A “missing” satellite, which traveled unnoticed in space for 25 whole years, was spotted a few days ago by astrophysicists.

The lost satellite had begun its journey on April 10, 1974, as part of a test program of the US Space Force.

S73-7 (Infrared Calibration Satellite Balloon) was 66cm wide and was spotted moving in a circular orbit 800km from Earth, among at least 20,000 objects currently orbiting Earth

According to Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, based on data records, S73-7 had disappeared from radar not once, but twice – first in the 1970s and then again in the 1990s.

“The problem is that it was possibly lower than the detection range of the radars. And maybe what they recorded is a mechanism or a part of the balloon that wasn’t built right and, because it wasn’t metal, it didn’t show up well on radar,” he explains.

“If there’s a map of the recent orbital data and the orbital field is not crowded, then it might be an easy identification. However, if it is a crowded spot and the object has not been recorded for a long time, then its identification is far from easy,” says the scientist.

That’s why such a discovery, says McDowell, constitutes a triumph for the people trying to track the tens of thousands of “missing” satellites and other space debris orbiting our planet.