On June 15th, ESA reached a milestone as Solar Orbiter approaches the Sun. It managed to get 77 million kilometres away from it! That might sound like a lot, but in reality it is about half the distance from the Earth to the Sun. It’s very difficult to get spacecraft close to the Sun, because as you get closer, it gets hotter and harder to shield from the intense heat. Next month, the scientists will release the closest pictures of the Sun ever taken!
The Solar Orbiter Mission
Solar Orbiter was launched in February of this year from Cape Canaveral in Florida. Whilst an ESA mission, it also operates with participation from NASA. Its directive is to use both in situ and remote observations to help understand how our Sun influences the rest of the solar system.
Although this isn’t the closest to the Sun a spacecraft has been, there has never been one this close with telescopes able to look directly at it. On Earth, our atmosphere protects us from a lot of the solar spectrum. This is a good thing for our survival, but it means that even high quality observations from the ground don’t get the whole picture. With telescopes in space, like the Hubble Space Telescope, there is nothing in the way. Solar Orbiter can take pictures using different wavelengths, like ultraviolet, that can’t reach the ground.
The first close approach marks the end of the commission phase for Solar Orbiter, and starts the cruise phase. This will last until November 2021; then the exciting part can begin with the main science phase! During this phase, the spacecraft will reach its closest point to the Sun: 42 million kilometres.
What will it find?
Solar Orbiter will be gradually shifted out of the Sun’s ecliptic plane, using the gravitational pull of Venus. This will allow it to obtain the first proper view of the star’s poles. The activity here could provide new insight into the Sun’s magnetic field, which causes the solar wind. The solar wind is something that affects the whole solar system, so understanding it is hugely important.
There are 10 science instruments aboard Solar Orbiter, including 6 different telescopes. They will be tested over the next week, to make sure they’re ready for future observations. The very first images are due to be released mid-July. As well as this, new results are expected from the in situ instruments, which have never been this close to the Sun. Who knows what will be discovered?