SpaceX sending missions to the ISS might be cheaper than other launches, but it is still costly and a resource-intensive endeavor, with bigger and heavier rockets forced to use most of their space to store fuel.
To avoid that bulk, a team of researchers looking for alternative forms of propulsion has come with an interesting idea – powering rockets by blasting them with microwave beams from the ground. The team features engineers from Japan’s University of Tsukuba Nagoya University. They have managed to power a small quadrotor drone while it was airborne with a powerful microwave, as per the study published in the journal Spacecraft and Rockets.
Can it work for spacecraft?
The team explains that they weren’t sure if the idea would work prior to the experiment, according to a press release. But after several tests, they believe that microwave beams could not only lift an aircraft but could also be used for space rockets someday.
The researchers weren’t the first to experiment with powering a spacecraft with a microwave beam. But it was done after decades, which means they had more powerful beams, advanced technology, and better tracking systems, enabling them to accomplish what others couldn’t
“We used a sophisticated beam-tracking system to ensure that the drone received as much of the microwave power as possible,” said Kohei Shimamura, lead author, and Tsukuba engineer. “Moreover, to further increase the transmission efficiency, we carefully tuned the phase of the microwaves using an analog phase shifter that was synchronized with GPS units.”
More experiments required
As of now, the unique propulsion technique is at a nascent stage, but the team did manage to provide enough energy to the aircraft to keep it in the air. Still, it will take some time before a microwave beam can keep heavy rockets aloft because the efficiency of the experiment was just 0.43 percent, as per the study.
If we look at the bigger picture, that’s not enough. But it is still better than the 0.1 percent energy efficiency measured in the previous experiment. “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,” Shimamura added.
