Vanguard 1 is the oldest satellite still in orbit

Vanguard 1, launched by the US Naval Research Laboratory from Cape Canaveral on March 17, 1958, is the oldest human-made satellite still in orbit. It was only the fourth satellite ever launched, after Sputnik 1, Sputnik 2 and Explorer 1, and the only one of the four that has not since fallen back to Earth.

It was tiny: an aluminum sphere about 16.5 cm (6.4 inches) across, roughly the size of a large grapefruit, weighing just over 3 pounds, with six short antennas. Inside were two radio transmitters, one running on a battery and one on six small solar cells, making it the first solar-powered satellite.

The road from “Flopnik”

• 1955: NRL engineer Roger Easton co-writes the original Vanguard proposal. He was later honored for his role in inventing GPS.
• December 6, 1957: The first attempt, Test Vehicle 3, rises about 4 feet off the pad, loses thrust and falls back in a fireball. The press calls it “Flopnik” and “Kaputnik.”
• March 17, 1958: TV-4 reaches orbit, and only then becomes Vanguard 1.
• 1964: Contact with the solar transmitter is lost after six years of signals.

The solar cells were an afterthought. Easton heard that Bell Labs had developed small solar cells and pushed to add a solar-powered transmitter. It paid off: the battery transmitter died in about a month, as expected, while the solar one kept going.

Those signals had real scientific value. Tracking Vanguard 1’s orbit, which ranged from about 400 to 2,400 miles up and proved exceptionally stable, showed that Earth is not a perfect sphere but slightly asymmetrical, often described as pear-shaped. Silent for six decades, it now holds a second title as the oldest piece of space junk in orbit.