The decade of Venus is almost upon us. With three upcoming Venus missions planned from NASA and the European Space Agency , we’re on the cusp of learning more about our neighboring planet than ever before.
However, fuel is also very heavy. And weight is money when it comes to rocket launches. The more fuel a spacecraft is carrying, the more expensive it will be to launch and the less allowance there will be for scientific instruments. A 15-month marathon When EnVision arrives at Venus, it will be orbiting at an altitude of 150,000 miles. And it needs to get all the way down to 300 miles above the surface to get the readings that the team wants. To do this, it will dip into the atmosphere thousands of times over a period of between 15 months and two years, gradually moving into the correct orbit.
The exact temperatures that the spacecraft will experience will depend on final design decisions, but it will be in the region of “maybe 200 or 300 degrees centigrade for the highest temperature,” Adrian Tighe, materials scientist for EnVision, said. There’s also the ultraviolet radiation from the sun that the spacecraft will have to handle. “It’s quite a harsh environment for the materials.”
The biggest concern is the spacecraft’s solar panels, because they are so exposed. The solar cells are covered in glass, which is resistant to atomic oxygen, but these are set into a substrate typically made of carbon fiber, which is susceptible to erosion. Another sensitive component is the thin foil used as insulation between the cell and the panel, called kapton. And there’s a thin foil connecting the different cells, which is sometimes made of silver — and that is sensitive too.
Atmospheric scientists are excited about the possibility of getting an up-close view of the planet’s upper atmosphere, which is rarely studied. Studying the upper atmosphere is hard, according to EnVision scientist Gabriella Gilli of the Instituto de Astrofísica de Andalucía in Spain, because it is so thin compared to the dense lower atmosphere. “It’s difficult to measure with remote sensing instruments.
Adjusting to conditions The observations collected during the aerobraking phase won’t only be of scientific interest though. They will also be fed back to the spacecraft team, who can adjust the way the maneuvers are being planned if, say, it turns out that the density in one part of the atmosphere is different from what was expected.