The Bulgarian cosmonaut program refers to human spaceflight efforts by the People's Republic of Bulgaria. The idea of a Bulgarian crewed space mission predated the launch of Sputnik 1, the first artificial satellite. An informal proposal for the Soviet Union to send a Bulgarian cosmonaut in space was issued in 1964, but it was not seriously considered by the Soviets. Official space cooperation began in 1966 with the establishment of the Interkosmos programme which allowed Communist Bloc countries to access Soviet space technology and assets.
Under Interkosmos, Bulgaria sent its first cosmonaut, Georgi Ivanov, to the Salyut 6 space station in 1979 and became the sixth country in the world to have a citizen in space. However, a malfunction in his Soyuz 33 spacecraft prevented the crew from docking, and Ivanov only spent 31 orbits around Earth before safely descending back to Earth. A second Bulgarian cosmonaut, Aleksandar Aleksandrov, spent ten days on the Mir Space Station in 1988 and performed a variety of scientific experiments.
Background The launch of Sputnik 1 in October 1957 provided impetus for the first steps of space research in Bulgaria. Radio signals from the satellite were studied by the Ionospheric Radio Measurement and Control Centre, established the previous year. A station for optical tracking of Sputnik 1 was set up in November 1957 on Plana mountain. Influenced by these events and publications of the International Astronautical Federation, engineer Georgi Asparuhov and Bulgarian Air Force captain Docho Haralampiev decided to introduce the wider public to the topic of space exploration. Haralampiev was also convinced that if a human were to fly in space next, the candidate had to be a pilot in excellent physical and mental condition. The two initiated a series of meetings with Bulgarian Army generals, pilots, aviation doctors, engineers, Bulgarian Communist Party members and Bulgarian Academy of Sciences representatives.
As a result, the first dedicated space research body in Bulgaria, the Astronautical Society (BAS), was established in Sofia on 8 December 1957. The rigid legal environment at the time prevented it from being formed as an independent entity, and it was initially organised as an Astronautics Section of the Defence Assistance Organisation. Shortly after the Society's establishment, dozens of engineers and workers from the recently closed Factory 14 became members of the BAS. The Society joined the International Astronautical Federation in 1958. In 1959, the first Bulgarian book on human spaceflight, The Human Organism and Interplanetary Flight, was published.
The intensity of the Space Race increased further after Yuri Gagarin became the first human in space. In 1964, Bulgarian Air Force commander-in-chief Lt. Gen. Zahari Zahariev discussed with Soviet defence minister Rodion Malinovsky the possibility to send four Bulgarian pilots, the Stamenkov brothers, into space. Malinovsky did not consider the request a serious one, especially given the lack of Soviet spacecraft that could carry all four of the brothers. The Soviet Union established its own body for international cooperation in space research, known as the Interkosmos council, in May 1966. As a Communist Bloc state, Bulgaria became one of its founding members.
Bulgarian leader Todor Zhivkov subsequently ordered the establishment of the National Committee for the Research and Utilisation of Space (NCRUS) in February of the following year. NCRUS became a member of the Interkosmos council in April. By the end of 1967 the Committee adopted a programme of activities that included the development of joint Soviet-Bulgarian satellite instruments and studies on human physiology in microgravity. Space activities were further concentrated under the Group of Space Physics under the Academy of Sciences in 1969, which became the Central Laboratory of Space Research (CLSR) in 1974.
Bulgaria became actively involved in all components of Interkosmos. Instruments were placed in Vertikal sounding rockets, several satellites of the Interkosmos series, and ground control activities were carried out in cooperation with the Soviet Union and other Communist countries of the programme. Bulgarian participation in crewed Interkosmos missions was part of the programme's broader Soviet objective of assisting Communist bloc countries in space research. Furthermore, Interkosmos member countries were largely relieved of financial costs as the USSR virtually financed all R&D activities, flights and technology sharing. Member states only financed specific experiments in which they were interested. When the decision to extend Interkosmos cooperation to human spaceflight was taken in 1976, selection of candidates was made easier by nearly a decade of cooperation before that.
Interkosmos flight
Selection for the second Interkosmos cosmonaut class in Bulgaria was carried out in 1976–1977. Bulgarian pilots who graduated at the Dolna Mitropoliya Air Force Academy between 1964 and 1972 were eligible for selection. Almost all of these graduates applied and were sent for medical examination by an aviation medicine commission. Candidates who passed the first round of tests were then sent to the Senior Military Medical Institute in Sofia and subjected to several weeks of examinations in isolated conditions. Only four candidates made it through the second round: Georgi Ivanov Kakalov, Aleksandr Aleksandrov, Georgi Yovchev and Ivan Nakov. A final round of examinations in Moscow in 1978 affirmed Ivanov and Aleksandrov as the most physically fit, and they were approved as prime and backup, respectively.
The Interkosmos mission flight crew consisted of an experienced Soviet cosmonaut as a flight commander, while the member state cosmonaut served as a flight engineer or a research cosmonaut whose role was to oversee their assigned experiments and equipment. Training was meticulous and intensive. The first phase included theoretical studies, flight practice in jet aircraft, weightlessness simulation, splashdown training, physical exercise, and retrieval training in difficult terrain. The second phase was more specific and concentrated on mastering the Soyuz spacecraft and the flight to the Salyut space station.
Experiments In general, Interkosmos flights focused on five main areas of research: space physics, space meteorology, communications, space biology and medicine, and studies of the natural environment. Ivanov's mission was focused primarily on space physics, communications and environmental studies. In December 1978, Spektar-15, a Bulgarian-made spectrometric system, was installed on the Salyut 6 training mock-up at Yuri Gagarin Cosmonaut Training Center. It was subsequently approved for space use. Elements of the Spektar-15 were delivered to Salyut 6 on 14 March 1979 with the Progress 5 flight; these included the data storage block, the eyepiece, lens and filters. Ivanov's experiments on the Spektar-15 or other equipment previously installed in the station includes the following:
Ekvator: observations of atmospheric glow associated with ionospheric anomalies above the Equator; Polyus: observation of polar aurorae; Emisiya: distribution of the intensity of the main spectral lines of the atmospheric glow spectrum; Svetene: photometric observations; Gama-fon: various Gamma-ray astronomy observations intended to improve gamma-ray telescope designs; Oreol: observations of sunrise and sunset to determine basic parametres of the atmosphere; Kontrast: studies on changes in frequency response in the atmosphere caused by pollution near major industrial centres; Atmosfera: study of optical characteristics of the atmosphere; Ilyuminator: precise measurement of the changes in spectral characteristics of light coming through the station's windows; Horizont: photographic observation of the Solar meridian at sunrise and sunset; Terminator: studies of the higher atmosphere; Biosfera-B: collecting data of use for studies in geology, geomorphology, agriculture and forestry, and pollution; Balkan: photography and spectrometry of various natural features on Bulgarian territory; Operator: evaluation of the mental productivity dynamic during adaptation to microgravity; Doza: studying irradiation doses in various parts of the space station; Opros: continuation of psychological experiments from earlier missions designed to improve cosmonaut training systems; Retseptor: studies on the functioning of human taste receptors in microgravity; Pochivka: an experiment designed to improve the organisation of rest in long-duration spaceflight; Vreme: studies on the subjective perceptions of time among the crew; Pirin: five experiments designed to observe the influence of microgravity on materials production.
These were to be carried out alongside cosmonauts Vladimir Lyakhov and Valery Ryumin. Spektar-15 was later used by Cuban cosmonaut Arnaldo Tamayo Méndez.
Flight
Soyuz 33 was launched from the Baikonur Cosmodrome (Kazakhstan) with Ivanov and flight commander Nikolay Rukavishnikov on 10 April 1979. The crew call sign was Saturn. The flight was scheduled to dock with Salyut 6-Soyuz 32 on 12 April (Cosmonautics Day). Upon approaching the Salyut, however, the final engine firing lasted only three seconds instead of six and the Igla docking system switched off. The Soyuz' main engine had malfunctioned and docking maneuvers were now impossible. Salyut crew member Lyakhov also observed a sideways jet toward the auxiliary engine during the failed main engine firing.
The Soyuz 33 had limited life support resources and the crew had to return to Earth immediately. Flight control ordered the Soyuz crew to shut down the main engine completely in order to preserve its fuel supply. There were two options: begin descent on a very soft trajectory, which would land the spacecraft several thousand kilometres from the planned landing point, or a steep descent that would have subjected the crew to very high g-strain. In both cases the Soyuz would have relied on the auxiliary engine, which was confirmed to have been damaged as well. The crew initiated a steep descent and manually programmed the auxiliary engine to run for 187 seconds, slowing down the spacecraft enough to place it in a landing corridor. Rukavishnikov, who had excellent command and experience of the Soyuz flight systems, switched off all automatic landing programmes. With the descent in progress, both Ivanov and Rukavishnikov felt that the damaged auxiliary engine had not provided enough impulse and decided to run it for another 25 seconds to further reduce the landing velocity.
The Soyuz 33 landed surprisingly close to the initially scheduled landing point. Rukavishnikov and Ivanov's handling of the situation received praise. The crew, however, had discarded the service module with the malfunctioning engine and the final component of the Spektar-15, an optoelectronic block, before descent. This meant that the malfunction could not be examined and a new Spektar optoelectronic block had to be produced for future missions. It was later integrated with the rest of the equipment on Salyut 6 and the Bulgarian experiments were initiated in 1981 by Soviet cosmonauts. Despite the aborted mission, Bulgaria became the fourth Interkosmos country (after Czechoslovakia, Poland and East Germany, in that order) and the sixth in the world to send a citizen in space. Ivanov's flight lasted one day, 23 hours and one minute, completing 31 orbits.
Shipka Programme