SPIE Astro 2024: integration of Plato’s cameras starts in Germany

18 Jun 2024

Exoplanet-seeking mission to use 24 “normal” and two “fast” cameras to inspect stars and planets.

Activities to integrate Plato’s cameras have commenced in OHB’s Space Center & Optics facility in Oberpfaffenhofen, Germany. The cameras are to be attached to Plato’s optical bench, the surface that will keep all cameras pointed in the right direction. The first of 26 cameras has now been successfully integrated, ESA announced last week.

Plato, which stands for PLAnetary Transits and Oscillations of stars, will use 24 “normal” and two “fast” cameras to look at more than 100,000 stars and search for Earth-like planets around them. The mission, set for launch in 2026, will use the transit method to characterize such planets; when planets in front of their host stars, they dim the measurable starlight output, revealing information about a planet’s size, mass and density.

During the four-year mission, the cameras will use a dedicated pointing technique to look at the same stars for a long period. Together, the 26 Plato cameras will be able to image about 5% of the sky at one time, states ESA.

Plato’s scientific payload, consisting of the cameras and electronic units, is provided through a collaboration between ESA and the Plato Mission Consortium, which comprises various European research centres, institutes and industries.

Plato mission

Scheduled for launch in 2026, Plato was selected as the third medium (‘M-class’) mission in ESA’s Cosmic Vision 2015–25 plan back in 2014. When Plato was adopted, it was decided to review of the mission in 2022, because of the challenges associated with development of the complex set of 26 cameras.

Plato successfully passed this review and the next major milestone is the ongoing spacecraft critical design review – to verify the design of the complete spacecraft before proceeding with the next stage: assembly.

One of Plato’s mission objectives is to discover whether a “second Earth” exists in the Universe. Plato, characterized as a “planet hunter”, will focus on the properties of rocky planets orbiting Sun-like stars. In particular, it will focus on planets in orbits up to the habitable zone – the so-called “Goldilocks” region around a star, where the temperature is optimal for liquid water to exist on a planet’s surface.

As well as looking at these planets, Plato will analyze their host stars. Using data from the mission, scientists hope to perform stellar seismology, gathering evidence of “starquakes” in the imaged stars. This will give insight into the characteristics and evolution of the stars, improving our understanding of entire planetary systems.

Multiple cameras

Plato will use 26 cameras at once to observe terrestrial planets in orbits up to the habitable zone of bright Sun-like stars, and to characterize these stars. Using such a large number of cameras will enable a combined higher signal-to-noise ratio and larger field of view than has been possible with previous missions.

Through the observations of bright stars, Plato will assemble the first catalog of confirmed and characterized planets with known densities, compositions, and ages, which will include planets in the habitable zone of Sun-like stars.

Plato will identify interesting targets for further investigation by the NASA/ESA/CSA James Webb Space Telescope and by ground-based observatories. Plato’s discoveries will be complemented by exoplanet findings by ESA’s Gaia mission and by NASA’s future Roman Space Telescope. Plato will be followed by ESA’s Ariel, scheduled for launch in 2029, which will observe a large and diverse sample of exoplanets to study their atmospheres in great detail.