ESA’s PLATO observatory: OHB System AG readies for integration of 26 cameras

Oberpfaffenhofen, 13 March 2024 – The European Space Agency’s (ESA) scientific mission PLATO (PLAnetary Transits and Oscillations of stars) is coming along in great strides: The integration of the first set of cameras on the so-called optical bench is currently being prepared at the Bavarian site of the industrial prime contractor OHB System AG. When finished, the satellite will have 26 cameras, which will search for Earth-like planets orbiting distant stars. In order to be able to carry out observations undisturbed, PLATO will be placed behind the Earth as seen from the sun at the Lagrange point L2^*). Representatives of the project partners who conceived and developed the scientific instrument attended a conference in Oberpfaffenhofen to mark the begin of the integration activities in OHB's newest ISO 5 cleanroom.

Thomas Walloschek, PLATO Project Manager at ESA: “It is really great to see how things are coming together when the industrial team led by OHB as prime contractor, the PLATO mission consortium responsible for the payload development and the ESA team in charge of the mission all put their efforts together. This can only happen if everyone works together in a cooperative and supportive spirit and pursues the same goal: a successful scientific mission. The next big step for the payload module begins now with the finalisation of this remarkable ISO 5 facility and the start of the integration of the cameras and payload data processing systems.”

Prof Dr Heike Rauer, DLR (German Aerospace Center) coordinator of the international PLATO mission consortium, which includes members from 15 countries: “It is amazing to see how our dream of a telescope able to detect and characterise Earth-like planets around stars like our own is becoming a reality step by step. With the finalisation of the first set of flight cameras, the project is moving ahead towards the mission launch in the not-too-distant future. I really enjoy working in this team which brings together scientists and engineers from industry under the leadership of OHB, ESA and scientific institutions all over Europe, all working towards a common goal.”

Chiara Pedersoli, CEO of OHB System AG: “I really enjoyed the exchange with the scientists involved in the PLATO project, it was truly inspiring. Our new cleanroom is ideally equipped for the requirements of the instrument and subsequent satellite integration. It has an ISO 8 and an ISO 5 area which can be configured with maximum flexibility, according to the specific project needs. With a thermal vacuum chamber designed according to our requirements, we now also have the opportunity to carry out some environmental tests ourselves here at the OHB Space Centre for Optics and Science. Our new facilities are a testimony to our commitment to science missions with their great need for flexibility, and to Bavaria as a space technology location."

In addition to the representatives from ESA and the DLR, delegates of the Italian National Institute for Astrophysics (INAF – Istituto Nazionale di AstroFisica), coordinator of the design and production of the PLATO cameras, came to Oberpfaffenhofen together with scientists and engineers from various other European research institutes to visit the cleanroom and take a look at the flight hardware integration.

The mission: exoplanets and their stars

At a distance of 1.5 million kilometres from Earth, PLATO will be on the lookout for “new worlds”. This requires the optical payload to be perfectly aligned and stabilised, as it involves the precise, long-term, and uninterrupted photometric observation of bright stars in the visible range. In this way, the cameras can detect very small and regular losses of light that occur when planets transit their stars, temporarily blocking out part of the starlight.

The observatory will provide scientists with new insights into both exoplanets^**) and their stars. On the one hand, the objective is to understand the formation of planets and how they evolve over time. Scientists also expect answers to the question of whether our solar system is unique or what properties Earth-like planets in the habitable zone of other stars have. On the other hand, measurement of the seismic activities of stars is an objective of research work. The observations enable a more precise characterisation of stars outside our solar system, including their age. The knowledge of the physical structure of stars is fundamental to assess the possibility to find exoplanets with characteristics similar to our Earth, where life is possible.

The project partners: European academia and industry

OHB System AG has been selected by ESA as the prime contractor for the development of PLATO, the third medium-class mission in the Cosmic Vision programme. In addition to supplying the two and half-ton satellite, the contract also includes support for the launch campaign and the in-orbit commissioning phase. OHB's involvement will only end with the in-orbit verification, which will prove the satellite's full functionality in orbit.

For the development and production of the PLATO satellite, OHB is relying on its core partners Thales Alenia Space in France (avionics, i.e., the on-board handling of data as well as the satellite's attitude and orbit control) and the UK (integration and testing of the satellite platform) and Beyond Gravity Switzerland (optical bench for the cameras). Other European companies, including sister companies OHB Sweden, OHB Hellas and OHB Czechspace, are also involved as subcontractors. The 26 approximately knee-high cameras and the on-board instrument data processing system were developed and manufactured by a consortium of European research institutes under the overall coordination of ESA. The first set of ten cameras have recently been delivered to OHB System AG in Oberpfaffenhofen, Bavaria, and will now gradually be integrated into the optical bench.
 

<sup>*) In this orbit, a satellite keeps its orientation in relation to the sun and the Earth. Its solar panels facing the sun generate the required energy. The observation period, which usually lasts three months, is followed by a swing manoeuvre in order to protect the payload from the direct sunlight.

**) While planets are objects that are under the gravitational influence of the sun, i.e. orbiting it, exoplanets (or extrasolar planets) are found outside our solar system, i.e. in the gravitational field of other stars.</sup>