Parts of a giant NASA satellite will crash into Earth on Tuesday night, the US space agency warns, but the probability of it being hit is extremely low.
According to the US Army Space Force, the approximately 1,323-pound (600 kg) spacecraft, one of twin probes launched in 2012 to investigate the Van Allen radiation belt, is estimated to re-enter Earth’s atmosphere around 7:45 p.m. EDT.
Most of the ship, he said in a prediction published Monday, will burn up upon re-entry, although some components are expected to survive. There is a small chance, which the Space Force estimates at 1 in 4,200, that someone on Earth could be injured.
“NASA and the Space Force will continue to monitor re-entry and update predictions,” the statement said, adding that there was an initial uncertainty of plus or minus 24 hours in the calculations.
Debris falling from space is not uncommon, and Wired reported in 2009 that over a 40-year period approximately 5,400 tons are believed to have survived re-entry.
But the chances of being hit are low because about 71% of the Earth’s surface is covered by water. A 2011 report from space.com said the overall chance of someone being injured was 1 in 3,200, and for any individual, much lower. “The odds of them hitting you are one in several billion, so they’re pretty low for any individual person,” Mark Matney, a scientist in the orbital debris program office at NASA’s Johnson Space Center in Houston, told the outlet.
One who wasn’t so lucky was Lottie Williams, a resident of Tulsa, Oklahoma, who was walking in a park in January 1997 when she saw a sudden flash of flight, followed by a six-inch piece of metal that hit her in the shoulder.
The small blackened fragment was never formally identified as space debris. But NASA confirmed that the time and place coincided with the re-entry and breakup of the second stage of a Delta rocket that had been in orbit for months. And Williams, who was not injured, remains the only person known to have been struck by falling manufactured space debris.
On Sunday, a piece of meteorite crashed into the roof of a house in Germany, one of approximately 15,000 to 17,000 meteorites that reach Earth each year, although most end up at the bottom of the ocean.
Meanwhile, the Space Force’s advisory about Tuesday’s satellite crash focuses more on where it came from than where or when it will land. The spacecraft is Van Allen Probe A, launched with its twin, Van Allen Probe B, from Cape Canaveral, Florida, on August 30, 2012 on a mission to investigate the Van Allen belts of charged particles trapped by Earth’s magnetic field.
The probes were deactivated in 2019 when they ran out of fuel and could no longer point themselves toward the sun. Early estimates that they would re-enter Earth’s atmosphere in 2034 proved inaccurate, although the second probe is not expected to return before the end of this decade.
