ESA
Two European Space Agency (ESA) orbiters have staged an artificial solar eclipse in space for the first time to show with incredible clarity solar corona.
ESA’s Proba-3 mission has released the first set of images of the solar corona, which has long remained a mysterious area for astronomers. This upper and most rarefied layer of our star’s atmosphere has a key impact on space weather and the occurrence of solar storms, which is of interest to scientists.
As part of the mission, two ESA satellites equipped with a coronagraph and an oculus were brought to a clear distance of — 150 meters from each other, maintaining this position for several hours without manual control from the Earth. The instruments were aligned with the Sun so that the 1.4-meter disk of the oculator created an 8-cm diameter shadow on the ASPIICS optical coronagraph to provide clear images of the faint solar corona.
«Each complete image, covering the area from the closed Sun to the edge of the field of view, consists of three images. The only difference between them is the exposure time, which determines how long the aperture of the coronagraph is exposed to light. The combination of the three images gives us a complete picture of the corona», — explains Andrey Zhukov, principal investigator of the ASPIICS coronagraph from the Royal Observatory in Belgium.
Such an artificial eclipse can be created every 19.6 hours and sustained for up to 6 hours, compared to a few minutes of the much rarer natural solar eclipses that occur only once or twice a year.
The success of the Proba-3 mission was determined by the incredibly precise spacecraft positioning system developed as part of the ESA general technology support programs. For the first time, the satellites performed precise alignment in autonomous mode.
«The use of two spacecraft to form one giant coronagraph in space allowed us to image the inner corona with very low levels of scattered light in our observations, as we expected. Although we are still in the commissioning phase, we have already achieved flight in formation with unprecedented accuracy», — emphasized the mission leader Damien Galano.
The spacecraft also carry a Digital Absolute Radiometer (DARA), which measures the total energy of the Sun, and a Three-Dimensional Energy Electron Spectrometer (3DEES), which measures electronic activity in the Earth’s radiation belts. Currently, scientists are working on expanding the opportunities for observation for eclipses and the use of the data in models that could more accurately predict solar activity.
Source: Interesting Engineering