Newly released audio sheds light on Soviet Space Race-era mission
Jodrell Bank Observatory has released an audio recording from a 1968 Soviet mission that was thought to be intended as a precursor to a manned mission to the Moon. The audio recording intercepted by the Jodrell Bank radio telescope is from the unmanned Zond 6 circumlunar mission that, had it been successful, might have put the Soviet Union on the Moon first.
Jodrell Bank is one of the world's most famous radio telescopes. Once the largest and most powerful instrument of its kind in the world, its construction and research by its first director, Sir Bernard Lovell, produced huge advances in technology as well as pioneering studies in radio astronomy.
However, the construction in 1957 of its famous Mark I radio telescope, now called the Lovell Telescope, came at a high price – and not just one measured in pounds, shillings, and pence. In exchange for footing the bill for the massive dish that was so large that it was moved using recycled gun turret components from a pair of battleships, the scientists had to agree to do a bit of highly classified work for the British government.
This turned out to be using the dish as a space tracking antenna to both keep a lookout for any hostile ICBMs coming over the horizon and monitoring Soviet and American spacecraft as they passed overhead.
By 1968, such monitoring was routine, but the Zond 6 mission that launched on November 10 was anything but ordinary. The unmanned Zond 6 was based on the then-new Soyuz spacecraft. Equipped with a special booster stage and carrying a payload of cameras, instruments, and biological specimens, its purpose was to act as a dry run for a manned mission to orbit the Moon.
News of Zond 6 caused conniption fits with Western intelligence agencies, especially at NASA, which had just gained official permission to send the Apollo 8 mission on a lunar orbital mission. The space agency was already playing beat the clock as it worked to prepare the Saturn V rocket, the Apollo spacecraft, and the three men who were going to fly it for the December 21 launch date. If Zond 6 was successful, NASA had every reason to expect a Soviet manned mission to soon follow. How soon was anyone's guess.
Meanwhile, Jodrell Bank under Sir Bernard carried out its listening brief as it intercepted audio transmissions from the spacecraft. The tape recording that has been released 50 years later begins with a series of bleeps, punctuated by Sir Bernard annotating the telemetry with status updates.
"This is Zond 6. This is the Russian probe Zond 6. November the 14th 1968. The time is 01:52 UT. The probe is about one hour's travel away from the Moon," said Sir Bernard in the first of these comments.
In all, the tape covers the period from November 13 to November 17, when Zond 6 returned to Earth. One puzzling inclusion was a human voice speaking in Russian. Whether the voice was a pre-recording aboard the spacecraft or that of someone at mission control that was being retransmitted back to Earth is unknown, but a translation by Nobel-prize winner Professor Sir Kostya Novoselov shows that these were simulated instrument readings that were probably being used for tests or rehearsing the later manned flight.
Despite the drama caused by the mission, Zond 6 proved a setback for the Soviets. Though it successfully reached the Moon on November 14, 1968 and came within 2,420 km (1,504 mi) of the surface, taking pictures before its orbit swung it back to Earth, the mission ended in failure.
Telemetry indicated that the pressure in the hydrogen peroxide tanks used to power the attitude thrusters was dropping, so mission control ordered the spacecraft to roll the tank into direct sunlight to heat it. Unfortunately, this also weakened the pressure seal on the main hatch, allowing air to escape slowly.
This not only killed all the biological specimens, but much of the primitive electronics aboard that relied on air for cooling. With the capsule depressurized, the Zond 6 was still able to carry out the air-skipping maneuver that allowed it to safely enter the Earth's atmosphere, but the main parachutes jettisoned prematurely, causing the capsule to crash into a field in Kazakhstan.
As a result of this and other failures, the Soviets were forced to postpone and eventually cancel their manned lunar mission, clearing the way for Apollo 8 and the Apollo 11 landing on July 20, 1969.
The released recording was uncovered in the Jodrell Bank archives by Professor Tim O'Brien, Associate Director Jodrell Bank Centre for Astrophysics as part of work on a major new exhibition at the center scheduled to open in early 2021. You can listen to it below.
Jodrell Bank Zond 6 audio
Source: University of Manchester