Sitting near the back of the Science Museum is a full-size model of a spacecraft that’s currently on a journey to Mercury. BepiColombo is a collaboration between the European Space Agency and the Japan Aerospace Exploration Agency, and its mission is to head to Mercury to study the planet’s surface and magnetic fields to learn about what lies beneath the surface.
As the actual satellite is now on its way to Mercury, and could never go on display anyway due to the need to be protected from contamination, the Science Museum has the next best thing – the Structural Thermal Model (STM), which is a full sized mock-up used to test BepiColombo’s resilience during its 7-year journey to Mercury.
In the course of testing, the model was subjected to extremes of temperatures ranging from -190°C to 400°C, recreating the conditions the spacecraft will face when in shade and when in the illuminated face of Mercury.
So while it’s a model, it’s not just an airfix kit, but a full equivalent of the actual spacecraft and was used in actual testing for the spacecraft itself. That makes it a bit more special than you might otherwise expect.
The spacecraft model is on semi-permanent display near the IMAX cinema at the back of the ground floor of the Science Museum. What’s impressive is the size of the spacecraft – these are really huge machines and putting then on display is a good way of reminding us that not everything in science is the study of the very small these days. There’s still some big machine engineering available.
The BepiColombo spacecraft’s own 7-year journey to Mercury is designed to slow it down from the speeds originally needed to leave earth’s orbit, so it will use the gravity of three planets to slow it down. It will pass Venus twice, come back past Earth once — in April 2020 — and pass Mercury six times before it’s slow enough to be captured by Mercury’s weak gravity and go into orbit.
However, keep an eye out on 13th April 2020, as that’s the expected date of BepiColombo’s closest approach to Earth before it’s flung back towards the Sun again, never to return.