During the infancy of the Space Age the only two nations on the world who could even think about mounting a mission to explore Venus were the United States and the now extinct Soviet Union. Of the two nations, the Soviet Union was the nation to dedicate the most time, money, and spacecraft to the early exploration of Venus. Between the years of 1961 and 1984 the Soviet Union launched 18 missions at the "tiny" fireball while the United States launched a mere four in the same time frame and a fifth one in 1989 before a 16 year hiatus where no nation launched a mission to the planet.
The First Flybies
Although the Soviets were the first to launch a mission toward Venus in 1961, the United States' Mariner series of spacecraft were actually the first to come even close to the planet when a flyby occurred during 1962. Two more Mariner flybys would occur during 1967 and 1973 but little, if anything was learned of the planet by these missions. Following the failure of its first three spacecraft launched at Venus, the Soviets' Venera 4 arrived into Venutian orbit on October 18, 1967; a little over five years after its American counterpart streaked by.
The Venera Chronicles
Venera 4 released two thermometers, a barometer, radio altimeter, atmospheric density gauge, 11 gas analyzers, and tow radio transmitters into Venus' atmosphere. The main bus of the spacecraft carried a magnetometer, cosmic ray detector, hydrogen and oxygen indicators, and charged particle traps which contributed to a stockpile of data transmitted back to the motherland.
After a short stay in orbit of the blazing planet, Venera 4 entered the Venutian atmosphere, deployed parachutes and made it to within 24.96 kilometers of the surface before contact with the adventuring spacecraft was lost forever. Its immediate follower; Venera 5; floated in the atmosphere for an impressive 53 minutes before contact was lost with it in 1969 where it carried most of the same instruments as its predecessor.
On December 17, 1970 Venera 7 entered the Venutian atmosphere on its way to making history as the first man-made object to return data after landing on another planet. It took the capsule 35 minutes to float its way down to the surface where it transmitted for 23 minutes before falling to the oppressive temperatures there. Venera 8 recorded a surface temperature of 470 degrees Celsius and 1 kilometer visibility on the surface of Venus where it lasted an amazing 50 minutes and 11 seconds prior to collapsing beneath the enormous heat and pressure strains of the hostile planet.
In 1975 the Soviets launched Venera 9 on a mission that would once again put them into the history books. Their newest rendition of the Venera series was sent to Venus to take surface readings and study the cloud and atmospheric features of the planet in far greater detail than the previous 5 successful missions to the planet. Venera 9 outperformed all expectations while recording a surface temperature of 485 degrees Celsius and lasting an impressive 53 minutes on the hostile surface.
Venera 9's claim to fame is that it sent back the first photographs of the surface of this hellish planet and set the stage for Venera 10 which arrived shortly after Venera 9 succumbed to the elements. As a matter of fact Venera 10 outlasted its predecessor on the surface by 12 minutes, recording a wind speed of 3.5 meters per second and transmitting back television photography of apparent lava-formed rocks to waiting Soviet scientists.
The next two Venera spacecraft were plagued by instrument failure but were able to beat the previous surface life times dramatically as Venera 11 lasted 95 minutes and Venera 12 lasted 110 minutes. Where these two were duds, Venera 13 through 16 proved their worth with a combined surface time of 184 minutes, first ever atmospheric pressure readings, first ever soil sample analysis, and the first maps of the Venutian surface. All in all the Soviet exploration of Venus proved to be extremely fruitful and provided a significant portion of the shelves of data scattered across the globe today on this fiery planet.
Soviet Round Two Falls Short
The Soviets continued their Venutian surface studies with a new line of spacecraft in 1984 known as Vega 1 and 2 but these missions were mostly forgotten in time because the American built Pioneer Venus and the promised Magellan spacecraft were rocketing their way into the spotlight. Pioneer Venus for instance was launched on May 20, 1978 and reached orbit on December 4th of the same year with a payload of 17 instruments.
Enter Pioneer Venus and Magellan
As the success of the Venera program increased, Pioneer Venus quietly took its readings of Venus and eventually became the only operational spacecraft on or around the planet until the arrival of Magellan in 1989. Pioneer Venus' biggest claim to fame is that it holds the record for longest mission around the planet as it remained operational until May of 1992 for a grand total of thirteen and a half years around the terrestrial fireball we know as Venus.
On May 4, 1989 the first interplanetary spacecraft launched from a Space Shuttle and the first American interplanetary mission since 1978; Magellan; was released by Atlantis' remote manipulator arm into Earth orbit where it would later rocket off on its way towards the planet on fire. The spacecraft was designed to produce the first high-resolution images of the surface of Venus by a team from NASA, the Jet Propulsion Laboratory, Martin Marietta, and Hughes Aircraft Company.
The primary objectives of the mission were to map at least seventy percent of the Venutian surface, take surface altitude readings, take temperature readings utilizing radiometry, and chart the distribution of Venus' gravity field. In order to complete these tasks Magellan was put into a highly elliptical orbit which allowed it to map Venus at perigee and transmit data to Earth near apogee.
In an effort to conserve money for this vital mission the team built this ten-sided spacecraft out of left-over and back-up parts from previous spacecraft such as Voyager, Galileo, and Ulysses. Incorporated into the spacecraft were high, medium, and low gain antennas as well as a radar altimeter and reaction wheels which were utilized for attitude control. Magellan possessed two solar panels and was covered in thermal blankets and heat-reflecting inorganic paint combined with louvers to dissipate heat from the primary instruments; the synthetic aperture radar and the radar altimeter. A trio of systems provided attitude determination and stabilization for Magellan; the reaction wheels, sun-sensors, and small thrusters.
This impressive piece of engineering performed well above expectations; mapping ninety-five percent of the surface of Venus with images better than any of Earth at the time. This single mission gathered more data than in all other NASA exploratory mission combined but facing major budget constraints in 1993, the American space agency pulled the plug on Magellan and its exploration of Venus to date in October of 1994. Since then the only spacecraft actually exploring Venus was the European Space Agency's "Venus Express" mission that was launched in 2005.