Overheated by the gases present in the atmosphere and by the greenhouse effect, the climate of Venus it was a time similar to that terrestrial. In addition to what has been discovered in recent years on the conformation of the soil, Venus could also have a crust formed by huge plaques of subduction, as well as the Earth, that is areas in which a crust plate of the planet slips below a second less dense plate.
There are therefore some analogies between the two planets, and there is a mission that aims to explore Venus to obtain data to be used also for the understanding of any other planet or exoplanet.
Come back to understand us more
Planetary scientist Sue Smrekar, in her office at NASA’s Jet Propulsion Laboratory in California, is moving to make a new mission on Venus a reality. In the following image you can appreciate a representation of the surface of Venus from 30 years ago, made in 3D via data collected by the Magellan spacecraft, a reminder of how much time has passed since an American mission orbited the planet.
The image reveals an infernal landscape: a young surface with more volcanoes than any other body in the solar system, gigantic fractures, high mountain ranges and temperatures warm enough to liquefy the lead.
Venus represents a good comparison term with Earth. Scientists believe that they both started their “life” with the same composition, the same amount of water and carbon dioxide, and then followed two completely different evolutions. Smrekar works with the Venus Exploration Analysis Group (VEXAG), a coalition of scientists and engineers studying plans to revisit the planet that Magellan mapped many decades ago.
Although their approaches are different, the group agrees that Venus could tell us something extremely important for our planet: what happened to its overheated climate and how it can be useful for understanding the development of life on Earth?
In the image below, one click which portrays the Magellan spacecraft, a great pioneer of thespace exploration.
A demanding mission
Venus is not the closest planet to the Sun, but it is the warmest in our solar system. Characterized by extremely high temperatures (480 degrees Celsius), sulphurous corrosive clouds and an atmosphere 90 times denser than Earth’slanding with a spacecraft would be incredibly challenging. Of the nine Soviet probes that made the venture, none managed to survive for longer than 127 minutes.
From the relative safety of space, an orbiter could use radar and infrared spectroscopy to peer beyond layers of clouds, measure soil irregularities that may vary over time and determine whether the soil is moving or not. In the image below, a scan of the venus surface obtained during the Magellan mission 30 years ago.
A probe could search indicators due to the presence of water, volcanic activity and other climatic, geological or environmental factors that they may have shaped the planet in the millions of years ago. By studying Venus, scientists were able to learn a lot about exoplanets, as well as about the past, present and possible future of ours. The following video summarizes some highlights of what has been said so far.
In search of VERITAS
Dr. Smrekar is working on an orbital mission proposal called VERITAS and believes that Venus does not have a true tectonic activity like that of Earth. However, it sees possible hints of subduction, or the movement by which two portions of the outermost part of the mantle of Venus converge with one plate that flows under the other. The truth is that very little is known about the composition of the surface of Venus, but it is believed that there are continents, such as on Earth, that may have formed through the subduction that occurred millions of years ago. However, we do not yet have enough data to establish it concretely.
Having answers to these questions would not only improve our understanding of why Venus and Earth are so different, but could narrow the conditions that scientists need to find an Earth-like planet elsewhere.
Balloons
Orbiters aren’t the only way to study Venus from above. JPL engineers Attila Komjathy is Siddharth Krishnamoorthy they theorized a fleet of hot air balloons capable of ride the winds storm in the upper levels of the atmosphere of Venus, where temperatures are close to those land.
Currently there is no effective mission funded to fly air balloons over Venus, the idea is still excellent because the atmosphere is inhospitable, but it also allows you to take advantage of in a much more favorable environment than the ground.
This environment allows the sensors to last long enough to cover a period of time useful for collecting data on temperature, pressure, density and variations in these quantities. And even the “earthquakes”.
The team would equip the balloons with seismometers sensitive enough to detect earthquakes on the planet below, even if they don’t rest directly on the surface. Like? On Earth, when the earth trembles, that movement also disturbs the atmosphere thus generating very weak waves.
Krishnamoorthy and Komjathy have shown that this phenomenon can be detected using particular aerostatic balloons, which measure the weak signals which originated as jerking movements and which have turned into extremely weak waves.
Air earthquakes
In the dense atmosphere of Venus, a jolting movement of the earth would return even stronger and clearer results, since the mass of gas that composes it would move with much more consistency, precisely because of the greater density of the fluid.
Moreover, one cannot help noticing a similarity with the cloud conformations present here on Earth; look at the following image: the protagonist of the photo is Venus.
To obtain those seismic data, however, a “hot air balloon” mission would have to face the strong winds that rage in the atmosphere of Venus. The “ideal balloon”, so called by the Venus Exploration Analysis Group, may be able to stabilize its motion in at least one direction.
Krishnamoorthy and Komjathy’s team has not yet reached this level of control, but they have proposed a middle ground: having balloons unable to control their motion but capable of exploiting the winds on the planet to obtain a constant speed, then returning the data collected to an operational orbiter just beyond the atmosphere of Venus.
You have to land
Among the many challenges that a lander must face in approaching landing on Venus, clouds represent one of the most insidious: for example, without sunlight the amount of energy stored in the lander’s batteries would be severely limited. But the planet is too hot to exploit other energy sources. Any batteries should then be insulated in a workmanlike manner because with high temperatures they would instantly overheat.
By default, the duration of a landing mission is interrupted by the spacecraft electronics which starts to fail after a few hours. In addition, the amount of energy required to operate a refrigeration system capable of protecting a spacecraft would require more batteries than a lander could carry.
There NASA (who recently successfully conducted a test on a tall tank like a building) is interested in developing technology capable of surviving days or even weeks in extreme environments. Although all previous projects have failed to pass the approval stages, many of the proposed ideas have flowed into the implementation of a new drilling system and heat resistant sampling that could take Venusian soil samples for analysis in terrestrial laboratories.
Everything should obviously be protected by heat shields to cope with the conditions of the planet, characterized by an atmosphere formed by almost 100% carbon dioxide. Some tests have been conducted with some small success, and with each test passed, scientists bring humanity closer and further towards the effective exploration of this inhospitable planet.
Image credits: NASA / JPL-Caltech
