One challenge drone makers come across, whether they’re creating flying devices for commercial use or personal use, is how to keep them running for a prolonged period of time.

We’ve previously mentioned Stanford University’s drone that uses microspines to stick to vertical or horizontal surfaces to take a break from bad weather conditions or save battery life, but now Harvard University has announced its own research project that uses static energy to attach to walls and ceiling for exactly the same reasons.

Names RoboBees, these tiny drones weigh the same as a honeybee and are only slightly larger than the flying insect. They, like Stanford’s drones, can attach to surfaces in order to save energy.

“Many applications for small drones require them to stay in the air for extended periods,” said Moritz Graule, the first author of the paper. “Unfortunately, smaller drones run out of energy quickly. We want to keep them aloft longer without requiring too much additional energy.”

“A lot of different animals use perching to conserve energy,” added Kevin Ma, a co-author. “But the methods they use to perch, like sticky adhesives or latching with talons, are inappropriate for a paperclip-size microrobot, as they either require intricate systems with moving parts or high forces for detachment.”

The team instead opted to experiment with electrostatic adhesion to stick to the surface, which is the same energy that causes statically-charged objects such as balloons to stick. But where balloons will lose their stickiness, the researchers integrated an electrode patch that maintains electrostatic adhesion, meaning once the RoboBee has attached, it can continue to cling on for as long as required.

However, these little creatures won’t be able to carry heavy equipment such as high-performance cameras, but they can still be used for surveillance missions. RoboBees have, in fact been designed for search and rescue missions, possibly navigating their way through tiny cracks and sending back a signal to alert human teams to life.