Enlarge (credit: NASAJPL-Caltech )

On Wednesday, NASA announced that it had made major changes to its plan for returning samples from the surface of Mars in the early 2030s. Currently being collected by the Perseverance rover, the samples are set to be moved to Earth by a relay of rovers and rockets. Now, inspired by the success of the Ingenuity helicopter, NASA is saying it can lose one of the rovers, replacing it with a pair of helicopters instead.

The Mars sample return plan involves a large collection of challenges, but a central one is that the samples are currently in Perseverance, but eventually have to end up in a rocket that takes off from the surface of Mars. That means that Perseverance will have to get close enough to the rocket's landing site—which we can't choose precisely—to exchange the samples, possibly diverting it from scientific objectives. It also can't be too close when the rocket lands since the rocket's landing and its associated hardware could pose a risk to the rover and its samples.

The original plan included a contingency. Perseverance would approach after the rocket had landed, and the samples would be transferred directly. If that didn't work out for whatever reason, a second rover sent to Mars by the ESA would act as an intermediary, visiting a site where the samples had been cached, retrieving them, and then delivering them to the rocket.