By Dr. Gary Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
This is the second article in a six-part series on the history of Venus space exploration and research, and the possibility of human colonization on Venus.
In the first part of this article series, I described how Venus space research got off to a rocky start in the 1960s. Only NASA’s Mariner 2 mission in 1962 fully achieved its intended objectives. The USSR achieved partial success with Venera 2 and Venera 3 in 1965 and 1966, respectively.
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USSR and US Had Better Success Collecting Venusian Data in the Late ‘60s and ‘70s
In 1967, the Soviets launched Venera 4, and this launch became the USSR’s first unqualified success in pursuit of Venusian research. Venera 4 successfully deployed a thermometer and a barometer in Venus’s atmosphere to collect data on temperature and pressure. In addition to temperature variations with altitude, the spacecraft’s barometer was able to determine that pressure on the surface is the equivalent of more than 22 Earth atmospheres.
The probe itself also descended into Venus’s atmosphere on a parachute, and it was able to return some data before running out of power. Unfortunately, the Soviets made the probe’s parachute too big. As a result, Venera 4’s batteries died before it reached its ultimate crush depth — the point at which the spacecraft would be crushed to the point of inoperability by the weight of the Venusian atmosphere above it.
Also in 1967, NASA launched Mariner 5 as a follow-up to Mariner 2. Mariner 5 flew within 4,000 kilometers of Venus and collected additional data on planetary temperatures.
It would be two more years before the Soviets would return to Venus with another mission. In 1969, they launched Venera 5 and 6, which made their way to Venus within a day of one another. This time, the Soviets learned their lesson from Venera 4 and downsized each spacecraft’s parachute to allow these two probes to send data home from deeper within Venus’s cloud cover.
Venera 5 and 6 were equipped with more detailed chemical analysis tools to better understand the nature of the Venusian atmosphere, which is mostly carbon dioxide. Both spacecraft lasted nearly an hour in their descents and were able to send back data the entire time until they were crushed.
In 1970, the USSR launched another follow-up mission, Venera 7. Like its predecessors, Venera 7 entered the atmosphere and descended by parachute.
This time, however, the probe was built to withstand the pressures of the atmosphere all the way to the Venusian surface. It was expected to take about an hour to make the full descent, but for unknown reasons, the probe landed in just over half that time. Mission controllers speculated that the parachute might have been damaged on the way down.
Nonetheless, Venera 7 was able to transmit for about 20 minutes after touchdown, making it the first-ever spacecraft to send back a signal from the surface of another planet. The lander confirmed previously gathered data about Venus’s extreme surface temperatures and pressures. A separate mission, Cosmos 359, was launched just a few days after Venera 7 in 1970, but it was unsuccessful due to another rocket failure.
USSR Continued to Learn from Its Spacecraft Construction Mistakes
In 1972, the Soviets launched Venera 8. Venera 8 was built to land on the surface like the prior Venera missions.
However, a cooling system was added to the probe’s hardware this time, so that the electronics could withstand the surface temperatures for a bit longer. As a result, Venera 8 survived on the surface of Venus for nearly a full hour.
In addition to temperature and pressure data, Venera 8 measured light levels in order to pave the way for future missions equipped with cameras. Like Venera 7, Venera 8 was followed a few days later by Cosmos 482, and it also failed just as Cosmos 359 did due to rocket failure.
NASA’s Mariner 10 Captured First Ultraviolet Images of Venus in 1974
In November 1973, NASA launched Mariner 10. In February 1974, the probe conducted a flyby of Venus on its way to its ultimate destination, Mercury. In the process, Mariner 10 captured the first-ever ultraviolet images of Venus.
Soviet Space Missions Became More Complex
In 1975, the Soviets launched the next major milestones in the successive Venus research: Venera 9 and 10. The two missions were designed to be much more complex than their predecessors.
Each spacecraft consisted of both an orbiter and a lander, and each lander was equipped with a camera. After successful touchdowns, both landers captured and sent back the first-ever images of the surface of another planet.
Unlike the first communications from prior landers, Venera 9 and 10 relayed their data transmissions back through their orbiter components, which then sent them to Earth. In addition to the relay function, the orbiters also collected their own data on the Venusian cloud cover and atmosphere as they circled the planet.
The landers ultimately touched down more than 2,000 kilometers (about 1,243 miles) apart on Venus. Consequently, researchers were able to collect images from very different locations on the Venusian surface for comparative reference.
NASA Conducts Further Probing of Venus with Pioneer Venus 1 and 2
Three years later in 1978, NASA returned to Venus for more science with the Pioneer Venus 1 and 2 missions. Pioneer Venus 1, like its Venera counterpart, consisted of an orbiter and a descent component. It was equipped with 17 different science instruments in total.
On the orbiter was radar-mapping technology, which allowed researchers to map the entire Venusian surface topography with a resolution of about 75 kilometers (46 miles). From this mapping, researchers found Venus to be a relatively smooth planet without many extreme changes in elevation.
The descent component of Pioneer Venus 1 was called a multiprobe. It actually consisted of five separate instruments that released from the orbiter and entered the atmosphere to collect different kinds of data.
Pioneer Venus 2 was similar in design, with a main spacecraft bus and a multiprobe consisting of four separate atmospheric instruments. This time, one of the probes descended by parachute to the surface, and it was able to continue transmitting data back to NASA for more than 60 minutes after touching down on the surface. Also, the Pioneer Venus missions were some of the first to detect and report thunder and lightning in the atmosphere on Venus.
The USSR would not be outdone, though. In that same year of 1978, they launched two more missions to keep pace with NASA’s Venus research efforts. In the next part of this article, I’ll review those missions and the continuation of Venus research into the 1980s.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.