The Black Knight satellite
Published 19 October 2026 · All guides
In short: the Black Knight is said to be an ancient object of unknown origin orbiting the Earth. The story is not one sighting but several unrelated events, from 1899 to 1998, joined together after the fact. Each piece has a documented ordinary explanation. What follows takes them one at a time, so you can judge for yourself.
The legend as usually told
In most retellings, an object has circled the Earth in a near-polar orbit for thousands of years, often quoted as about 13,000. It is said to have sent radio signals that Nikola Tesla heard, to have been tracked by the military before anyone had launched a satellite, and to have been photographed by astronauts. The name, dark and medieval, does a lot of the work.
1899: Tesla hears something
Working in Colorado Springs, Tesla recorded regular, repeating radio signals he thought might come from another planet. Nothing in his notes connects them to an object in orbit; that link was added decades later. The writer Brian Dunning has pointed out that natural sources of repeating radio pulses, such as pulsars, were not identified until 1968.
1928: long-delayed echoes
In 1928 the Norwegian radio amateur Jørgen Hals noticed his transmissions coming back as echoes seconds after they were sent, far too late for a simple bounce off the upper atmosphere. The physicists Carl Størmer and Balthasar van der Pol studied them. These long-delayed echoes are real and still reported. Their cause is debated, with explanations centring on how radio waves travel through the ionosphere and the plasma around the Earth.
1954: satellites before satellites
In 1954, three years before Sputnik, the UFO writer Donald Keyhoe told newspapers that the US Air Force had detected two satellites in orbit. No country could launch one at the time. Sceptics note that Keyhoe was promoting a book. No Air Force record supporting the claim has ever surfaced.
1960: the "dark satellite"
This is the strongest piece of the story, because it really happened. In February 1960 Time reported that the US Navy had detected a dark object in orbit, suspected to be a Soviet spy satellite. A follow-up identified it as the remains of the Air Force's Discoverer 8, launched in November 1959, which had gone into the wrong orbit. Discoverer was the public name for the Corona spy-satellite programme (see how spy satellites work), which goes some way to explaining why the object was not discussed openly.
1963: an astronaut's sighting that is not in the record
The astronaut Gordon Cooper is often said to have reported a glowing object during his Mercury flight in 1963. There is no record of any such report from the flight.
1973: a message from a star
The Scottish writer Duncan Lunan returned to the 1920s echoes and arranged their delays into what he read as a star map, pointing to the star Epsilon Boötis. He suggested they came from a probe left in orbit about 13,000 years ago, which is where that figure comes from. Lunan later withdrew the idea, describing his own method as unscientific and containing errors.
1998: the photograph
The image most people picture as the Black Knight was taken in December 1998 during STS-88, the Space Shuttle mission that began assembling the International Space Station. It shows a dark, oddly shaped object against the Earth. During that mission the astronauts Jerry Ross and James Newman reported losing a thermal blanket on a spacewalk, and the spaceflight journalist James Oberg, among others, identifies the object as that blanket. NASA catalogues it as debris.
Where the name comes from
Britain had a real Black Knight: a rocket flown from 1958 to 1965 to test re-entry vehicles for the Blue Streak missile. It has nothing to do with the legend, but the name was in the papers at the right time, and it may be why it stuck.
Why it lasts
Each claim on its own is ordinary. Joined together, they make a satisfying shape: a signal, a detection, a photograph, a secretive government. Two of the pieces involve real classified programmes, which makes "they would not tell us anyway" feel plausible. And a dark object in a polar orbit is exactly the kind of thing that is genuinely hard to see.
What can fairly be said is that there is no single sighting of the Black Knight: there is a chain of separate events, and every link in it has a documented, ordinary explanation.
Where Celestrike comes in
Celestrike borrows the atmosphere of this story rather than taking a side in it. Among the foreign satellites in its orbits are a few that answer to no registry, and the game never says what they are. If you know the story, keep an eye on low orbit. Celestrike is a free spy-satellite strategy game for iPhone and Android, played on real orbits — on the App Store and Google Play.