On February 18, the European Solar Orbiter probe will perform a close flyby of Venus. This maneuver will allow it to see the poles of the Sun.
What are gravity maneuvers for?
Solar Orbiter was launched in 2020 to study the Sun, its activity and the interior of the heliosphere. To solve these problems, it needed to get closer to our star at a distance less than the distance between it and Mercury. For this purpose, Solar Orbiter performed a series of gravitational maneuvers near Venus that reduced the perihelion of its orbit to 42 million km.
Now Solar Orbiter begins the next phase of its mission. In its course, the spacecraft will study the polar regions of the Sun, which are not visible from Earth. And to do that, it needs to meet Venus again and take advantage of its gravity.
The fact is that the orbits of all the planets lie roughly in the same plane. To see the poles of the Sun, the Solar Orbiter orbit must be “tilted” relative to this plane. The problem is that this is a very energy-intensive maneuver, requiring more fuel than the spacecraft can take with it. That’s why the Solar Orbiter will need a new encounter with Venus. The planet’s gravity will allow its orbital inclination to be increased to 17° at virtually no fuel cost.
Precise calculation
During the upcoming approach, Solar Orbiter will pass just 379 kilometers from the surface of Venus. This is less than the ISS orbital altitude. The Solar Orbiter’s trajectory is designed to get the most out of it while avoiding exposure to Venus’ atmosphere.
One potential problem is heating. During the flyby, Solar Orbiter will be directed by a heat shield toward the Sun. However, the vehicle will still be “bathed” in the flow of heat coming from the hot atmosphere of Venus. Some parts of Solar Orbiter will experience a significant temperature increase, but according to engineers’ calculations, it should not exceed a safe limit.
Mission specialists will also take advantage of the upcoming flyby to collect scientific data. Unfortunately, due to the need to hold a certain orientation of the heat shield, the spacecraft will not be able to take pictures of Venus with its cameras. At the same time, it will make measurements of the plasma and magnetic environment in the planet’s neighborhood. These data will contribute to studies of how the solar wind affects the atmospheres of planets beyond Earth.
Earlier we covered how Solar Orbiter took the most detailed images from space.
According to ESA
