In January 2023, the Caltech Space Solar Power Project (SSPP) is preparing to launch into orbit a prototype, called the Space Solar Power Demonstrator (SSPD), that will test several key components of an ambitious plan to harvest solar power in space and beam. Energy return to Earth.
Space solar power provides a way to take advantage of the practically unlimited supply of solar energy in outer space, where power is constantly available without exposure to day-night cycles, seasons, and cloud cover.
The launch, currently scheduled for early January, marks a major milestone in the project and promises to make what was once science fiction a reality. When fully realized, SSPP will deploy a constellation of modular spacecraft that collect sunlight and convert it into electricity, then wirelessly transmit that electricity over long distances wherever it’s needed — including places that don’t currently have access to reliable power.
The Momentus Vigoride spacecraft carried aboard a SpaceX rocket on the Transporter-6 SSPD mission will carry the 50-kilogram SSPD into space. It consists of three main experiments, each tasked with testing a different key technology for the project:
- nicely (Experience an Orbit Deployable Ultralight Vehicle): A 6-foot-by-6-foot structure demonstrating the architecture, packing system, and deployment mechanisms of the modular spacecraft that will eventually form a kilometer-scale constellation forming a power plant;
- Alba: an array of 22 different photovoltaic (PV) cell types, to enable the evaluation of which cell types are most effective in the harsh environment of space;
- Maple (Microwave Array Energy Transfer Low Orbit Experiment): An array of flexible, lightweight microwave energy transmitters with precise timing control that selectively focuses energy on two different receivers to demonstrate wireless energy transmission over a distance in space.
An additional fourth component of the SSPD is a box of electronics that interacts with Vigoride’s computer and controls the three experiments.
SSPP began in 2011 after philanthropist Donald Brin, president of Irvine and a life member of the Caltech Board of Trustees, learned about the potential of space solar manufacturing in an article in the journal popular science. Intrigued by the potential of space solar power, Brin reached out to then-Caltech President Jean Le Chameau to discuss establishing a space-based solar research project. In 2013, Brin and his wife, Brigitte Brin, a Caltech trustee, agreed to make a donation to fund the project. The first donations (which would eventually exceed $100 million) were made that year through the Donald Brin Foundation, and the search began.
“I’ve dreamed for many years how space-based solar power could solve some of the most pressing challenges facing humanity,” says Brin. “Today, I am excited to support the brilliant Caltech scientists as they race to make this dream come true.”
It will take about 10 minutes for the rocket to reach the desired altitude. The Momentus spacecraft will then be deployed from the rocket into orbit. The Caltech team on Earth plans to begin conducting their SSPD experiments within a few weeks of launch.
Some test items will be done quickly. “We plan to lead the deployment of DOLCE within days of SSPD reaching Momentus. We should know immediately if DOLCE is working,” says Sergio Pellegrino, Caltech’s Joyce and Kent Cressa Professor of Aerospace and Civil Engineering and co-director of SSPP. Pellegrino is also a senior research scientist at the Jet Propulsion Laboratory, which is managed by the California Institute of Technology for NASA.
Other items will require more time. The photovoltaic array will need six months of testing to give new insights into what types of photovoltaic technology are best for this application. MAPLE involves a series of experiments, from initial validation of functionality to evaluation of system performance in different environments over time. Meanwhile, two cameras on DOLCE-mounted, deployable arms and additional cameras in the electronics box will monitor the progress of the experiment, feeding back to the ground. The SSPP team hopes to have a full assessment of SSPD’s performance within a few months of launch.
Numerous challenges remain: Nothing is foolproof about conducting an experiment in space—from launch to deployment of the spacecraft to operation of the SSPD. But no matter what happens, the sheer ability to create a space-worthy prototype is a significant achievement for the SSPP team.
“No matter what happens, this prototype is a huge step forward,” says Ali Hajimiri, professor of electrical and biomedical engineering at Caltech and co-director of SSPP. “It works here on Earth, and has passed the rigorous steps required for anything launched into space. There are still many risks involved, but having gone through the whole process has taught us valuable lessons. We believe the space trials will provide us with a lot of additional useful information that will guide the project as we continue.” moving forward “.
Although solar cells have been on Earth since the late 19th century and currently generate about 4 percent of the world’s electricity (in addition to powering the International Space Station), everything about solar power generation and transmission needs to be reconsidered for its widespread use in a vacuum. . Solar panels are bulky and heavy, which makes them expensive to launch, and they require extensive wiring to transmit power. To overcome these challenges, the SSPP team had to conceive and create new technologies, structures, materials, and structures for a system capable of practical realization of solar energy in space, while being light enough to be cost-effective for bulk deployment in space, and robust enough to withstand the harsh space environment.
DOLCE demonstrates a new architecture for solar-powered spacecraft and phased antenna arrays. It exploits the latest generation of ultra-thin composite materials to achieve unprecedented packaging efficiency and flexibility. “With the additional advances we’ve already begun working on, we anticipate applications for a variety of future space missions,” says Pellegrino.
“The entire flexible MAPLE suite, along with its core wireless power transmission electronics chipset and transmission elements, was designed from the ground up. This wasn’t made from elements you could buy because they weren’t there to begin with. A fundamental rethinking of the system from the ground up is necessary to achieve Scalable solutions for SSPP.
The complete set of three prototypes was conceived, designed, built and tested within SSPD by a team of approximately 35 individuals. “This was achieved with a smaller team and with far fewer resources than would be available in an industrial setting, rather than an academic one. The highly talented individuals on our team made this possible,” says Hajimeri.
However, these individuals—a group of graduate students, postdocs, and research scientists—now represent the cutting edge of the burgeoning field of space solar. says Harry Attwater, SSPP researcher, Caltech’s Otis Booth Chair in the Department of Engineering and Applied Sciences, the Howard Hughes Professor of Physics and Materials Science, and director of the Liquid Sunlight Alliance, a research institute dedicated to using sunlight to make liquid products that can be used for industrial chemicals, fuels, and materials. construction or products.
The success or failure of the three test rules will be measured in several ways. The most important test for DOLCE is that the structure fully deploys from its folded to open configuration. For ALBA, successful testing will provide an assessment of photovoltaic cells operating at maximum efficiency and flexibility. The goal of MAPLE is to demonstrate the selective transfer of energy in free space to various specific targets on demand.
“Often, we’ve asked colleagues at JPL and in the Southern California aerospace industry for advice on the design and test procedures used to develop successful missions. We’ve tried to minimize the risk of failure, even though developing entirely new technologies is inherently a risky process. says Pellegrino.
SSPP ultimately aims to produce a global supply of affordable, clean, renewable energy. More about SSPP can be found on the program’s website.