A NASA geophysics satellite's long space odyssey is nearly at an end.
The Orbiting Geophysics Observatory 1 spacecraft, or OGO-1, launched in September 1964 to study Earth's magnetic environment and how our planet interacts with the sun. The satellite gathered data until 1969, was officially decommissioned in 1971 and has been zooming silently around Earth on a highly elliptical two-day orbit ever since.
But OGO-1's days are numbered. New observations show that Earth's gravity has finally caught up with the 1,070-lb. (487 kilograms) satellite, which is expected to die a fiery death in our planet's atmosphere this weekend.
"OGO-1 is predicted to re-enter on one of its next three perigees, the points in the spacecraft's orbit closest to our plant, and current estimates have OGO-1 re-entering Earth's atmosphere on Saturday, Aug. 29, 2020, at about 5:10 p.m. EDT [2110 GMT], over the South Pacific approximately halfway between Tahiti and the Cook Islands," NASA officials wrote in an update Thursday (Aug. 27).
"The spacecraft will break up in the atmosphere and poses no threat to our planet — or anyone on it — and this is a normal final operational occurrence for retired spacecraft," they added.
The new observations come courtesy of the University of Arizona's Catalina Sky Survey (CSS) and the University of Hawaii's Asteroid Terrestrial-impact Last Alert System (ATLAS), both of which independently detected a small object on an apparent impact trajectory.
Analyses by researchers at the CSS, the Center for Near-Earth Object (NEO) Studies at NASA's Jet Propulsion Laboratory in Southern California and the European Space Agency's NEO Coordination Center revealed that the object in question was not an asteroid but rather OGO-1, NASA officials said.
OGO-1 was the first satellite in the six-spacecraft OGO program, whose other members launched in 1965, 1966, 1967, 1968 and 1969. Those five have all come back to Earth, most recently in 2011, re-entering over various patches of ocean.
Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.