GN WASHINGTON - Engineers preparing the next American Mars rover have installed one of its most exciting experiments - a chopper.

The mini-helicopter is regarded as a bonus on the 2020 mission. It will be the first aircraft deployed on another world. If it works, it will be fantastic, but if it doesn’t it won’t detract from the overall goals.

The US space agency’s (Nasa) next Mars rover is a near-copy of the one-tonne Curiosity vehicle that has operated successfully in Gale Crater since 2012. The new mission will be aimed at a different target - a 50km-wide depression called Jezero Crater.

Engineers are nearing the end of the rover’s assembly at Nasa’s Jet Propulsion Laboratory in California. They’ve positioned the 1.8kg “Scout” chopper under the big robot. The idea is that the rover will find a safe place to put the aircraft on the ground shortly after landing.

That does mean, however, that the twin-rotor device must travel with some protection.

The rover’s touchdown mechanism uses rockets and these will kick up stones and dust. As a consequence, a shield is being fitted around the helicopter to deflect any debris. There are no scientific instruments on the solar-powered Scout. Its job is merely to demonstrate the practicality of flight on another planet.

It will, though, carry a camera and researchers will certainly be interested in the pictures it takes to give context to the rover’s exploration.

Ultimately, however, small helicopters could become a regular feature of future missions, not just to do reconnaissance but to study the more hard-to-reach places such as cliffs, caves and deep ravines.

Nasa recently approved a mission to put a helicopter on Titan, a moon of Saturn. Like the Earth and Mars, Titan has an atmosphere - a thick one - and can support aero-vehicles.