Caltech’s space solar power project completes inaugural space mission

“Solar power beamed from space at commercial rates, lighting the globe, is still a future prospect. But this critical mission demonstrated that it should be an achievable future,” said Thomas F. Rosenbaum, Caltech President.

What does it mean for the future of solar power?

Now that SSPD-1 has finished its space mission, the engineers on Earth have learned valuable lessons from these tests, which will guide the development of future space solar power projects.

The aim of the project is obvious. Unlike Earth-based solar plants that are affected by weather conditions and nighttime, space-based solar power plants can collect energy from the sun continuously. 

This ensures a consistent and uninterrupted power supply, overcoming the limitations of daylight and weather fluctuations on Earth.

Space-based solar power can also contribute significantly to reducing reliance on fossil fuels, helping to mitigate climate change and decrease pollution. It provides a clean and sustainable alternative energy source.

But not everything went according to the plan

While all experiments on SSPD-1 were successful, there were unforeseen challenges, providing valuable insights for future space solar power array designs. 

During the DOLCE deployment, which demonstrated the structure of scalable modular spacecraft, a wire snagged, causing a delay and structural damage. 

The team, under time pressure, used cameras and a lab model to identify solutions, discovering that warming the damaged system with sunlight and reflected solar energy improved deployment. 

Further issues arose as part of the structure jammed under the deployment mechanism, a problem not encountered in lab tests. 

We already have solar panels in space

For over a decade, the dedicated research team at the California Institute of Technology (Caltech) has been diligently advancing its Space Solar Power Project (SSPP). 

Led by professors Harry Atwater, Ali Hajimiri, and Sergio Pellegrino, the project gained international attention for its advancements. 

“It’s not that we don’t have solar panels in space already. Solar panels are used to power the International Space Station, for example,” said the leaders of the mission. 

“But to launch and deploy large enough arrays to provide meaningful power to Earth, SSPP has to design and create solar power energy transfer systems that are ultra-lightweight, cheap, flexible, and deployable,” they continued in the press release.

Currently, commercially available space solar cells are about 100 times more expensive than their counterparts on Earth due to the costly epitaxial growth manufacturing step. 

However, the solar cell team from SSPP has achieved cost-effective non-epitaxial space cells. They utilized economical and scalable production processes similar to those for silicon solar cells, employing high-performance compound semiconductor materials like gallium arsenide.

Commencing in 2013 with a substantial $100 million contribution from Donald Bren, the Chairman of Irvine Company, the initiative garnered additional support in 2015 with an injection of $17.5 million in funding from aerospace giant Northrop Grumman. 

These financial investments have propelled the project’s pursuit of groundbreaking advancements in space-based solar power technology projects.