Venera 1

Venera 1The 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.

Sagan: let’s terraform Venus

Carl SaganIn 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).

Mariner 1 launched and lost

Mariner 1NASA 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.

Mariner 2 launched

Mariner 2NASA 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.

Mariner 2 visits Venus

Mariner 2NASA’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.

Zond 1

Zond 1The 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.

Venera 3

Venera 1The 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.

Venera 4

Venera 1The 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.

Mariner 5 launched

Mariner 5A 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.

Mariner 5: return to Venus

Mariner 5Launched 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.

Venus Orbiter Imaging Radar

VOIRA 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.

Mariner 10 launched

Mariner 10The 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.

Mariner 10 visits Venus

Venus by Mariner 10The 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.

Venera 9: first pictures from another planet

VeneraThe 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.

Pioneer Venus Orbiter launched

Pioneer VenusNASA 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.

Pioneer Venus Multiprobe launched

Pioneer VenusTrailing 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.

Pioneer Venus: visit to a hot planet

Pioneer VenusJust 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.

Pioneer Venus completes its map… for now

VenusNASA’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.

Venera 14 lands on Venus

VenusThe 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.

New assignment for Pioneer Venus

Pioneer VenusHaving 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.

Vega 1 launched

Vega 1The 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.

Vega 2 launched

Vega 1Just 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.

Vega 1 visits Venus

Vega 1The 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.

Vega 2 visits Venus

Vega 1The landing module of the Vega 2 unmanned space probe successfully lands on Venus, gathering and analyzing soil samples and transmitting its findings back to Earth before the heat and atmospheric pressure destroy it within an hour. The terrain it lands on is found to be composed of rock resembling the surface of Earth’s moon. The Vega 2 “mothership” continues past Venus, en route to a rendezvous with Halley’s Comet.

Galileo at Venus

VenusNASA/JPL’s Galileo space probe – eventually bound for Jupiter – reaches the first destination on its looping “VEEGA” (Venus/Earth/Earth Gravity Assist) trajectory, the planet Venus. This flyby of Venus allows for testing of Galileo’s cameras and other science instruments, offering the first near-infrared views of the planet’s dense clouds, and the discovery that there is almost no water vapor in Venus’ thick carbon-dioxide atmosphere. The next “stop” for Galileo is Earth, mere months later.

Magellan arrives at Venus

MagellanLaunched via space shuttle in May 1989, the long-delayed Magellan space probe reaches the planet Venus after an unusually long voyage (15 months) and begins an orbital insertion maneuver. Where most missions to Venus have reached the planet in only a few months, Magellan has had to make do without the more powerful Centaur liquid-fueled booster stage, resulting in a journey of a year and three months. (The Centaur upper stage had been cancelled after the Challenger disaster because it was felt that carrying an additional liquid-fueled rocket in a shuttle cargo bay was too risky.) Magellan is placed into an elliptical orbit, completely circling Venus every three hours, where it will conduct high-resolution radar mapping of the surface at the closest point in its orbit, and transmitting the resulting data to Earth while furthest from Venus. The first phase of the mapping mission will last through 1991.

Magellan the mapmaker

VenusNASA’s Magellan space probe, orbiting the planet Venus, has completed a checkout phase and begins its primary mapping mission, intended to gather data of the Venusian surface as high resolution as one kilometer per pixel. Rather than using visible light – which would yield only images of Venus’ dense clouds – Magellan uses radar to map the planet’s blistering hot surface. Launched in May 1989 via space shuttle, Magellan will continue mapping the surface of Venus through May 1991.

Magellan: mapping Venus in stereo

VenusThe third phase of data gathering begins for NASA’s Magellan unmanned space probe, launched via space shuttle in 1989 and currently orbiting the heavily-clouded planet Venus. Using radar to peer through the planet’s dense clouds, Magellan has now mapped 96% of the planet’s surface, and will now spend much of the remainder of 1992 filling in details in regions it has missed, as well as re-scanning some regions of Venus stereoscopically, allowing for three-dimensional terrain reconstruction.

Magellan goes fourth at Venus

VenusNASA’s unmanned Magellan space probe, having completed three extensive campaigns of mapping the surface of Venus from orbit with cloud-penetrating radar, begins a fourth mission phase, this time sending constant engineering telemetry to Earth, where measurements of Doppler shift in the signal received allows Earthbound scientists to map the gravitational field of Venus. Magellan’s map-making days are over, having achieved a 98% complete map of the cloud-shrouded planet that it has been orbiting since 1990.

Farewell to Pioneer Venus

VenusThe Pioneer Venus Orbiter, launched into orbit around Venus in 1978 and now the only surviving component of the Pioneer Venus mission, enters the cloudy planet’s dense, toxic atmosphere and disintegrates, its fuel supply too exhausted to keep it in orbit any longer. Originally intended to orbit Venus for only a year, Pioneer Venus has survived, fully functional, for nearly 14 years in Venusian orbit, continuing to study the planet and taking readings not only Venus but such objects as Halley’s Comet.

Magellan tests aerobraking at Venus

MagellanTo increase the accuracy of its gravity map of the planet Venus, NASA’s unmanned space probe Magellan conducts the first experimental aerobraking maneuvers to alter the shape its orbit to a near-circular shape. By dipping Magellan into the upper layers of the Venusian atmosphere, the spacecraft is slowed and its orbit is changed, but it is kept far enough from the denser lower layers of the atmosphere to avoid re-entry. Aerobraking will become more commonly used by future space probes at the planet Mars.

Magellan tilts at Venusian windmills

MagellanNASA’s Magellan space probe, still orbiting Venus since 1990, enters a phase of slightly riskier experiments, dipping its solar panels into the upper reaches of the Venusian atmosphere and firing its reaction control engines to keep from spinning out of control. This allows for studies of the composition of Venus’ atmosphere, as well as studies of the vehicle’s behavior as it resists atmospheric friction. The results of the “windmill” experiment inform the design of future Mars probes which will need to aerobrake to slow down and enter the Martian atmosphere.

Farewell, Magellan!

Carpe AtmospherumNASA’s Magellan space probe, orbiting Venus since 1990, is retired by entering the atmosphere of the planet whose surface it has mapped. With its power systems exhibiting signs of age and wear, Magellan has been intentionally dropped into an orbit low enough to allow its destruction in Venus’ dense atmosphere. Launched in 1989 via space shuttle, Magellan mapped the planet’s surface with cloud-penetrating radar, covering 98% of the Venusian surface, at least 1/5 of it with stereoscopic imaging allowing for accurate 3-D reconstruction of Venus’ surface features.

Venus Express arrives

VenusThe European Space Agency’s Venus Express space probe – the first unmanned spacecraft to closely examine the second planet from the sun since the late 1970s – arrives at the planet to undertake a detailed study of the atmosphere, the unusually symmetrical cloud patterns of the planet’s north and south hemispheres, as well as observing the massive, hurricane-like vortices which remain over the poles. Venus Express also looks for the source of traces of sulphur dioxide in the Venusian atmosphere, which could be a sign that of active volcanoes on the surface.

AKATSUKI launched to Venus

AkatsukiThe Japanese space agency, JAXA, launches unmanned space probe AKATSUKI, known more formally as the Venus Climate Orbiter. The spacecraft is expected to reach Venus in seven months and take up orbit around that planet, where it will study Venus’ atmosphere in depth. “Akatsuki” translates to “Dawn”, but is referred to by its Japanese name to avoid confusion with NASA’s asteroid-belt-exploring Dawn spacecraft.

Missing Venus

Akatsuki at VenusJapan’s AKATSUKI unmanned space probe fires its thrusters to slow down enough to be captured into an orbit around Venus, a maneuver which will take place mostly in the planet’s shadow, out of communication with Earth. But when ground controllers reacquire communications with AKATSUKI, it is in safe mode, and not in its predicted orbit around Venus. The main orbital engine, damaged by overheating due to salt deposits on a fuel valve, fired for less than three minutes and cannot safely be fired again, leaving AKATSUKI into a solar orbit. Mission planners put AKATSUKI into a hibernation mode to preserve it for another opportunity to orbit Venus in 2015.

AKATSUKI’s second shot at Venus

Akatsuki at VenusJAXA, the Japanese space agency, announces its plans to put the unmanned AKATSUKI space probe into orbit around Venus. Originally launched in 2010, AKATSUKI failed to orbit the planet in December of that year due to a critical engine malfunction and instead fell into an orbit around the sun, but mission planners have devised a strategy to use its attitude control engines to slow it enough to be captured around Venus when it intersects the planet’s orbit again. AKATSUKI, more formally known as the Venus Climate Orbiter, is intended to study the atmosphere and weather of Venus, a mission it will begin in December if it can successfully enter orbit.