Venus, often called Earth’s “evil twin,” formed closer to the Sun and has since evolved quite differently from our own planet. It has a “runaway” greenhouse effect (meaning the heat is completely trapped), a dense carbon dioxide-rich atmosphere, no magnetic field, and a surface hot enough to melt lead.
Several unmanned science missions will study how and why this happened over the next decade. But now some scientists want to send a crewed mission there for a flight as well. Is a good idea;
With a slightly smaller diameter than Earth, Venus orbits closer to the Sun. This means that any water on the surface would have evaporated shortly after it formed, starting its greenhouse effect. Early and ongoing volcanic eruptions created lava plains and increased carbon dioxide in the atmosphere – starting the greenhouse effect, which raised the temperature from just above Earth to its current high of 475°C.
While Venus’ year is shorter than ours (225 days), its rotation is very slow (243 days) and “retrograde” – the opposite to Earth. The slow rotation is associated with a lack of magnetic field, resulting in the continued loss of the atmosphere. Venus’ atmosphere “hyper-rotates” faster than the planet itself. Images from several missions show V-shaped cloud patterns made up of sulfuric acid droplets.
Despite the harsh conditions, some scientists have hypothesized that the clouds of Venus may at certain altitudes harbor habitable conditions. Recent measurements apparently showing phosphine – a possible sign of life as it is constantly produced by microbes on Earth – in the clouds of Venus have been hotly debated. Clearly, we need more measurements and exploration to find where it comes from.
What we know about Venus so far has been gathered from many previous probes. In 1970-82, for example, the Soviet Venera 7-14 probes were able to land on the hard surface of Venus, survive for up to two hours, and send back images and data. But there are remaining questions about how Venus evolved so differently from Earth, which are also important for understanding that planets orbiting other stars might harbor life.
The next decade promises to be a bonus for Venus scientists. In 2021, Nasa selected two missions, Veritas and DaVinci+, to launch in 2028-30. The European Space Agency has selected EnVision for launch in the early 2030s. These are complementary uncrewed missions that will give us a deeper understanding of the environment and evolution of Venus.
Craters on Venus as seen by NASA’s Magellan probe. Image credit: NASA/JPL
Veritas will map the surface of Venus to determine its geological history, rock composition and the importance of early water. DaVinci+ includes an orbiter and a small probe that will descend into the atmosphere and measure its composition, study the planet’s formation and evolution, and determine whether it ever had an ocean. EnVision will study the planet’s surface, subsurface and atmospheric trace gases. It will use radar to map the surface with better resolution than ever before.
India is also planning an uncrewed mission, Shukrayaan-1, and Russia has proposed Venera-D.
Do we need crewed flights?
The idea of a manned flight to Venus was proposed in the late 1960s and involved using an Apollo capsule to fly people around the planet. But that idea ended when Apollo ended. Now, the Artemis project to fly around the Moon and other ideas for crewed missions have led to the idea being repeated, most recently in magazines and at a recent meeting of the International Astronautical Federation, an advocacy group, in September 2022.
The idea would be to fly a crewed spacecraft around Venus and return to Earth. This would allow scientists to test deep space techniques, such as how to operate a crewed mission with significant time delays when communicating with Earth. It could therefore prepare us for a more complex manned mission to Mars. However, the crew would not do any landing or real atmosphere research on Venus – the conditions are too harsh.
Researchers supporting this idea argue that you could also use Venus’ gravity to alter the spacecraft’s course for Mars, which could save time and energy compared to going directly from Earth to Mars . That’s because the latter option would require the two planets’ orbits to align, meaning you’d have to wait for the right moment both on the way there and back. However, since a manned mission to Mars would be extremely complex, going directly from Earth to Mars would keep the plans simpler.
Sending humans to a planet that can host living organisms also won’t make it any easier to find them. It’s dangerous – we might end up polluting the atmosphere before we discover any life. The best way to look for biochemical signs of life is with unmanned probes. There would also be significant thermal challenges and higher radiation from solar flares due to the greater proximity to the Sun.
And, unfortunately, with a flyby mission like this, only a few hours of data would be possible for the incoming and outgoing orbits. It would be a very expensive undertaking, which would no doubt produce stunning images and useful additional data. However, this would add little to the detailed and much larger bespoke studies currently planned. Therefore, I believe that the possibility of a manned mission to Venus is very unlikely.
There have also been conceptual, more far-fetched studies – including sending manned aircraft to hover in the atmosphere of Venus, rather than simply flying from there. This is a nice idea, which may achieve more science than a flight, but it remains a distant and unrealistic idea for now.
Currently, we only conduct manned exploration in low Earth orbit. Project Artemis, however, aims to fly humans around the Moon and build a station, called Gateway, in lunar orbit. This is designed to do science, enable crew landings on the Moon and most importantly test deep space techniques such as refueling and operating in a remote environment that could in the long run help us get to Mars without training on Venus .
Andrew Coates, Professor of Physics, Associate Director (Solar System) at the Mullard Space Science Laboratory, UCL
This article is republished from The Conversation under a Creative Commons license. Read the original article.