It's not the first time the little spy balloon has disappeared. It is hoped that this time it will be possible to keep an eye on it - unlike last time.

The infrared calibration balloon (IRCB) S73-7 arrived dead at its destination after being launched by one of the US Air Force's largest orbital spy systems during the Cold War.

In 1974, despite successfully decoupling from the KH-9 Hexagon reconnaissance satellite some 800 km above the Earth, the S73-7 failed to inflate to its full diameter of 66 centimeters.

The malfunction prevented it from helping the ground equipment to triangulate the remote sensing arrays, thus making it just another piece of space junk.

Shortly afterwards, recalls Popular Science, US analysts lost sight of the IRCB, and would only locate the small satellite again in the early 1990s - only to lose sight of it again soon afterwards.

Now, another 25 years later, the US Space Force's 18th Space Defense Squadron has rediscovered the experimental device.

The confirmation was made in a recent post on X-Twitter by Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, who offered his "congratulations to whoever analyst made the identification".

So how does a satellite disappear for years on end, not once, but twice? It's actually much easier than you might think.

Space Force finds a dead Cold War-era satellite missing for 25 years
It’s not the first time the tiny spy balloon has disappeared.
Popular ScienceAndrew Paul

As Gizmodo explains, more than 27,000 objects are currently in orbit, most of which are used rockets. These, along with various satellites, do not transmit any kind of identification to Earth.

For this reason, tracking systems have to match a detected object to the predictable orbital path of a satellite in order to identify it.

If there is relatively up-to-date radar data and there aren't many competitors in a similar orbit, it's usually not difficult to identify satellites.

But the more populated an area is, the harder it is to match sensors, especially if the target hasn't been seen for some time - for example, a miniature infrared calibration balloon from the 1970s.

Missing Satellite Found After 25 Years of Being Lost in Space
As it turns out, it’s quite difficult to keep track of 27,000 objects flying around Earth orbit.
GizmodoGizmodo

It's not known exactly what information allowed the Space Force to match the newly detected object with the S73-7, but at least we now know exactly where, above everyone's heads, it is.