the spacecraft’s orbital decay after the mission ended, they estimated it would re-enter Earth’s atmosphere around 2034. However, stronger-than-expected solar activity during the current solar cycle accelerated its descent.
The Sun reached its solar maximum in 2024, producing intense space weather that expanded Earth’s upper atmosphere and increased atmospheric drag on satellites in low orbit, including the ageing probe.
While Van Allen Probe A is now set for an earlier return to Earth, its twin spacecraft, Van Allen Probe B, is expected to remain in orbit until at least 2030.
Nasa says the mission’s data continues to help scientists better understand space weather and its impact on satellites, astronauts, and critical technologies on Earth.
