Scheduled for February 6, then for 8, the takeoff of the Solar Orbiter probe must finally take place in the night of Sunday, February 9 to Monday, February 10, from Cape Canaveral (Florida). The result of a collaboration between Europe and the United States – which supplied one of the ten scientific instruments and the rocket Atlas-V-141 -, this mission led by the European Space Agency (ESA) is going on a long study trip to the Sun.
To reach the elliptical orbit which will at times make it approach 42 million kilometers from our star – almost four times less than the Earth-Sun distance -, Solar Orbiter must first honor two meetings with Venus and one with the Earth, in order to benefit from what space specialists call a “Gravitational assistance”, a boost given by the gravitational force of the planets.
In November 2021, the probe will have reached its position and its mission can really begin, even if its instruments will have already taken some measurements during the first part of the journey. Unlike the probe NASA Parker Solar Probe, left in August 2018 and which will “graze” the Sun by passing only 6.2 million kilometers from its surface, Solar Orbiter will remain at a reasonable distance. But it will be for the better ” look in the eyes “, summarizes Anne Pacros, mission and payload manager for ESA.
Unlike its American cousin, entirely devoted to taking data in situ using instruments protected from the solar furnace by its heat shield, the European probe carries several telescopes. “Forty-two million kilometers is the limit for the optics of these telescopes, specifies Anne Pacros. They will provide the closest images ever taken of the Sun. ”
To do this, the Solar Orbiter heat shield, designed to withstand a maximum temperature of 520 ° C, is equipped with several portholes. Each is covered with a pivoting cover, similar to that which closes the peephole of a door. When the telescopes have to spy on and photograph the Sun, these covers will slide to release the portholes and then come back in place.
Complementary to Parker Solar Probe
To complete this remote sensing of solar activity, the machine will carry out measurements in situ, mainly the magnetic field and electrically charged particles that our star is constantly blowing throughout the Solar System. There too, we had to solve a few puzzles to make the vessel “invisible” to its own instruments, explains Anne Pacros: to avoid disturbing the magnetometer, “We favored non-magnetic materials and we have as few magnets as possible on board. For the pointing of the satellite, which is carried out using wheels with magnetic moment, one encapsulated these in a material which prevents the magnetic field from leaving “. In the same way, the external surfaces have been treated so that static electricity is evacuated from it, so as not to disturb the analysis of the particles of the solar wind.
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