What the ‘nanocardboard’ may look like while flying on Mars. Image: Penn Engineering
A team of engineers has proposed a ‘nanocardboard’ aircraft powered by light, which could one day explore the surface of Mars.
Joining NASA’s Perseverance rover on its mission to Mars will be an experimental helicopter designed to fly in a Martian atmosphere. In 2021, it is expected take off on a series of test flights lasting up to 90 seconds each.
However, engineers from the University of Pennsylvania’s School of Engineering and Applied Science have proposed an altogether different, science-fiction-like alternative for a flying device on Mars. In a blog post, they described a fleet of ‘nanocardboard’ aircraft that weigh as much as a fly and have no moving parts.
These strange craft levitate from a surface when bright light is shone on them. As one side heats up, the temperature differential causes air to circulate through the craft’s hollow structure. The air shooting out of corrugated channels in its sides thrusts it off the ground.
A study revealing the nanocardboard design has been published to Advanced Materials. The nanocardboard design has been in the works since 2017 and while inspired by the common packing material, the engineers also looked to the sandwich-structured composites used in architecture and aviation.
‘An entirely different approach’
The nanocardboard walls are made from hollow plates of aluminium oxide just a few nanometres thick. Latest testing of the concept showed the flyer’s ability to lift small payloads such as sensors and anything weighing no more than a few milligrams.
“In addition to carrying sensors, our flyers could simply land and have grains of dust or sand passively stick to them, then transport them back to the rover so it doesn’t need to travel as far,” said Igor Bargatin, who led the research.
To give a sense of scale, the engineers estimate that it would take more than 1m of the tiny craft to equal the mass of the Mars helicopter.
“The Mars helicopter is very exciting, but it’s still a single, complicated machine,” Bargatin added. “If anything goes wrong, your experiment is over, since there’s no way of fixing it. We’re proposing an entirely different approach that doesn’t put all of your eggs in one basket.”
The concept may also have terrestrial uses. Bargatin said that the craft could be placed in Earth’s mesosphere as a means of creating more accurate climate models.
