Carl Sagan once said that Venus is the most hell-like planet in our solar system. So when do we return? Astronomers on Monday reported the detection of a chemical in Venus’ acidic clouds, phosphine, which may be a possible sign of life. That has some planetary scientists eager to return to the second planet from the sun, especially those who feel that Venus has long been overlooked in favor of Mars and other destinations.
“If this planet is active and producing phosphine, and something is doing it in the atmosphere of Venus, then by God almighty, forget this nonsense about Mars,” said Paul Byrne, planetary scientist at Carolina State University. from North. “We need a lander, an orbiter, we need a program.”
Venus is not easy to visit. Its carbon dioxide-rich atmosphere is 90 times denser than ours, and surface temperatures average 800 degrees Fahrenheit. Its surface pressure is intense enough to crush some submarines.
But that hasn’t stopped human space programs from trying. About 40 robotic spacecraft launched by governments on Earth have attempted to visit Venus in one way or another. Below are highlights from previous trips to Venus, as well as prospects for a quick return to the planet to find out what’s happening in those clouds.
The many Soviet visitors to Venus
In 1961, the Soviet space program began trying to explore Venus. In the decades that followed, it fired dozens of spacecraft into the world sometimes known as Earth’s twin. While the Soviet exploration of Venus began with many misfires, the country became the first to land a spacecraft on another world and, shortly after, the first to take photos from the surface of another planet. Her engineering achievements were significant even by modern standards.
After seeing their first round of spacecraft sent into the atmosphere crushed like cans, the Soviets realized just how extreme the pressure on Venus was. This trial and error led to the construction of a 5-ton metal spacecraft built to withstand, even for just an hour, the immense surface pressures.
Venera 4 in 1967 became the first spacecraft to measure the atmosphere of another planet, detecting large amounts of carbon dioxide that cause the incessant Venusian greenhouse effect.
Then, in 1975, the country’s Venera 9 probe became the first to image the surface of another planet. The world officially met Venus. The images it sent and subsequent missions revealed a planet that truly was like no other: cracked terrain under a dilute, hazy neon green light. The planet we thought might have been covered in oceans and similar to ours was instead a strange world with poisonous rain.
Subsequent missions in the Venera series in the 1980s gave scientists a better understanding of the planet’s geological processes. Venera 11 and 12 detected large amounts of lightning and thunder as they traveled to the surface. Venera 13 and 14 were equipped with microphones that documented the sounds of their descent to the surface, making them the first spacecraft to record audio from another planet.
In 1985, the Soviet Union concluded its Venus encounters with the twin Vega spacecraft, each of which launched large balloons loaded with science instruments, demonstrating the potential for probes that could float in the planet’s clouds.
The slower pace of the Soviet space program towards the end of the Cold War halted launches to Venus. While the Russian space program has discussed future exploration of Venus, its concepts have not moved off the drawing board.
NASA also kept an eye on Venus
While Mars has always seemed the apple of the eye of American space planners, the Mariner and Pioneer programs of the 1960s and 1970s made time for Venus. Mariner 2 was the first American spacecraft to reach Venus, in 1962. It determined that temperatures were cooler in the clouds, but extremely hot on the surface.
In 1978, the Pioneer missions gave American researchers a closer look. The former of the two orbited the planet for nearly 14 years, revealing much about the mysterious Venusian atmosphere. He also observed that the surface was smoother than Earth’s and that Venus had little or no magnetic field. A second Pioneer mission sent several probes into the atmosphere of Venus, returning information about the structure of the clouds and radar readings of the surface.
NASA’s Magellan entered orbit in 1990 and spent four years mapping the surface and looking for evidence of plate tectonics. It found that almost 85% of the surface was covered by ancient lava flows, indicating significant past and possible present volcanic activity.
It was also the last of the American visitors, although several NASA spacecraft have used Venus as a slingshot while en route to other destinations.
Other Visitors to Venus
Venus Express was launched by the European Space Agency in 2005. It orbited the planet for eight years and observed that it could still have been geologically active. The planet’s only guest from Earth at the moment is Akatsuki, which was launched by Japan in 2010. The probe missed its encounter with Venus when its engine failed to start as it headed into orbit. By 2015, the mission managers had managed to lead him on a course to orbit and study the planet.
Since then, it has transformed the way scientists view our cloudy twin. In its study of the physics of Venus’ dense cloud layers, the mission has revealed disturbances in the planet’s winds known as gravity waves, as well as equatorial jet streams in its atmosphere.
Who is the next one?
Many missions back to Venus have been proposed, and some space agencies have declared ambitions to visit the planet. But it is difficult to say if any will make the trip.
India’s space agency has proposed a mission called Shukrayaan-1, which will orbit the planet and focus primarily on the chemistry of the atmosphere.
Peter Beck, the founder of Rocket Lab, a New Zealand-founded private company that has launched about a dozen rockets into space, recently talked about sending a small satellite to the planet. NASA has considered several Venus proposals in the past decade, including two in 2017 that were finalists for NASA’s Discovery program, which had previously sent explorers to the moon, Mars, Mercury, and other destinations. But instead, the agency selected a couple of asteroid missions.
Also in 2017, for the largest and most expensive New Frontiers competition, NASA considered a Venus mission called Venus In Situ Composition Investigations, or VICI, that sought to put two landers on the planet’s surface. It was overlooked for Dragonfly, which will send a plutonium-powered drone to fly on Titan, Saturn’s largest moon.
NASA, however, provided money for some of the technologies that VICI would need. And the proponents of Venus may have a new advocate within NASA. Lori S. Glaze, VICI Principal Investigator, is now director of NASA’s planetary science division.
The agency will have another opportunity to choose a Venus mission for funding in the next round of its Discovery program.
Two Venus spacecraft, named DAVINCI + and VERITAS, compete against proposed missions to Neptune’s moon Triton or Jupiter’s volcanic moon Io. NASA can select two of the four finalists. And there could be other possibilities for visitors to Venus.
“We must also recognize that Venus is a planetary destination that we can reach with smaller missions,” said Thomas Zurbuchen, director of NASA’s science mission directorate.
Shannon Stirone c.2020 The New York Times Company
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