https://en.wikipedia.org/wiki/Judica-Cordiglia_brothers
In the 1960s, the brothers claimed to have heard radio communications taken from secret Soviet Union space missions, including the dying sounds of a suffocating "lost cosmonaut". One of their most famous recordings was made on 28 November 1960. After about an hour of listening to static, the brothers recognised an SOS signal that seemed to be moving away from the Earth. The story was picked up by a Swiss-Italian radio station and the brothers became the station's space experts.
In November 1963, the brothers said they recorded the voice of a female cosmonaut re-entering the Earth's atmosphere in a malfunctioning spacecraft; in the recording she is heard to have cried out, "I am hot" as it burnt up.
In total the Judica-Cordiglia brothers released nine recordings over a period of four years.
The details were as follows:
May 1960, a manned spacecraft reports it is going off course.
November 28, 1960, a faint SOS Morse Code signal is sent from another troubled spacecraft leaving Earth's orbit.[3]
February 1961, a cosmonaut is audibly recorded suffocating to death.
April 1961, a capsule is recorded orbiting the Earth three times before re-entering the Earth's atmosphere just days before Yuri Gagarin made his historic flight.
May 1961, an orbiting spacecraft makes an appeal for help after going out of control.
October 1961, a cosmonaut loses control of his spacecraft which veers off into deep space.
November 1962, a space capsule misjudges re-entry bouncing off the Earth's atmosphere and out into space.
November 1963, a female cosmonaut dies during re-entry.
April 1964, another cosmonaut is killed when his capsule burns up in the Earth's atmosphere.
Since the 1960s critical analysis of the recordings has cast doubt on their provenance. For instance, audio transcripts reveal that none of the cosmonauts, who were supposed to be Soviet air force pilots, followed standard communication protocols, such as identifying themselves when speaking or using correct technical terminology.[4] Likewise all the recordings contain disjointed sentences and grammatical errors (e.g. the meaningless "..аша передача будет теперь", Nov 1963)â†(″аша передача будет теперь″ Translation: "...[o]ur transmission will now...") contradicting the known fact that the Soviet space program only used highly trained, well-educated Russian native speakers from aeronautical backgrounds.[5]
Though some of the transcripts record cosmonauts saying they are leaving Earth's orbit (i.e. heading into interplanetary or "deep" space), the manned Vostok 3KAs could not reach escape velocity because their designs never contained secondary-burn propulsion units. This was inherent to the Vostok programme, a project to put the first Soviet citizens into low Earth orbit and return them safely. OKB-1 only required spacecraft with velocities that could reach Earth orbit (28,160 kilometres per hour (17,500 mph)) far less than the speed needed to break orbit (40,320 kilometres per hour (25,050 mph)). Propulsion units powerful enough to leave Earth's orbit did not begin to appear until the test firing of the RD-270 engine in 1969; and it was not until the N1 moon rocket (with the NK-33 engines) in 1974 that the Soviets built a spacecraft able to reach open space.[6][7] It is impossible to "accidentally" veer off into deep space without firing a rocket engine powerful enough to accelerate to escape velocity.