A long-retired NASA satellite burned up in Earth’s atmosphere over the weekend, the agency has confirmed.
NASA launched the satellite, called Orbiting Geophysics Observatory 1, or OGO-1, in September 1964, the first in a series of five missions to help scientists understand the magnetic environment around Earth. OGO-1 was the first to launch but the last to fall out of orbit; the satellite had circled Earth aimlessly since its retirement in 1971.
But orbiting Earth is a tricky thing to do, since the particles in our plush atmosphere collide with spacecraft and slow them down, even at very high altitudes where the atmosphere is thin. That speed reduction also lowers the spacecraft’s altitude, until reentry becomes inevitable.
The 1,070-lb. (487 kilograms) OGO-1 experienced that inevitability on Saturday (Aug. 29), as NASA had predicted. The satellite re-entered at 4:44 p.m. EDT (2044 GMT) over the southern Pacific Ocean and burned up in the atmosphere, posing no threat to humans, NASA spokesperson Josh Handal told Space.com in an email.
The spacecraft hit the atmosphere about 25 minutes earlier than NASA had forecast, Handal said, resulting in a reentry location east of the agency’s predictions. OGO-1 re-entered about 100 miles (160 kilometers) southeast of Tahiti, he added; in addition to tracking the satellite, NASA received reports of the event from people on the island.
OGO launches continued through 1969, when OGO-5 began orbiting Earth, but all OGO-1’s successors had already re-entered Earth’s atmosphere.