Caltech will send a prototype orbital solar farm to orbit by December

Space-based solar power farms could harvest renewable energy from orbit 24/7.
Chris Young
solar panels
An array of small solar panels that are part of the Space Solar Power Project integrate photovoltaics, power transfer circuitry, and incorporate beam steering.


Caltech recently received a hundred-million-dollar donation to help it launch its first solar farm prototype to orbit, a New Atlas report reveals.

The researchers on the project aim to develop a technology that would be able to harvest solar power 24/7 from space. They are building state-of-the-art ultralight structures that can collect and then beam energy down to Earth from orbit.

Harvesting solar energy from orbit

The benefits of harvesting solar energy from space include the fact that the sun would shine 24/7 onto a space-based solar farm in a locked geostationary orbit.

The sun's rays are also much more intense in space than when they've made their way through Earth's upper atmosphere. This means the energy potential in space is roughly eight times better per square meter of the solar panel when compared with conditions on Earth.

Several organizations, including the European Space Agency, have recently launched programs aimed at testing the commercial viability of space-based solar power.

A team at Caltech has been working on its Space Solar Power Project for almost ten years, having launched with a $100 million donation from Irvine Company Chairman Donald Bren back in 2013. It received a further $17.5 million in funding from Northrop Grumman back in 2015.

Caltech's Space Solar Power Project

The Caltech project has been split up into three core teams. The first is working on incredibly lightweight, high-efficiency photovoltaic cells, with power-to-weight ratios roughly 50-100 times greater than solar panels used on the International Space Station.

A second team is developing low-cost, ultra-lightweight equipment that converts DC power into radio frequency power to beam it down to Earth. The third is devising methods for combining the equipment of the first two groups into massive modular space solar farms made up of thousands of tiles, measuring roughly 9 sq km (3.5 sq miles).

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These tiles — the combination of the work of the first two teams — each measure about 10 cm (3.9 in) square. They each weigh less than 2.8 g and are highly flexible, with the ability to fold up into the smallest space possible, reducing the cost of launching them into space at mass scale.

Sending a prototype solar power farm to space

The Caltech team aims to send a prototype of its space-based solar power farm to orbit in December this year. It's great progress, reflecting the substantial sum of money the Space Solar Power Project started out with.

However, logistical hurdles still stand in the way, such as the complex choice regarding which orbit to choose for its project — a geosynchronous orbit would allow it to constantly point a single receiver at a ground station on Earth, while a lower orbit would make launches cheaper, but would require multiple Earth-bound receivers. If they do unlock the potential of solar space power, they will open a new avenue for harvesting renewable energy from space without pause at a massive scale.

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