Breaking News
China's visa-free boom is rewriting inbound tourism
A New Kind Of Hybrid Is Coming. See The 9 Extended-Range EVs Hitting America Soon
America's Public Schools Have an Empty-Desk Problem
Saudi, Turkey, Pakistan agree to Riyadh secretariat under defence pact;
Top Tech News
Here's What to Expect as Air Taxis Actually Begin to Take Off
'Wood Foam' Startup Uses Logging Waste as Substitute for Plastic, Producing 400 Pounds Daily
How a Group of Young Men in 1933 Solved a Water Crisis in The Desert -- And Nobody Knows About It
This American Battery Could Break China's Grip On The EV Supply Chain
Tesla's Cybercab Launch Is Next Week. Here's What Tesla Still Needs To Prove
800-passenger commercial plane boldly reinvents how we will fly
Does Ultra-Fast Charging Ruin An EV Battery? BYD Did It 350 Times In 9 Days To Find Out
Singapore is experimenting with biological computing using living human neurons...
It's Happening - Europe is Building an Impossible Fusion Reactor
Portable 1MW Kaleidos Microreactor Secures Critical Nuclear Fuel Deal Through 2030s
Early Beamed Microwave-Powered Rocket Launches and Drone Power
This limitation could be overcome by wirelessly transmitting the needed power to the rocket through a beam of microwave radiation. A research team from Japan has investigated the viability of using such microwave-powered propulsion for real-world applications.
In a study published this month in the Journal of Spacecraft and Rockets, researchers led by the University of Tsukuba have demonstrated wireless power transmission via microwaves for a free-flying drone and determined the efficiency of this process.
Previous analyses of this kind were carried out decades ago and mostly considered microwaves of a low frequency (a few gigahertz; GHz). Given that the power transmission efficiency increases as the operating frequency is raised, the team behind this latest research used microwaves with a relatively high frequency (28 GHz). The team's drone weighed roughly 0.4 kilograms and hovered for 30 seconds at a height of 0.8 meters above the source of the microwave beam.
The researchers measured the efficiencies of the power transfer through the beam (4%), the capture of microwaves by the drone (30%), the conversion of microwaves to electricity for propulsion (40%), and other relevant processes. Based on this information and an analytical formula, they calculated the overall power transmission efficiency in their experiment to be 0.43%. For comparison, in a previous study, the team measured the total transmission efficiency for a fixed-position (rather than free-flying) drone to be 0.1%.
"These results show that more work is needed to improve the transmission efficiency and thoroughly evaluate the feasibility of this propulsion approach for aircraft, spacecraft, and rockets," explains Shimamura. "Future studies should also aim to refine the beam-tracking system and increase the transmission distance beyond that demonstrated in our experiment."
Although microwave-powered rocket propulsion is still in its early stages, it could someday become a superior way to launch rockets into orbit given the high onboard-fuel demands of conventional propulsion techniques.