The Solar Orbiter mission will perform closeup observations of the Sun and its effects on the solar system. The spacecraft will carry a suite of complementary instruments that will measure the particles fields and waves of the plasma through which it travels, and at the same time make observations of the Sun’s surface and outer atmosphere, the photosphere and corona.
At its closest point Solar Orbiter will be closer to the Sun than the planet Mercury at a distance of 28 astronomical units (42 million kilometers) in an orbit that takes it out of the ecliptic plane. It will be one of the closest approaches of the Sun by any spacecraft. At its closest approach where sunlight is thirteen times more intense than it is for satellites orbiting the Earth, Solar Orbiter must survive intense thermal radiation. To achieve this, the design includes a heat shield and incorporates new high-temperature solar array technology.
To position itself in this challenging orbit Solar Orbiter will make a complex series of gravitational-assist flybys past both Earth and Venus. The completion of these manoeuvres will require a very advanced and highly autonomous AOCS and a chemical propulsion system. From this orbit it can perform long duration observations of the same region of the Sun’s surface and have visibility of the Sun’s polar regions.
The AOCS provides all the functionalities required to control the spacecraft attitude and rates and to perform orbit correction manoeuvres during all phases of the mission. The system consists of a dedicated set of sensors: star trackers, inertial measurement unit, fine sun sensors, and a dedicated set of actuators.
The Solar Orbiter chemical propulsion system will provide the required deltaV for the interplanetary transfer orbit and the attitude control required by AOCS. The design is that of a conventional bi-propellant chemical propulsion system.
The Sun is vital for life on earth but can also cause major problems for satellites and earth based systems. The Sun releases bursts of highenergy particles coronal mass ejections which can disrupt electrical power distribution systems, cause computers to crash, damage satellites and endanger astronauts. Solar Orbiter will provide scientific data to better understand the mechanisms on the Sun that cause these violent and disruptive outbursts.
OHB Sweden contributions
OHB Sweden has been selected by the European Space Agency (ESA) and Airbus DS (UK) as contractor for the Attitude and Orbit Control System (AOCS) and the Chemical Propulsion System (CPS).
Solar Orbiter is the first medium-class mission in ESA s Cosmic Vision programme.
Solar Orbiter is also a collaboration between ESA and NASA where a launcher will be provided by NASA, and one instrument and one sensor will be contributed from the United States.
Solar Orbiter is scheduled for launch in 2018. The mission lifetime will be 7 years.