Solar flare, headed our way (Image: SOHO/ESA/NASA/SPL)

A SWARM of “smart dust” spacecraft, positioned at a sweet spot between the Earth and the sun, could alert us to the approach of dangerous space storms well before a conventional craft can. The first prototypes are due for launch into low-Earth orbit this year, perhaps as early as May.

Mason Peck, a mechanical engineer at Cornell University in Ithaca, New York, and his colleague Justin Atchison have designed a 1-centimetre-square spacecraft that is 25 micrometres thick and weighs under 7.5 milligrams. The craft is modelled on the dust particles that orbit …