The Amazing Story of the British Schoolboys Who Cracked Soviet Space Secrets

Ah, the science fair project: the dreaded rite of passage for many an elementary or high school student. A chance to stand for hours in front of a crudely adorned tri-fold presentation board and demonstrate to the judges one’s tenuous grasp of the scientific method. For many, these projects trend towards the basic and unambitious: building a baking soda and vinegar volcano, for instance, or observing the growth of bean sprouts, or finding out which brand of toothpaste cleans teeth the best. Rarely do they involve any sort of original or groundbreaking scientific research. But for one group of British schoolchildren in the early 1960s, extracurricular science was serious business. Using little more than second-hand radio equipment, endless patience, and a whole lot of maths, this group of teenage space enthusiasts became one of the world’s preeminent satellite-tracking organizations, helping to unlock the secrets of the secretive Soviet space program at the height of the Cold War. This is the remarkable story of the Kettering Group.

The story of this nearly forgotten chapter in space history begins in October 1957 with one Geoffrey Perry, Science Master and Head of Physics at the Kettering Grammar School for Boys in Kettering, Northamptonshire. Born in 1927, Perry’s interest in space was sparked by German V2 ballistic missiles falling around his home in Essex in 1944 and reading science fiction author Arthur C. Clarke’s classic 1951 nonfiction work The Exploration of Space. In 1954, shortly after becoming a physics teacher at the Kettering Grammar School, Perry learned about the International Geophysical Year or IGY, a global scientific event scheduled for 1957 in which teams from around the world would collaborate on various earth sciences research projects. As part of the IGY, both the United States and the Soviet Union announced that they would launch an earth-orbiting satellite – and for more on this and how the United States’ first satellite program went humiliatingly awry, please check out our previous video Kaputnuk: America’s Largely Forgotten Disastrous First Attempt to Launch a Satellite.

Realizing that space science was likely to feature on his students’ Oxbridge scholarship exams, Perry decided to learn as much about the subject as he could. Thus, when the Soviets launched Sputnik 1, the world’s first artificial satellite, on October 4, 1957, Perry was ready for it. But while most of the world saw Earth’s new man made moon as a portent of Soviet technological and nuclear supremacy, Perry saw it as a way to spice up his physics lessons – particularly for explaining the Doppler effect. Named after Austrian physicist Christian Doppler, the Doppler effect refers to the change in the frequency of a wave in relation to an observer moving relative to the source of that wave. This effect is commonly observed when standing next to traffic; the sound produced by a vehicle will increase in pitch as the vehicle approaches and the sound waves are compressed ahead of it, then decrease as it moves away and the waves are stretched out behind it. But Perry found such analogies rote and boring, and thought that an audio recording of Sputnik’s radio signal changing pitch as it passed overhead would be a more topical and exciting illustration of the Doppler effect in action.

Serendipitously, the new head of Chemistry, Derek Slater, just so happened to be an avid radio amateur, operating under the callsign G3FOZ. Perry approached Slater with his idea and together the two men set up a war-surplus CR-100 shortwave receiver in the back of the school physics lab to intercept Soviet satellite signals. Their first success came on May 16, 1960 when they picked up transmissions from Korabl-Sputnik 1, an unmanned test version of the Vostok capsule that less than a year later would carry cosmonaut Yuri Gagarin into orbit. By carefully measuring the Doppler shift of the signals as the satellite passed overhead and doing some basic trigonometry, Perry and Slater were able to determine the spacecraft’s altitude and inclination, allowing them to plot its orbit around the globe. This, in turn, led to the pair uncovering their first space mystery. Three days after launch, Perry and Slater noticed the satellite’s signals arriving later than usual. The only explanation, Perry deduced, was that the spacecraft had increased its altitude. Indeed, a navigation error had resulted in Korabl-Sputnik 1 firing its retrorockets in the wrong direction, so that instead of falling out of orbit and returning to earth, the spacecraft moved into a higher orbit. The satellite would eventually decay from orbit and reenter the atmosphere on September 6, 1962, with a large piece landing on a street corner in Mantiowoc, Wisconsin.

Buoyed by this success, Perry and Slater continued to accumulate radio equipment and refine their tracking techniques. The physics lessons about the Doppler effect were quickly forgotten; tracking satellites had become an obsession all its own. Part of the appeal lay in the extreme secrecy of the Soviet space program. In an order to project an image of technical superiority, the Soviets only announced launches once the spacecraft had successfully reached orbit. And what little information that was released to the West was typically vague and ambiguous – especially when it came to military spacecraft. But through careful tracking and clever deduction, Perry and Slater were able to tease out some of the secrets of these mysterious craft. For example, on April 26, 1962 the pair detected the launch of Kosmos 4, the first of the Soviet Zenit series of satellites.While at first the purpose of these spacecraft was a mystery, as more and more were launched some tantalizing patterns began to emerge. First, the satellites remained in orbit for only 8 days. As this was long before their orbits were expected to decay naturally, it meant that the Soviets were deliberately returning the spacecraft to earth at the end of their missions. Second, upon reentering and landing on the steppes of Russia, the satellites began transmitting a distinctive locator beacon, indicating they were meant to be recovered intact. And finally, orbital tracking revealed that the satellites were carefully timed to pass over the North American continent in the morning and the evening. It was this final clue which ultimately unlocked the mystery of the Kosmos satellites, for in a eureka moment Perry and Slater realized the significance of the morning and evening flyovers: shadows. At these times of day the sun is low on the horizon, causing buildings and other structures to cast long shadows ideal for orbital photography. This, combined with the short mission duration and recovery beacon, led the pair to deduce that Zenit was a photographic spy satellite. The Zenit satellites would soon become Perry and Slater’s bread and butter, the team going on to classify various different models based on their mission profiles and recovery beacons.

By 1964, however, the satellite tracking project had become too large for Perry and Slater to handle on their own, so they turned to a ready source of labour to help monitor the radios: their own pupils. As Kettering student Robert Christy later recalled:

“Satellite tracking was a lunchtime activity and occasionally out of school at weekends or maybe a little bit after school. One fortunate thing was that the spacecraft we were tracking tended to be launched in the middle of the day our time, because it was the middle of the day Russian time, and they wanted them over certain parts of the earth at certain times of the day. So in fact we could get away with most of the tracking during normal school hours without disrupting things too much. We had a regular watch for one and a half hours, which was the duration of the lunch hour, to guarantee if there was a new satellite in orbit we would receive it, because it had a one and a half hour orbital period.”

From a hobby pursued by two teachers in their spare time, the project quickly became a local institution, known as the Kettering Grammar School Satellite Tracking Group . This name unfortunately belied the fact that some of the first satellite trackers were actually female students from the Kettering High School for Girls, who were taking their A-Level science courses in the Grammar School’s newly-built science block.

In its early years, the Kettering Group was a decidedly shoestring operation. Satellites were tracked using a motley collection of scrounged, borrowed, and cobbled-together radio equipment and an antenna made from copper gas tubing. Signals were timed with an off-the-shelf electric wall clock. A globe with a circular piece of wire served as an analogue computer for calculating orbits, while more complex calculations were carried out using the computer at a nearby garment factory. Yet despite these seemingly crude methods, the Kettering Group soon became one of the world’s preeminent satellite tracking organizations, their expertise sought by governments and research groups around the globe. In 1966, the group went international when 16-year-old Swedish student Sven Grahn contacted Geoffrey Perry about signals he’d received from the Kosmos 104 satellite. The two established a regular correspondence, and Grahn quickly became one of the Kettering Group’s most reliable sources of satellite tracking data. The group soon attracted more international members, including Richard Flagg in Florida, who in 1967 intercepted transmissions between the Soyuz 1 spacecraft and a Soviet tracking ship off the coast of Cuba – and for more on that mission and its tragic ending, please check out our previous video The Most Disastrous Space Mission Ever Executed.

As the Kettering Group collected more and more data, they began to peel back the veil of secrecy surrounding the Soviet space program. As Geoffrey Perry recalled in a 1985 interview:

“In the early days of the space program, the Russians used to wait four or five orbits – which is getting on to six or seven hours – before they would announce they had men in orbit. But with announcements from Kettering…before the spacecraft had even left the Soviet Union, [we would tell] Reuters, Reuters in London would phone Reuters in Moscow, Reuters in Moscow would ask TASS [the Russian state news agency], and TASS would deny all knowledge of it. It must have been embarrassing for them.”

The group’s greatest triumph, however, came in 1966, when they managed to beat the world’s intelligence agencies in cracking a major Soviet secret. While analyzing the orbit of the Kosmos 112 satellite, launched on March 17, 1966, Geoffrey Perry realized that the spacecraft could not have originated from the Baikonur Cosmodrome in Kazakhstan, the regular launch site for Soviet rockets. This indicated the existence of a second, hitherto unknown launch site. Confirmation of his theory came on October 14 with the launch of Kosmos 129, whose orbit crossed that of Kosmos 112 over a town called Plesetsk, 200 kilometres south of Arkangel within the Arctic Circle. Perry announced his findings in a letter to Flight International magazine, which was published on November 10.

At first the letter failed to attract much attention. At the same time, however, Dr. Charles Sheldon at the U.S. Library of Congress was preparing a report to the Senate on the Soviet space program. When the report was reviewed by the CIA, they requested that Sheldon remove a section on the Plesetsk launch complex since its existence was classified as “Top Secret.” To get around this, Sheldon tipped off the Washington press to Perry’s letter in Flight International. News of the Plesetsk launch site soon became public knowledge, allowing Sheldon to present his report uncensored. The Soviets would not officially confirm the existence of Plesetsk until 1983.

This achievement thrust the Kettering Group into the international spotlight, their exploits trumpeted in headlines like “Pentagon Signals a Hit,” “Schoolboys Tune In To a Space Secret”, and “School Sleuths Scoop Space Experts.” Perry, Slater, and their students were profiled in an article for FLIGHT magazine, invited to the House of Commons to take tea with Kettering Member of Parliament Sir Geoffrey de Freitas, and even received a letter of congratulations from Chinese Communist leader Mao Zedong. The team soon began to consult  for various government agencies including the Pentagon and the Royal Air Force, while Geoffrey Perry later became space consultant for Independent Television News and helped present ITN’s coverage of the Apollo 15 mission in 1971. In 1974, he was awarded the Royal Astronomical Society’s prestigious Jackson-Gwilt Medal, previous recipients of which included Clyde Tombaugh, the discoverer of Pluto.

With increased exposure came improved capabilities as the Kettering Group received various donations of equipment such as an RA-217 radio receiver from electronics firm Racal and an advanced programmable calculator from U.S. Ambassador to the UK Walter Annenburg. Using these tools, the group went from strength to strength, gaining increasingly sophisticated insights into the inner workings of the Soviet, American, and other countries’ space programs. Among the historic missions tracked by the group included the first automatic orbital docking by Kosmos 186 and 188 in 1967, the Apollo 11 lunar landing mission in 1969; the first Chinese satellite, Dong Fang Hong 1, in 1970; the first Soviet space station, Salyut 1, in 1971; the first American space station, Skylab, in 1973;  and the Apollo-Soyuz Test Project in 1975. Among their many achievements, the group learned how to unscramble Soviet voice transmissions, allowing them to listen in on Soyuz and Salyut missions. Thus, in June 1971 they became the first westerners to learn that the crew of Soyuz 11 had died in a depressurization accident during reentry, while in 1985 they discovered that Vladimir Vasyutin, commander of Soyuz T-14, had fallen ill, forcing the mission to be aborted after only two of a planned six months in orbit. The group made an important contribution to global safety in 1978 when they discovered that the nuclear-powered Soviet satellite Kosmos 954 was out of control and would reenter the atmosphere somewhere over northern Canada. The spacecraft, complete with its reactor, fell to earth on January 24, spreading radioactive debris over a 600 kilometre swath of the Northwest Territories and sparking a massive cleanup effort codenamed Operation Morning Light. In January 1983 the Kettering Group tracked the failure and reentry of another Russian nuclear satellite, Kosmos 1402, though this time the spacecraft landed harmlessly in the South Atlantic Ocean. For this work, in December 1984 the group was awarded the Royal Aero Club’s Prince of Wales Cup in a ceremony at the London Science Museum.

Geoffrey Perry retired in August 1985 after more than three decades of dedicated service, with Derek Slater following him two years later. With their departure, satellite tracking activities at Kettering Grammar School came to an end. In 1993 the school itself closed and was taken over by the Tresham Institute, serving as the Kettering Technical College until finally being demolished in 2007. But the school and its famous space tracking program left a long legacy, with many of its members going on to enjoy successful careers in the space industry. Sven Grahn, for instance, became General Manager of the Swedish Space Corporation’s Science System Division and was instrumental in the development of the Viking and Freja satellites; while American member Mark Severance became a flight director for McDonnell Douglas in Houston, Texas. Meanwhile, Geoffrey Perry continued to track satellites on his own time and coordinate the Kettering Group’s international activities until his death in 2000, at which point the group ceased to exist. Reflecting on the whole endeavour, Perry saw the Kettering Group as far more than an excuse to use his students to collect data, stating:

“I think the educational value of this was that by inviting them to help me with my hobby, they were being unconsciously taught the scientific method. If you say to a British schoolboy “sit down, lad, I’ll teach you the scientific method”, he’ll say “over my dead body! I want to go and play football!” You say “come and help me track satellites”, then they come, you see, and over the years, they learn the patience of taking readings and recording that data systematically, analyzing it, formulating hypotheses to explain what they’re hearing. When they’ve got a hypothesis, they try to predict from that hypothesis what should happen. They test it. If it happens, good; if it doesn’t happen, you go back and modify it. Then, eventually, you publish it. And that is what the whole of the scientific method is about.”

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Expand for References

Christy, Robert, The Kettering Group, Zarya,


Christy, Robert, Zenit – Korolyov’s Legacy, Zarya,


Grahn, Sven, A Short History of the “Kettering Group,”


Davis, Scott, The Story of the Kettering Radio Group, National Space Centre, August 31, 2016,


Cawley, Laurence, Kettering Cosmos: How School Children Exposed Soviet Secret, BBC News, April 16, 2016,


Grahn, Sven, Space Tracking Notes,


The Story of How a Group of Intrepid Kettering School Pupils Played Their Unique Part in the Space Race, Northamptonshire Telegraph, July 20, 2019,


Moore, Patrick, The Kettering Connection, May 12, 1985,

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