First space-like testing of exoplanet hunter Plato

Inspection of the space simulator. One of the goals is to verify to within one millionth part of a circle where the camera is looking at. Here the mechanism–or gimbal–that moves the camera is being inspected using a theodolite, an optical instrument that measures rotation angles. Because even the smallest dust particle can cause deviations, this is performed in a cleanroom. A video connection provides the link with the control room and an instrument specialist outside. Credit: SRON

The European Space Agency (ESA) is working on a new exoplanet-hunting mission called Plato that will be launched in 2026. Astronomers think that Plato’s ability to see smaller planets in larger orbits than current telescopes will help them find planets the size of Earth that are in the habitable zone. The SRON Netherlands Institute of Space Research is helping with the project by putting Plato’s cameras through their paces in a simulator of space that they built themselves. Researchers at SRON have finished testing the prototype, and everything works as it should. At ESA, the frame for the cameras is being tested for a month in a vacuum to see how well it will hold up in space.

Scientists at the SRON Netherlands Institute for Space Research made a space simulator so they could test Plato in conditions that were like those in space. It makes space-like conditions by having very low temperatures and pressure, and it also makes artificial starlight. A system that still works in these harsh conditions moves the camera so that the whole field of view can be tested. The researchers can tell to within a millionth of a circle where the camera is pointing.

Plato’s prototype camera, called the Engineering Model, went through a long series of tests over a six-week period to show that it could do what was needed and to make sure that its performance wouldn’t change if it was cycled through all the temperatures that could be expected. “It turns out that the Engineering Model works as expected in every way,” says Lorenza Ferrari, who is in charge of the project. “This is great news for Plato as a whole, and it also shows how well our space simulator works.”

During the spring and summer, additional simulators in Paris and Madrid will use the same camera to replicate the test results from SRON. This will allow the three setups to be properly calibrated. The final version of the Plato satellite will have 26 cameras, and it will be called the Flight Model. All of them will be tested in Groningen (SRON), Paris (IAS), and Madrid so that the launch can happen on time in 2026. (INTA). In the fall of this year, SRON will get the first of eight Flight cameras. It will take until the end of 2023 to test all of them.

ESA is putting the optical bench that will hold the 26 cameras in place in Europe’s largest thermal vacuum chamber for a month to see how well it will hold up in space. “Thermal cycling” is used to see how the optic bench reacts when the temperature changes between light and dark, and “thermal balance” is used to measure the temperature at which it works in these conditions.

Source: SRON Netherlands Institute for Space Research