On March 6, 2014, the U.S. Department of Energy (DEO) announced:
“Solar power directly from space may arrive sooner than you think.”
Not everyone knows that renowned sci-fi author Isaac Asimov first envisioned collecting solar power in space and transmitting it wirelessly to the ground – in his 1941 short story Reason.
More than two decades later, in 1968, aerospace engineer Peter Glaser published the first technical article on space-based solar power (SBSP), Power From The Sun: Its Future. He described a platform in geostationary orbit that generated solar power maintained its relative position over the same place on earth.
International interest in going solar in space persisted through the 1970s but fizzled 20 years later before the New Millennium. Industry experts said that while the technology was feasible, it was economically unrealistic.
In its March 2014 publication Space-Based Solar Power, the DOE shared a couple of interesting facts:
- Every hour, more solar energy reaches the Earth than humans could use in a year
- About 30% of this energy is reflected back into space by the atmosphere
There are no clouds in space – or atmosphere or seasons or nighttime. Solar panels mounted on orbital satellites would capture and transmit significantly more energy than solar panels on the planet’s surface.
Solar panel equipped energy transmitting satellites collect high intensity uninterrupted solar radiation by using giant mirrors to reflect huge amounts of solar rays onto smaller solar collectors.
The captured radiation is then sent over a wireless connection to Earth in a safe and controlled way, either as a microwave or laser beam.
Energy researchers have long been interested in the possibility of SBSP as a solution to many of today’s planetary challenges:
- In space, the sun is always shining with zero energy generation downtime
- The tilt of the Earth has no negative impact on the collection of power
- There is no diffusing atmosphere to reduce the intensity of the sunlight so it is transmitted at full force with maximum efficiency
- People in remote communities around the globe could access reliable and clean energy without relying on the traditional grid to a large local power plant
With all these advantages, coupled with rising concern over carbon pollution, this new energy technology moving away from the realm of pure science fiction. Serious action is underway to install solar panels in space.
In 2014, here is how the space based solar powered DOE envisioned orbital solar power collectors:
“Self-assembling satellites are launched into space, along with reflectors and a microwave or laser power transmitter. Reflectors or inflatable mirrors spread over a vast swath of space, directing solar radiation onto solar panels. These panels convert solar power into either a microwave or a laser and beam uninterrupted power down to Earth. On Earth, power-receiving stations collect the beam and add it to the electric grid.”
Five years later, in March 2019, China announced its plans to build the world’s first solar power station in space to provide “inexhaustible clean energy.”
According to Pang Zhihao at the China Academy of Space Technology, a space solar power system orbiting the Earth at an altitude of 36,000 km (22,370 mi) could collect 100% of the energy of the sun’s rays with no interruptions from atmospheric conditions or sunlight loss at night. The Chinese claimed they were testing the unconventional technology and target the station’s completion by 2050.
The Japanese are developing an orbital array of photovoltaic dishes.
Because a single-unit orbital solar collector would have to be about as big as a city skyscraper, engineers shifted to modular designs that can be assembled in space.
In May 2020, the U.S. Navy gave its new solar power satellite hardware an orbital test. A U.S. Naval Research Laboratory experiment to capture solar power in space for use on Earth flew to orbit on May 17 aboard the U.S. Air Force X-37B spaceplane. The photovoltaic radio-frequency antenna module to be tested is part of a comprehensive investigation into terrestrial use of solar energy collected in space.
The Navy module converts sunlight for microwave power transmission rather than optical power transmission to avoid energy loss passing through clouds and the planet’s atmosphere.
The Pentagon says it is evaluating the naval technology as a viable way to provide energy to remote installations such as forward operating bases and disaster response areas.
SBSP is being actively pursued by Japan, China, Russia, and the U.S.
Solar farms in space may soon fly above us, pitched as an eco-friendly solution to mitigate the global energy crisis. This sounds too good to be true. Is there a downside? Only time will tell.