The Soviet Union launches Venera 1, the first interplanetary space probe. Bound for Venus, Venera 1 returns measurements and observations taken during its three-month flight, but loses contact with ground controllers just as it makes its closest approach to Venus at a distance of 62,000 miles from the planet. It falls into an orbit around the sun after falling silent.
In the journal Science, Carl Sagan proposes an audacious scheme to alter the chemistry of the atmosphere of Venus, making it habitable for humans. His plan involves depositing algae colonies into the planet’s clouds to begin converting the planet’s carbon dioxide into breathable oxygen, and the idea is years ahead of its time (and will later prove to be impractical when more direct studies are made of the Venusian atmosphere).
NASA launches the JPL-built unmanned space probe Mariner 1, the first of two identical spacecraft intended to study the planet Venus. Mariner 1’s mission, however, is cut short before it even leaves Earth’s atmosphere: a communication loss between its Atlas-Agena booster rocket and ground-based control systems sends the rocket off course. Fearing that it might tumble into the Atlantic Ocean’s heavily traveled shipping lanes, NASA orders the vehicle to self-destruct in mid-air. Many later accounts lay the blame at an error in the code loaded into the rocket’s on-board guidance computer. Mariner 1’s mission objectives are transferred to its identical twin, Mariner 2, due to be launched in just over a month.
NASA launches its first interplanetary spacecraft, the unmanned space probe Mariner 2, en route to Venus. During its three-month trip from Earth to Venus, Mariner 2 takes measurements of solar wind, charged particles, and an experiment is included to measure the amount of dust and micrometeoroids between the two planets. The probe briefly loses attitude control several times in flight, but regains proper orientation in each instance.
NASA’s unmanned Mariner 2 probe is the first unmanned spacecraft to successfully reach and take measuresments of another planet in the solar system. Passing by Venus at a distance of 25,000 miles, Mariner 2 detects a cool atmosphere with a blistering hot surface underneath it – quickly dispelling any hopes of finding life there. Mariner 2 isn’t equipped with any cameras, which is just as well: unless any cameras had ultraviolet filters, they would have seen nothing but featureless clouds at Venus. Mariner 2 continues on into a solar orbit, shutting down early in 1963.
The Soviet Union launches the space probe Zond 1 toward Venus, a more sophisticated version of the Venera 1 vehicle sent to that planet in 1961. Thanks to an electrical short within the Zond space probe, ground controllers lose all contact a month after it leaves Earth; by the time it swings past Venus at over 60,000 miles months later, Zond 1 has shut down completely.
The Soviet Venera 2 space probe is launched toward Venus, and for the first time cameras are placed aboard a vehicle bound for that planet. Venera 2 will eventually pass within 14,000 miles of its target, but electrical failures silence the space probe and its instruments long before the flyby.
The Soviet Union launches Venera 3, its third attempt to send a spacecraft to Venus. Intended to land on the surface of what is still thought of as a near-twin of Earth, Venera 3’s landing capsule does indeed enter the Venusian atmosphere in March 1966, though the capsule loses contact with Earth and goes silent before ever hitting the surface of Venus. Venera 3 may be the first human-made object ever to arrive on another planet, but no telemetry exists to prove that it arrived in one piece.
The Soviet Union launches Venera 4, a space probe dispatched to the planet Venus. Venera 4 is equipped with a landing probe which it deposits into the planet’s dense atmosphere in October, and the probe’s findings stun scientists on Earth who had long considered Venus a near-twin of Earth: the atmosphere is predominantly carbon dioxide, with minimal oxygen and a pressure nearly 100 times Earth’s atmospheric pressure at sea level. The temperature within the Venusian atmosphere is found to soar past 800 degrees Fahrenheit, presenting a challenge for designers of the next round of vehicles to visit the planet. The Venera 4 landing probe is not equipped with cameras, and contact is lost with it before contact is made with the ground.
A near-identical twin of NASA/JPL’s unmanned Mariner 4 Mars probe, Mariner 5 lifts off en route to the planet Venus. Though the space probe’s architecture is similar to that of Mariner 4, Mariner 5 is modified to include solar shades to keep parts of the spacecraft cool, a problem which doesn’t exist at Mars. Mariner 5 takes almost exactly four months to reach Venus.
Launched four months before, NASA/JPL’s unmanned Mariner 5 space probe reaches the planet Venus. With its cameras removed to make way for other instrumentation, Mariner 5 provides valuable data on the makeup of the Venusian atmosphere and the probable conditions on the surface, corroborating what the Soviet Union’s successful landing of Venera 4 had found: a planet whose dense atmosphere traps heat and carbon dioxide, resulting in oven-like temperatures and ground-level pressures. NASA attempts to keep Mariner 5 functioning months after its flyby of Venus for tandem measurements of solar wind with Mariner 4, which has now passed beyond Martian orbit, but contact cannot be reliably maintained with Mariner 5 long enough to conduct the experiment.
A working group of scientists and engineers at NASA submit an official proposal for a spacecraft using synthetic aperture radar to map the surface of the planet Venus. Conceived as a mission that could be launched from a Titan IIIe or from the space shuttle, both of which still exist only on the drawing board, Venus Orbiter Imaging Radar (or VOIR) is designed to offer extensive mapping of Venus at a resolution much better than the coarse resolution of radar signals originating from Earth-based radio astronomy facilities such as Arecibo, along with such cutting-edge technologies as stereoscopic imaging and solar electric propulsion. Work on this mission will continue through the early 1980s, at which point it is cancelled by NASA and replaced by a cheaper mission intended to achieve the same goals, Magellan.
The first unmanned space probe to use a gravity assist maneuver to get from one planet to another in a reduced amount of time, Mariner 10 is lauched on a course for the planet Venus, where a carefully planned trajectory allows it to take pictures and measurements at that planet before using Venus’ gravity to fling Mariner 10 inward toward Mercury, allowing it to reach two planets in under two months. It will be the first space probe to visit Mercury.
The unmanned Mariner 10 space probe swings past the planet Venus at a distance of less than 4,000 miles, its cameras capturing a completely opaque sphere whose clouds reveal no surface. But when viewed through ultraviolet filters, Venus suddenly reveals an immense amount of atmospheric detail. Mariner 10’s UV views of Venus are the best images available until the dual Pioneer Venus mission of the late 1970s; meanwhile, Mariner 10 speeds past the planet en route to Mercury.
The Soviet Venera 9 unmanned space probe touches down on the surface of Venus, the first spacecraft to soft-land on another planet and send back pictures. With atmospheric pressure measured at almost 100 times Earth sea level pressure, and temperatures over 900 degrees Fahrenheit, Venera 9 manages to stay intact for barely an hour, sending back a single panoramic picture of Venus before the environment overcomes its systems.
Launched less than a week after history-making sister ship Venera 9, the unmanned Soviet space probe Venera 10 lands on Venus mere days after its twin, and experiences similar system failures due to the harsh environment on the planet. Venera 10’s landing site – captured in a single picture – shows strong evidence of past lava flows.
NASA launches the 1,100 pound Pioneer Venus Orbiter, designed to orbit Venus for a year to study the planet’s atmosphere and its interaction with other space phenomena. Though launched separately, the two Pioneer Venus spacecraft will arrive at Venus within days of one another in December 1978. The Orbiter takes radar observations of the cloud-shrouded planet, from which the first surface map of Venus is derived. As with many other unmanned NASA spacecraft designed for relatively short-duration missions, the Pioneer Venus Orbiter outlives its design lifespan, staying fully functional into the 1990s and eventually becoming the only American spacecraft to view Halley’s Comet in 1986.
Trailing its supporting orbiter by several months, the Pioneer Venus Multiprobe – also known as Pioneer 13 – lifts off en route to deposit its payload of four atmospheric entry probes designed to measure the planet’s inhospitable, poisonous atmosphere. Following the launch of those probes, the Multiprobe carrier vehicle will then enter the atmosphere of Venus itself and take measurements, burning up before it ever reaches the surface.
Just five days after the arrival of the Pioneer Venus Orbiter, the Pioneer Venus Multiprobe arrives at Venus, having already deployed its payload of four atmospheric penetration probes on their own trajectories to plunge through the planet’s dense atmosphere at different latitudes. Only one of these probes survives impact, transmitting for an hour afterward. The Multiprobe “bus” spacecraft, having relayed the smaller probes’ readings to Earth, then follows suit, plunging into the atmosphere and disintegrating before it can hit the surface. The Pioneer Venus Orbiter remains at Venus into the 1990s.
NASA’s unmanned Pioneer Venus Orbiter completes its radar mapping survey of the planet Venus, having used radar to create the first-ever topographical map of that world, which is usually hidden behind a thick, toxic cloud deck. Launched in 1978, Pioneer Venus Orbiter is the only surviving component of the two-vehicle Pioneer Venus mission, but with its solar arrays still gathering adequate power and all of its instruments still functioning well, the orbiter is not deactivated or deorbited at this time; future tasks will be found for it in the years ahead.
The Soviet Union’s unmanned Venera 14 space probe successfully lands on the planet Venus, its landing module enduring almost an hour in temperatures of nearly 900 degrees Fahrenheit and air pressure nearly 100 times that experienced at sea level on Earth. A soil sampling experiment is thwarted by an unforseen problem, namely the lens cap of Venera 14’s camera popping off and landing precisely where its sampling arm was designed to gather Venusian soil for testing.
Having received new orders from NASA, the still-functional Pioneer Venus Orbiter – launched in 1978 and in a high, looping orbit over Venus since it ceased active observations of the planet in 1981 – turns its instruments in the direction of Comet Encke, which is currently passing through the inner solar system. Rather than its cameras, the orbiter’s ultraviolet spectrometer is trained on the comet as Earth-based researchers try to determine the composition and rotational speed of Encke’s nucleus. The Pioneer Venus Orbiter will continue to observe other comets through the late 1980s.
The unmanned Vega 1 space probe is launched by the Soviet Union on a dual mission to drop off a lander at Venus and then to intercept Halley’s Comet in 1986. Derived from the USSR’s earlier Venera Venus landers, Vega will test a refined landing system for landing on Venus by balloon, and will then join an international fleet of unmanned spacecraft attempting to take advantage of Halley’s visit to the inner solar system in late 1985 and early 1986.
Just days after its twin lifts off, the unmanned Vega 2 space probe is launched by the Soviet Union on a dual mission to drop off a lander at Venus and then to intercept Halley’s Comet in 1986. Derived from the USSR’s earlier Venera Venus landers, Vega 2 will test a refined landing system for landing on Venus by balloon, and will then join an international fleet of unmanned spacecraft attempting to take advantage of Halley’s visit to the inner solar system in late 1985 and early 1986.
The landing module of the Vega 1 unmanned space probe arrives at the planet Venus, though some of its on-board experiment packages activate during descent, rather than activating after contact with the surface, and little data is returned. Thanks to a gravity assist from a close flyby of Venus, the Vega 1 “mothership” continues past the planet toward a 1986 rendezvous with Halley’s Comet.