To stay within budget, opportunities could be provided to use established resources, such as the new Ariane 6 launcher for a 'piggyback' ride on the launch of the main payload or the Moonlight programme for lunar communications and navigation services.

Xavier highlights: "Ideally, candidates should be able to develop their idea from start to finish. That means that the company or consortia not only proposes the mission, but also has the ability to see it through the implementation phase."