ESA’s newly approved Lunar Meteoroid Impact Observer, Lumio, mission will orbit an Earth-Moon Lagrange point to detect meteoroid flashes on the night-time lunar farside. In addition Lumio will also perform an innovative autonomous navigation experiment – using its camera images to calculate the spacecraft’s current orbital position and distance from the Moon.

Shown here is the new variable magnification, hardware-in-the-loop testbed being used to develop and test the necessary vision-based navigation algorithms to accomplish this ambitious task. Known as ‘Retina’, or Realistic Experimental FaciliTy for vision-based Navigation, it is composed of several opto-mechanical parts installed along two parallel optical lines in an optical bench in a darkroom.

Both lines replicate the same setup. A high-resolution, high dynamic range microdisplay screen displaying synthetic scenes of the Moon is linked to a ‘collimator’ lens system that can project the observed scenes at infinity, a relay lens assembly to achieve variable magnification capabilities and a camera instrument mimicking the charactistics of real vision-based systems.

Retina has been developed by the Deep-space Astrodynamics Research and Technology, DART, group at Politecnico di Milano’s Department of Aerospace Science and Technology, overseeing the Lumio project for ESA.

Francesco Topputo, Professor of Space Science at Politecnico di Milano, explains: “If this experiment can indeed determine Lumio’s position without any ground station in the loop, it would pave the way for low-cost autonomous navigation in cislunar space.”

Lumio is a briefcase-sized 12-unit ‘CubeSat’ – a low-cost small spacecraft built up from standardised 10 cm boxes – which will be placed in orbit around the Earth-Moon Lagrange Point 2, a point of gravitational equilibrium between the two bodies.

The mission was one of two winning concepts from the ESA SysNova Lunar CubeSats for Exploration challenge which has now been given funding through the ‘Fly’ Element of ESA’s General Support Technology Programme, aimed at early demonstration of promising technology in space.

Lumio is being put together for ESA by a consortium including Politecnico di Milano, Argotec, Leonardo, IMT- Ingegneria Marketing Tecnologia, Nautilus, ECAPS, LMO and S&T Norway.