When a spacecraft has limited access to fuel, it becomes necessary to find a way out. That’s why EnVision mission engineers plan to use Venus’s atmosphere to perform what’s called aerodynamic braking.
The objective of the mission organized by the European Space Agency is to capture high-resolution optical, spectroscopic and radar images of the planet’s surface. First, however, you have to slow down, which will help the local atmosphere. Thanks to him, the ship will slow down and then lower its orbit. In total, over the course of two years, it will make thousands of times through the atmosphere of Venus.
The spacecraft will be launched into the orbit of Venus at a very high altitude of about 250 thousand km, and then we must descend into a polar orbit of 500 km for scientific operations. Flying the Ariane 62, we can’t afford all the extra fuel needed to lower our orbit. Instead, we’ll slow the ship by repeatedly crossing Venus’s upper atmosphere, as low as 130 km. Explains Thomas Fueren, EnVision’s Mission Director
Such maneuvers have been performed before, including during the Mars Reconnaissance Orbiter and ExoMars Trace Gas Orbiter missions. Unfortunately, the atmosphere of Venus is very different because it is much denser. Therefore, representatives of the European Space Agency are testing materials that will be suitable for building spacecraft that must withstand high temperatures and deadly friction.
As part of the EnVision mission, the spacecraft will perform an air brake maneuver
Undoubtedly, the experience can be gleaned from the Venus Express mission team that has been using aerodynamic braking for years. Initially, the mission was supposed to last 500 days, but in the end it turned out to be much longer and ended only after eight years, when the ship ran out of fuel. It was then that a controlled descent began, diving deeper and deeper into the atmosphere.
Gravity on Venus is about 10 times stronger than on Mars, making the entry velocity twice that of the Red Planet. This is also associated with much higher temperatures, so engineers must prepare their ship for really harsh conditions.
A separate problem arises from the presence of the so-called atomic oxygen, which is especially common in the upper atmosphere of the second planet from the Sun. Atomic oxygen is formed when oxygen is exposed to ultraviolet radiation emitted by our star. This type of oxygen is more reactive and can contribute to the deterioration of the vessel’s crust. However, the game is well worth it, as scientists intend to better understand the conditions in which Venus arose and evolved as part of the EnVision mission.
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