A long-lost fragment of space debris is falling toward Earth for a searing re-entry over the Indian Ocean on Friday, but the widely-watched event poses no risk to people.
Nevertheless, aviation and maritime authorities have cautioned pilots and sailors to steer clear of the expected re-entry zone just south of Sri Lanka.
Re-entry is expected at 0618:34.3 GMT (1:18:34.3 a.m. EST), plus or minus 1.3 seconds. That is the time the object is forecast to be 100 kilometers, or about 60 miles, above Earth’s surface, the internationally-recognized boundary of space.
Astronomers with the University of Arizona’s Catalina Sky Survey spotted the mysterious object, known as WT1190F, while scanning the sky for near-Earth asteroids. Scientists had already tracked WT1190F twice in 2013, and a computation of the object’s trajectory last month showed it was on a collision course with Earth.
Experts estimated the object’s density by calculating how much solar radiation pressure — a tiny but constant force — changed its path over the last two years.
The origin of WT1190F is unknown, but it could come from a rocket stage used on one of China’s recent robotic missions, or it could date back to the human voyages to the moon of the Apollo era. The object, about 1 to 2 meters (3 to 6 feet) across, was left in a highly elliptical orbit around Earth taking it twice as far as the moon during each circuit of the planet.
An airborne team of researchers plans to fly near the projected impact site aboard a Gulfstream 450 jet in a bid to observe the entry, which will occur in daylight over the Indian Ocean. For the airborne research team, and observers on the ground if the weather is clear, scientists expect the falling object to produce a bright fireball that should be visible even in daytime.
Chartered by the International Astronomical Center and the United Arab Emirates Space Agency, the Gulfstream 450 flight hosts scientists from the IAC, the UAE Space Agency, NASA’s Ames Research Center, the SETI Institute, the Clay Center Observatory in Massachusetts, Embry-Riddle Aeronautical University, and two researchers from the University of Stuttgart in Germany sponsored by the European Space Agency.