Some time before the cancellation of Luna 25, references to future Soviet lunar exploration had already dried up in the Soviet press. In July 1978 it was briefly reported that a lunar geochemical explorer was under consideration and due to fly by 1983, but nothing more was heard of this project. At around that time, NASA was trying to persuade Congress to fund a lunar geochemical polar orbit – with equal lack of result.

The moon was now relatively well known and Keldysh made the argument to the political leadership that the USSR should no longer try to directly compete with the United States. Both he and the director of the Institute of Space Research (IKI in Russian), Roald Sagdeev, argued that the USSR should concentrate on what it was good at, had proven expertise and did not compete directly with the Americans. This pointed the Soviet Union in only one direction: toward Venus. Here, the Soviet Union had parachuted probes through Venus’s atmosphere in 1967 and 1969 (Venera 4, 5-6), soft-landed simple probes on its surface in 1970 and 1972 (Venera 7, 8) and put down sophisticated landers in double missions in 1975, 1978 and 1985 (Venera 9-10, 11-12,
13-14, Vega 1-2). Venera 13 and 14 drilled Venusian soil and analyzed it in an onboard laboratory. Balloons were dropped into the Venusian atmosphere (part of the Vega project). Orbiters first circled the planet in 1975 (Venera 9, 10) and then in 1983 radar-mapped its surface (Venera 15-16). By the end of the Vega programme in 1986, Venus’s surface, atmosphere and circumplanetary space had been well characterized.

Mars took second place in the Soviet programme for interplanetary exploration. The Russian Mars 3 probe became the first spacecraft to soft-land on the Red Planet and sent a picture from its surface in December 1971. The Soviet Union obtained a full profile of the atmosphere right down to the surface during the descent of Mars 6 into the Mare Erythraeum in March 1974. After a gap of many years, the USSR went on to organize an imaginative mission to Mars’s little moon, Phobos, in 1988-9 (the first probe failed, the second achieved limited success). The Americans began a wave of missions to Mars in the 1990s, each one revealing more and more of what an interesting planet it was.

In the light of the genuine progress made in the successful exploration of Venus and the sustained interest in Mars, it is little wonder that the further scientific exploration of the moon became a low priority. Eventually, though, coinciding with a reforming political leadership in the Soviet Union, some plans were advanced. In 1985, the idea of a lunar polar orbiter was resurrected. In 1987, the Institute for Space Research (IKI) in Moscow gave this mission a target gate of 1993, with a lunar farside sample recovery in 1996 and an unmanned laboratory on the moon, with rovers, in 2000. In its last plan for space development published in 1989 (The USSR in outer space – the year 2005), the Soviet Union proposed a lunar polar geophysical orbiter, but few details were given and only a sketchy illustration was published, suggesting it would use the Phobos spacecraft design. At one stage, the project acquired the name Luna 92, indicating a 1992 launch date, but it never got beyond the preliminary design stage and the money originally set aside for it was used for the Mars 96 planetary mission instead.