A mission dedicated to the study of solar physics, combining detailed in situ and remote measurements to improve our understanding of the heliosphere, solar wind and Sun’s magnetic field. A RHEA test engineer is currently working in the Solar Orbiter Science Operations Centre.

Solar Orbiter mission timescale

Mission launch: 10 February 2020
Planned mission duration: 7 years (nominal mission), plus 3 years (mission extension)

About the Solar Orbiter mission

The joint European Space Agency (ESA)/NASA Solar Orbiter mission is designed to study the Sun from close up, taking high resolution images of the Sun’s poles for the first time and helping us to understand the Sun-Earth connection.

It has a payload of 10 instruments. Four of them perform in situ measurements (in the immediate vicinity of the satellite). The remaining six carry out remote measurements of what is happening in the Sun.

Among the varied suite of instruments, there are magnetometers and plasma analysers, both performing in situ measurements. There are also extreme ultraviolet (EUV) and X-ray telescopes that perform remote measurements. The scientific payload was developed and will be operated by a consortium of nine European institutions and NASA.

About the Solar Orbiter’s orbit

Solar Orbiter Venus flyby. Image copyright: ESA/ATG medialab
Solar Orbiter Venus flyby. © ESA/ATG medialab

Solar Orbiter has already started capturing images of the Sun, but will reach its final orbit in November 2021, with the help of gravity assist manoeuvres at Earth and Venus. This will place it in a highly elliptical orbit where its distance from the Sun will vary between 1.2AU and 0.28AU. (An astronomical unit (AU) is a unit used for distances within our solar system and corresponds to the average distance between the Earth and Sun, which is around 150 million kilometres.)

Although the orbit will initially be confined to the same plane as the Earth and other planets in our solar system, there are plans to raise the inclination of the orbit to 33 degrees. This will provide a good vantage point to observe the Sun’s poles, which is impossible to do from the Earth. Close observation of the poles will help us understand how dynamo processes contribute to the generation of the solar magnetic field.

View Solar Orbiter’s trajectory around the Sun.

Solar Orbiter’s main technical challenges

Solar Orbiter will travel closer to the Sun than Mercury, the planet closest to the Sun in our solar system. As a result, the satellite and payload will be subjected to incredibly high temperatures that could reach over 500°C, as well as extreme cold when further away.

ESA and Airbus Defence and Space, the prime contractor, together with industrial partners, developed unique heat shield technology to prevent the high temperatures from damaging Solar Orbiter and its payload, while at the same time allowing the instruments an unrestricted view of the Sun.

Solar Orbiter’s initial scientific achievements

The images taken by Solar Orbiter on its first approach to the Sun are the closest images ever taken of our star. These images are already revealing some interesting details that could not be studied in detail before. An example of this are the so-called ‘campfires’, mini solar flares that seem to be a common feature of the surface of the Sun.

See Solar Orbiter’s first close-up views of the Sun.

Strange but true

Solar Orbiter relies on solar power to generate the electricity needed by the instruments. However, in order to prevent the solar panels from being damaged by overheating, during the craft’s closest approach to the Sun, the solar panels will have to be turned away from the Sun.

How RHEA is contributing to the Solar Orbiter mission

One of our test engineers is working in the Solar Orbiter Science Operations Centre (SOC) at the European Space Astronomy Centre (ESAC), building tests to verify and validate procedures and software tools at the SOC at system and subsystem levels. Given the complexity involved in preparing a SOC, a large fraction of the tests have to be automated in order to cope with what is normally a very tight release schedule.

Test engineers at ESAC interact with software and system engineers, and also with scientists. For that reason, they usually have a degree in Aerospace or Software Engineering. To work in science missions, familiarity with astronomy and astrophysics, at least at a basic level, is normally an advantage, although not required.

In addition:

  • A RHEA assembly, integration, test and verification (AIT/AIV) engineer based in ESTEC supported the functional test campaign.
  • A RHEA project controller supported the schedule and the financial management of the mission in the different phases and participated in the launch campaign.
  • RHEA operations engineers based in Airbus Defence and Space in Stevenage, UK, supported the operations team and the preparation of Solar Orbiter procedures.
  • MOIS toolsuite used for operations preparations and by Airbus.
Solar Orbiter liftoff. Image copyright: ESA - S. Corvaja
Solar Orbiter launched atop the US Atlas V 411 rocket from NASA’s Kennedy Space Center in Cape Canaveral, Florida, on 10 February 2020. © ESA – S. Corvaja

Main image: ESA’s Sun-explorer Solar Orbiter reached its first perihelion, the point in its orbit closest to the star, on 15 June 2020, getting as close as 77 million kilometres to the star’s surface. © ESA/Medialab

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