On Wednesday, NASA announced that it had fundamentally changed its plan for returning samples from the Martian surface in the early 2030s. The samples are currently being collected by the Perseverance rover and are scheduled to be transported to Earth by a relay of rovers and rockets. Now, inspired by the success of the Ingenuity helicopter, NASA says it can lose one of the rovers and replace it with a pair of helicopters instead.
The return plan for the Martian samples involves a large set of challenges, but a key one is that the samples are currently in Perseverance, but will eventually need to land in a rocket that lifts off the Martian surface. That means Perseverance needs to get close enough to the rocket’s landing site – which we can’t choose exactly – to swap out the probes and possibly distract them from scientific targets. It also must not be too close when the rocket lands, as landing the rocket and associated hardware could pose a risk to the rover and its samples.
The original plan involved an emergency. Perseverance would approach the missile after landing and transmit the samples directly. If for some reason that didn’t work, a second rover sent to Mars by ESA would act as an intermediary, visiting a location where the samples were cached, recovering them, and then taking them to the rocket.
In the new plan, this second rover was eliminated. At his place? Two helicopters. These will be delivered as part of the same payload as the rocket carrying the samples into orbit. As a result, the new plan involves only a single lander (alongside the one that Perseverance supplied) that will carry both the missile and helicopters, significantly reducing the risk of the overall plan.
These helicopters will, of course, be based on the design of Ingenuity, which was sent to Mars as a test vehicle and far exceeded expectations, completing 29 flights in one year. Given this experience, NASA is confident that helicopters can be designed to carry small payloads and potentially complete multiple flights between the return rocket and where the samples are located — either on Perseverance or at a cache site.
After that, the plan remains the same. The samples are loaded into a container that will be placed on the NASA-designed Mars Ascent Vehicle, which will launch them into orbit. There, the containers will be transferred to the ESA-built Earth Return Orbiter, which will return them to Earth in 2033, where they will then fall through the atmosphere for recovery and study.
The next step will be approval by ESA, after which both agencies will start the preliminary design phase, covering all the details of the different vehicles needed. Meanwhile, Perseverance has already collected a dozen samples from the Red Planet’s surface.