Venus is considered Earth’s sister planet because they are roughly the same size and have similar compositions. But that’s where the similarities end. Once scientists got a close look at Venus, they were greeted by a scorching hellscape of sulfuric acid clouds. The European Space Agency (ESA) is planning a new mission to Venus, where its EnVision spacecraft could conduct detailed science never before possible. First, engineers must figure out how to keep the spacecraft from blowing to pieces as it descends through the planet’s wild atmosphere. ESA announced the selection of EnVision last year and in recent days, provided an update on the design and construction of the probe. The plan is for EnVision to perform an aerobraking maneuver in Venus’ orbit, allowing it to gradually lower its orbit as it sweeps the surface. The agency has experience with this process from the Trace Gas Orbiter (TGO), as well as Venus Express. In the latter case, ESA only attempted aerobraking at the end of the mission in 2014, and it did burn up in the atmosphere. With EnVision, ESA needs to surf the corrosive soup attached to Venus before getting down to science. Specimens for simulated air brake tests. Venus’s atmosphere is 92 times denser than Earth’s, consists almost entirely of carbon dioxide, and probably does not support life. Crushing pressure is complemented by temperatures reaching 864 degrees Fahrenheit (462 degrees Celsius). For the record, that’s several hundred degrees above the melting point of lead. This is what makes studying Venus up close so difficult, but EnVision is designed specifically for these conditions. EnVision will likely launch in the early 2030s on an Ariane 6 rocket. ESA says it may not have enough mass to provide orbital fuel to lower its orbit, so it will rely on aerobraking. The mission will launch into a very high orbit at 250,000 kilometers (155,000 miles) and through successive passes through the atmosphere, will drop to a 500-kilometer (310-mile) polar orbit for scientific operations — no surface landing. ESA plans to take it slow with EnVision. Because heat is produced as a cube of speed, it will spend about twice as long slowing down as TGO. Engineers are also hard at work testing different air brake materials. They have extreme temperatures to contend with, and Venus’ atmosphere is also high in reactive atomic oxygen. Fortunately, ESA has a facility that can produce atomic oxygen at energy levels equivalent to orbital velocity. They test materials for insulation, antennas, star tracker elements and more. These materials must resist corrosion while also maintaining their optical properties, which ensures that the probe’s sensitive instruments work after it reaches its intended orbit. The team expects to have the results of this trial by the end of this year. When EnVision settles into its final orbit, it will map the planet in greater detail than ever before. Scientists hope that by studying Venus, which may be the victim of an unseen greenhouse effect, we could gain insights into what is happening on Earth. Read now:
