Scientists want to send tiny, solar-powered spacecraft to Mars

Levitating devices could help scientists study hard-to-reach part of our planet – and others too

(Schafer et al. Nature)

Scientists want to send tiny, solar-powered spacecraft to examine difficult-to-reach parts of Earth’s atmosphere – and eventually other planets too.

The small devices are able to float in the air and could carry sensing instruments to monitor our climate as well as explore Mars, the researchers behind them suggest.

Unlike conventional spacecraft, they do not need fuel to stay floating in the atmosphere. Instead, they use energy from light, through a process known as photophoresis that has been used to make objects levitate for 150 years.

Despite that long history, the practical use of photophoresis has been limited to truly tiny objects or very powerful artificial light, and practical devices have not worked out. Now, however, researchers believe that they have made a centimetre-long flying device out of perforated sheets that can use natural sunlight to stay afloat.

The flying structure is made from two thin, perforated membranes that are attached together by tiny supports. They can be used to create a tiny disc that is then able to leveitate.

They could be sent up to the upper layers of the Earth’s atmosphere. If they can be scaled up slightly, they would be able to carry antennae and circuits that would allow them to be used to monitor the atmosphere and for other science work.

Eventually, the same design could be taken to other planets, they suggest. It is currently almost prohibitively expensive to send satellites to Mars, for instance – but doing so with the tiny spacecraft could allow researchers to monitor conditions on that planet, they say.

“If the full potential of this technology can be realized, swarms or arrays of such photophoretic flyers could be collecting high-resolution data on the temperature, pressure, chemical composition and wind dynamics of the mesosphere within the next decade,” Igor Bargatin from Penn University wrote in an article accompanying the new research.

The work is described in a paper, ‘Photophoretic flight of perforated structures in near-space conditions’, published in the journal Nature.