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Soviet plans for planetary exploration beyond Mars and Venus The pioneering robotic missions to the Moon, Venus and Mars in the 1960s gave hopes to American and Soviet developers for reaching even more distant and mysterious places in the Solar System, such as the giant planets and their moons beyond the orbit of Mars. In the inner Solar System, Mercury could be explored and even close flybys of the Sun were possible. However, the technical obstacles facing such projects were immensely more serious than in early deep-space missions.
A probe entering Jovian atmosphere as envisioned by Soviet painter Andrei Sokolov. TsNIIMash projects: Galaktika study By 1967, Soviet robots made soft landing on the Moon, entered its orbit, transmitted data from the atmosphere of Venus and attempted a trek to Mars. At the same time, more advanced Venus and Mars landers were in active development or in production at the top-secret Lavochkin design bureau near Moscow. On the another side of the Atlantic, NASA launched its own robotic missions to Mars and Venus, including Mariner-4 which revealed to humanity the first close-up views of the Red Planet during its flyby in 1965. Although the widely-anticipated canals built by a dying civilization were suddenly replaced with Moon-like crater chains and barren landscapes under a thin atmosphere as warned by William Herschel, much more research into the history of the Red Planet was warranted with orbiting and landing missions. At the same time, the US Pioneer-6 and -7 probes cruised through deep space for months and eventually years after their launches in 1965 and 1966, demonstrating the capability to traverse the Solar System. The California-based Jet Propulsion Laboratory, JPL, which oversaw the American planetary exploration program, wasted no time publishing the first proposals for sending robotic missions to the Inner and Outer Solar System along so-called gravity-assisted trajectories, which used the gravitational pull of planets to accelerate the spacecraft and reduce flight time from one destination to another. In 1965, a JPL scientist calculated a trajectory that could take the same spacecraft to Jupiter, Saturn, Uranus and Neptune, if launched in time for a rare planetary alignment between 1976 and 1978. The concept was dubbed Grand Tour and became the theoretical foundation for the Voyager project. (1056) The idea of sending robotic missions beyond the orbit of Mars also appeared on the drawing board of Soviet scientists. In 1967, the industry-wide Galaktika project mandated all the organizations involved in the space program to envision their respective areas of expertise in a decade's time. For the engineers at NPO Lavochkin and their sub-contractors specialized in deep-space robotic spacecraft, it was a chance to study potential spacecraft designs and the necessary technologies for reaching new destinations. The logical next targets were obviously the mysterious giant planets of the Solar System, starting with Jupiter, as well as Mercury and the Sun in the opposite direction. As usual, publications about "Grand Tour" scenario served as an extra impetus. However, NPO Lavochkin already had its hands full with ongoing projects, so its immediate response to the solicitation in the Galaktika project was limited to a description of progressively ambitious Mars probes then already in the company's assembly pipeline. They included M-69, targeted for launch to Mars in 1969, followed by the M-71 and M-73 Mars probes scheduled for launch in 1971 and 1973 respectively. (At least one mission to Venus was also in development at the time under the code-name V-70, and even more advanced Mars probes were apparently on the drawing board under the code-name 7M.) As a result, initial studies of deep-space planetary missions for the Galaktika project were delegated to the TsNIIMash research institute in Korolev, which served as the main assessment and certification center of the Russian space industry. At the time, the institute's Department 12, also known as Department of Spacecraft and led Dr. Lev Golovin, was responsible for brainstorming mission concepts that could be later adopted for development by the industry given necessary resources and funding. During the second half of the 1960s and the beginning of the 1970s, Golovin's group put forward a number of ambitious proposals for robotic missions to the planets, including to Mercury and to Jupiter, along with the project of a piloted expedition to Mars, a lunar base and a big orbital station in the Earth's orbit. In the course of this work, various scaled models of the hardware were built to represent the concepts developed at TsNIIMash. Despite the common misconception that these models were used for testing, veterans of TsNIIMash insisted that they were no more than promotional materials prepared for meetings of high-ranking officials at the Ministry of General Machine Building, MOM, which oversaw the Soviet rocket industry. After two years of research within the Galaktika framework, on Dec. 31, 1969, Director of TsNIIMash Yuri Mozhorin signed off on the Scientific and Technical Report on the results of Subject No. 217 "Galaktika" and parallel study Subject No. 226 entitled "Study of Prospects of Development and Architecture Definition for Robotic and Piloted Space Means for the Exploration of Interplanetary Space and Planets. The final report for Subject No. 226 outlined the technical concepts and the program of planetary exploration with robotic probes. Delivery systems In the Galaktika study, TsNIIMash considered two primary vehicles for launching Soviet planetary missions: the already flying UR-500K rocket (later known as Proton) and the super-heavy N1 which had no luck in tests. Because the Galaktika study found dramatic increase in mass for next-generation Soviet probes, the UR-500K variant was found to be underpowered for most tasks under consideration. As a result, the planners counted on the upgrades of the rocket with a prospective upper stage burning an exotic fluorine and ammonia mixture, or with a 11B91 space tug featuring a nuclear engine but not expected to fly until at least 1977. Zeus: The Soviet Grand Tour (INSIDER CONTENT)
The centerpiece of the plan considered in the Galaktika study was a mission to the outer planets of the Solar System, in part inspired by NASA's Grand Tour project. Mercury and the Sun Also in 1969, the Germes (Hermes) study evaluated a robotic mission to Mercury and a flyby of the Sun at a distance of 0.4 Astronomical Units. Ground control and communications network The Galaktika study also highlighted the inadequacy of the Soviet deep-space communications and control network. During previous missions to Mars and Venus, the existing ADU-1000 ground antennas were used for sending commands and receiving flight control telemetry in decimeter range, while P-400 antennas were used to receive science data and video information in centimeter range. However, the bandwidth of these systems would be too narrow for missions to Jupiter and beyond. Moscow-based NII Priborostroenia, which was responsible for communications infrastructure, used the Galaktika project to propose a 70-meter P-2500 (RT-70) antenna and a transition to new frequencies — 5-centimeter band for spacecraft-to-ground transmissions and 10-centimeter for ground-to-spacecraft connections on prospective planetary missions. The P-2500 antenna for the Kvant-D ground radio system, NRTK, was actually built and operated in Yevpatoria, Crimea, and in Ussuriisk, in the Russian Far East, and became the most tangible result of the Galaktika project. The 1980s: Energia- and Proton-based projects All original hopes of Soviet scientists for sending probes to the outer Solar System were put on hold by the cancellation of the N1 rocket development in 1974. The most ambitious and mass-demanding missions had to wait until the emergence of a new-generation super-heavy launch vehicle. When the mighty Energia rocket appeared on the horizon in the early 1980s, Soviet engineers re-visited the subject with two preliminary studies, known in Russian as NIRs, One code-named Vselennaya ("Universe"), was initiated in 1982, while the Rasplav ("Melter") study was conducted in 1983. They conceptualized electrically propelled, nuclear-powered space probes which would head to the outer planets of the Solar System and land on their moons. They would deliver rovers and even return soil samples from the mysterious natural satellites of the giant planets. But as before, this work did not go beyond a very preliminary level, most likely due to associated cost and remaining technological obstacles. However, new advances in electronics and in nuclear power sources opened some prospects for fitting long-lasting spacecraft into smaller rockets. During 1986 and 1987, Vladimir Perminov, a leading developer of interplanetary probes at the Lavochkin design bureau, prepared a Scientific and Technical Report, NTO, on the possibility of unmanned missions to Jupiter, Saturn and Sun. The document considered possible designs of the spacecraft, its trajectories and other engineering issues. Based on this work, Lavochkin then initiated a preliminary study, NIR, code-named Tsiolkovsky, whose primary subject was a robotic mission to the Sun. The spacecraft would be powered by Radioisotope Thermal Generators, RTG, which would use radioactive plutonium to produce electrical power onboard. A large four-meter antenna would be used to transmit data from the spacecraft to the ground control stations. A major requirement for the project was the probe's ability to fly within five or seven of the Sun's radiuses. In order to survive the tremendous heat reaching this distance from the Sun, engineers proposed two alternative shapes for the spacecraft body -- one as a narrow cone and another as a disc. In both cases, the narrow edges of the craft would face the Sun, thus reducing the effect of the heat. With all protective measures in place, the temperature of the probe surfaces was still expected to reach 2,500 degrees C. A special thermal protection made of vanadium was designed to shield the probe's internal systems. According to the plan, in 1995-96, a Proton rocket upgraded with a Shtorm (gale) hydrogen-fueled upper stage would send a two-ton spacecraft toward Jupiter, where the planet's powerful gravity field would "sling shot" the probe back toward the Sun in a gravity-assisted maneuver. As it was passing Jupiter, cameras onboard the spacecraft were expected to conduct observations of the giant planet and its moons, while a descent capsule with science instruments would be dropped into Jupiter's atmosphere. The capsule, with a maximum weight of 500 kilograms, was expected to experience the deceleration of 1,500 G during its descent into the atmosphere of Jupiter. Following the Jupiter flyby, the craft would continue on toward the Sun. A derivative of the same vehicle could be also sent toward Saturn and beyond. To simulate the loads expected during the descent in the Jovian atmosphere, NPO Lavochkin design bureau constructed a special centrifuge on its premises in Moscow. However, the spacecraft itself never went beyond the design stage, as federal funds for space program started evaporating at the turn of the 1990s. During 1986-1988, following the USSR's successful flyby of the Halley Comet, Soviet and French representatives evaluated similar mission scenarios, which would bring spacecraft either to an asteroid or a comet. Post-Soviet plans for deep-space spacecraft After a long hiatus caused by economic problems of the post-Soviet period, NPO Lavochkin's engineers could at least dream again about deep-space missions. In August 2007, management of the company revealed plans for a number of missions beyond the Earth's orbit, including the Asteroid-Grunt and Kometa-Grunt projects, which could collect soil samples from an asteroid and a comet respectively. Both probes would be based on the Phobos-Grunt spacecraft, then scheduled for launch in 2009. Beyond the already approved Federal Space Program ending in 2015, NPO Lavochkin drafted plans for yet-to-be funded missions to the outer reaches of the Solar System. Preliminary plans for a lander or a penetrator mission to Jupiter's moon Europa were under discussion between European and Russian officials around the same time with a potential launch date as early as 2017. NPO Lavochkin's documents also described several possible concepts of planetary missions, including:
The actual implementation of all these plans depended on the success of Russia's initial attempts to jump-start its planetary exploration program, as well as on funding of the Russian space program and the ability of Russian scientists to forge cooperative agreements with their colleagues abroad. Russia to send spacecraft into vicinity of the Sun In 2012, the Russian space agency gave the go ahead to the development of an ambitious spacecraft dedicated to studies of the Sun at a close distance. The first Russian or Soviet mission into the vicinity of the Sun faced many unprecedented technical challenges including the development of innovative electric engines and of the protection system to shield the spacecraft from the searing 600-degree heat and radiation of our home star. Dubbed Intergelio-Zond or IGZ, the daring space probe would follow in the footsteps of the the US-German Helios mission and NASA's Ulysses spacecraft. It was also expected to coincide with the US Solar Probe and the European Solar Orbiter projects. Around the time when NASA resumed its exploration of Mercury with the Messenger mission in 2008, Moscow-based Space Research Institute, IKI, also revisited this exotic destination in the Solar System. According to IKI, a three-phase study, NIR, of the Mercury-Landing Module, MPM, evaluated "scientific and technical proposals for the scientific objectives and equipment for the exploration of the planet's surface." Again, the Russian mission to Mercury had never materialized, but scientists at Moscow Space Research Institute, IKI, managed to squeeze their experiment gear on Europe's Bepi Colombo mission that successfully departed toward the planet. Renewed Russian-European cooperation could propel it all the way to JupiterA steady increase of the Russian space budget in the first decade of the 21st century also revived hopes among the nation's planetary scientists for sending a mission to Jupiter. In 2012, Russia also promised to provide three Proton rockets to launch Europe's cash-strapped ExoMars-2016, ExoMars-2018 missions and the JUICE Jupiter spacecraft, essentially bailing out the beleaguered projects. The move gave Russian scientists an early opportunity to see their instruments and experiments reaching Mars in 2016 and 2018 and, in the following decade, flying beyond it, all the way to the moons of Jupiter. However, only ExoMars-2016 was ultimately launched on Proton, while cooperation on two other projects was derailed by the Kremlin's invasion of Ukraine in 2014.
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