Harnessing the power of the sun is currently very much in vogue. In late 2022, US scientists announced a nuclear fusion breakthrough that could lead to a clean, renewable, and essentially unlimited source of energy powering the world within a few decades.
In reality, we have been using the power of the sun in a roundabout way for decades. Solar panels are able to convert the rays of the stars into energy here on earth without releasing harmful greenhouse gases into the air. The only downside is that these panels cannot provide continuous supply. Cloudy days prevent the sun’s rays from reaching the earth. And of course the sun doesn’t shine at night.
So why not take the solar panels into space? They would be tapping into the sun’s nearly unlimited energy supply 24 hours a day. Sci-fi legend Isaac Asimov wrote of an earth sustained by such power in Reason. The idea would be to collect electricity in a satellite and beam that energy home. Scientists have been trying to figure out how space solar energy could power our world since the Apollo program, but satellites have been too expensive to build and launch.
This month, thanks to a major philanthropic donation in 2013, Caltech scientists are taking the first tentative steps toward a solar-powered future in space. The Space Solar Power Demonstrator (SSPD), a 110-pound prototype designed to test key technologies in three experiments, was launched on a SpaceX Falcon 9 rocket Tuesday, January 3.
The ultimate goal is to deploy a constellation of space solar panels that could be over half a mile wide, forming a space power plant that then radiates solar energy back to Earth. This process involves wireless power transmission, converting radio waves into power at ground level, where receivers can convert the power for use on power grids. (Caltech has a great explanation of how to effectively funnel this energy to Earth.)
Hitchhiking into orbit attached to a Momentus Vigoride spacecraft, the SSPD will deploy a 6-foot-square structure to demonstrate the deployment mechanisms of space solar panels in what is known as DOLCE, the Deployable on-Orbit ultraLight Composite Experiment investigate. Another instrument, ALBA, will analyze 22 different types of photovoltaic cells to see how they cope with the extreme environmental conditions of space, and a third, MAPLE, will test energy transfer mechanisms using a range of microwave transmitters.
“We plan to order DOLCE deployment within a few days of gaining access to Momentus’ SSPD. We should know immediately if DOLCE works,” said Sergio Pellegrino, civil engineer at Caltech and co-director of the SSPD, in a press release.
Unfolding is, in a way, the easy part. The demonstrator has been tested on Earth, but how it fares in space remains to be seen. The ALBA and MAPLE experiments will take much longer as scientists want to see how they perform over time and in different environments.
“No matter what, this prototype is a huge step forward,” said Ali Hajimiri, a Caltech engineer and co-director, in a press release.
However, space solar is not a quick fix to the climate crisis. We already have solar energy technologies and ways to store energy when the sun isn’t shining here on earth. There are also potential issues with building power plants in an already crowded orbit and the overall cost of the project. However, space-based solar energy could bring power to regions of the world that currently lack access to reliable electricity, providing a clean source of energy – day and night – to power the planet.
Updated January 3: Added successful launch of SSPD on Falcon 9.