The Soviet Union’s first dedicated Mars attempt, Marsnik 1 (Mars 1960A), lifted off but failed before reaching Earth orbit. This early loss showed how difficult it was to build a reliable multi-stage rocket and spacecraft for interplanetary flight. It set the pattern for the program’s early years: ambitious goals, but limited launch reliability.
A second attempt just four days later, Marsnik 2 (Mars 1960B), also failed to reach orbit. With two failures in the same Mars launch window, the Soviet program had to regroup and improve both its rockets and its mission planning. The results highlighted that reaching Mars required not only a good spacecraft, but also consistently successful launch vehicles.
Sputnik 22 was launched as another Mars flyby attempt, but it achieved only Earth orbit and did not depart for Mars. This kind of partial failure was different from a launch-pad loss: the rocket worked well enough to orbit, but not well enough to begin the interplanetary journey. The mission underscored that deep-space missions demanded reliable upper stages and precise timing.
Mars 1 (Sputnik 23) became the first Soviet spacecraft launched successfully onto a trajectory toward Mars. It returned data during its cruise through interplanetary space, showing that the USSR could send instruments far beyond Earth. However, the mission’s main test—operating through the full cruise and Mars encounter—was still ahead.
Controllers lost radio contact with Mars 1 before it reached Mars, ending its chances to return close-up planetary observations. The failure showed that long-distance communications and onboard reliability were as critical as launch success. Even so, Mars 1 marked an important step from “did not reach orbit” to “traveled deep into space.”
Zond 2 launched as a follow-up Mars flyby mission, aimed at gathering data and possibly returning images. It reflected a continued Soviet commitment to Mars during the 1960s, even after earlier communication problems. The mission also fit into a broader set of Soviet planetary probes that reused and modified spacecraft designs across targets.
Zond 2 ultimately passed Mars but its radio system failed, so it returned no Mars data. This repeated the program’s earlier weakness: spacecraft could be launched toward Mars, but maintaining communications through the cruise phase remained difficult. The outcome helped drive later emphasis on more robust spacecraft systems for the 1970s missions.
Mars 2 launched as part of a new, more complex mission type: an orbiter paired with a lander. This was a major change from earlier flyby attempts and showed the Soviet program’s push toward direct surface exploration. The mission’s design aimed to study Mars from orbit and attempt delivery of a lander to the surface.
Mars 3 launched days after Mars 2 as an essentially twin spacecraft, improving the odds that at least one orbiter and one lander would succeed. Flying two similar missions in one launch window also let engineers compare performance and learn faster. Together, Mars 2 and Mars 3 represented the Soviet Union’s strongest Mars effort to date.
The Mars 2 lander failed during descent and struck the surface, becoming the first human-made object to reach Mars, though not as a successful landing. Its companion orbiter entered Mars orbit and returned observations, but conditions were challenging during arrival. This mixed result was a turning point: orbiting Mars was achievable, but landing remained extremely difficult.
Mars 3 achieved the first soft landing on Mars, a historic first for planetary exploration. The lander began transmitting but stopped after only a short time, limiting its scientific return. Even with the quick failure, the landing proved that controlled descent and touchdown on Mars were possible.
Mars 4 launched in 1973 as an orbiter but failed to enter Mars orbit, passing the planet instead. The mission still demonstrated that the USSR could deliver spacecraft to Mars reliably, even when key maneuvers failed. These outcomes emphasized that navigation and engine performance at arrival were as important as launch success.
Mars 5 launched as another orbiter, part of a coordinated Soviet campaign that also included Mars 6 and Mars 7. The strategy aimed to gather stronger orbital data and attempt surface delivery again, building on the partial successes of 1971. This “fleet” approach also reduced risk by not relying on a single spacecraft.
Mars 6 launched carrying a lander intended to enter the Martian atmosphere and send data during descent. Unlike Mars 2 and Mars 3, it used a flyby bus rather than an orbiter to support the lander. The mission showed continued emphasis on atmospheric entry and surface access, even as earlier landers had struggled.
Mars 7 launched with a lander similar in purpose to Mars 6, aiming for another try at descent and surface contact. The lander later separated too early and missed Mars, showing how sensitive these missions were to timing and control. By this point, the biggest barriers were no longer “can we reach Mars,” but “can we execute every step at arrival.”
Mars 5 successfully entered Mars orbit and returned images and measurements, but operated for only a short period before failing. Even a brief orbital mission provided useful experience in operating around Mars and sending data back to Earth. It became the clearest Soviet success of the 1973 launch set, though not a long-lived one.
Mars 6 reached Mars and began its descent sequence, but contact was lost just before landing. This outcome suggested that the spacecraft could reach the critical final phase, yet still struggled with the harsh conditions of entry, descent, and landing. The failure reinforced how difficult it was to build systems that survived the last minutes of a Mars landing attempt.
Soviet Mars probe program: launches, failures, and flybys (1960–1974)