Esa satellite pair to show precise formation flight
Published: Sunday, Dec 1st 2024, 04:40
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Two European satellites are to demonstrate a precise formation flight in space for the first time. The mission is intended to provide insights into the solar corona, which is difficult to see.
The European Space Agency Esa plans to send its mission, called "Proba-3", into space from the Satish Dhawan Space Center in India on Wednesday. "Proba-3" is a demonstration mission. As the head of Esa, Josef Aschbacher, explained, Esa is using it to test a completely new way of operating in space. The two satellites, which together weigh 550 kilograms, will be sent on a large, elliptical orbit around the earth. It takes a good 19.5 hours for them to complete the orbit.
The two satellites spend around six hours of their flight in formation, in a fixed constellation 150 meters apart, when they are furthest away from the earth and therefore less affected by gravity. The shortest distance of the orbit to the earth is 600 kilometers, the furthest point is about 60,000 kilometers away.
Satellites to simulate solar eclipse
The mission is about more than just demonstrating precise formation flying: The satellites are to provide information about the solar corona, the atmosphere around the sun. Due to the bright and dazzling light of the sun, this only becomes visible during a total solar eclipse, i.e. when the moon blocks out the light of the sun for the part of the earth that is in its shadow.
This is exactly what the two satellites are supposed to simulate. One of them darkens and casts an eight-centimetre shadow on the second satellite, which is 150 meters away. Its telescope with a five-centimetre aperture should be exactly in the middle of the shadow. The sun is then hidden from the telescope and the corona becomes visible. For this to work well, the satellites, which control themselves via sensors, must work with millimeter precision.
Scientists could use this technology to obtain significantly more data about the corona. This is because a total solar eclipse is rare, whereas "Proba-3" can simulate one every few hours. And while researchers can only catch a glimpse of the corona for a few minutes during the solar eclipse, the new mission offers six hours of artificial solar eclipse.
First pictures possibly in March
So-called coronographers can already create such a simulation effect. However, they cannot see the inner part of the sun's corona well with just one satellite because diffracted light gets in the way. "Proba-3" can circumvent the disruptive effect of the dazzling light beams by the fact that the two satellites - and therefore the obscuration and telescope - are so far apart.
With the data on the sun's corona, researchers hope to learn more about space weather, ejections and solar storms, which can affect satellites and also have an impact on communication on Earth. They also want to understand why the corona is so much hotter than the sun itself.
Proba-3" could provide the first images of the sun's corona in March. A total of 14 Esa countries are involved in the two-year mission, including Austria and Switzerland.
©Keystone/SDA
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