Remote-controlled robots could one day build giant solar farms in space, according to a recent trial in the UK.

British startup Space Solar conducted the test at the UK Atomic Energy Authority's (UKAEA) facilities on the University of Oxford's Culham Campus, which hosts several fusion research initiatives.

The company used two remotely operated robotic arms to assemble a section of the support structure for its future solar power satellite. The device aims to beam the Sun's energy from space to Earth. 

According to Space Solar, the trial proved that robotics can assemble gigawatt-scale solar power satellites.

Sam Adlen, the startup's co-CEO, said the demonstration opens the door to all manner of in-space infrastructure projects.   

“This is a milestone not just for our satellite architecture, but for the future of large-scale structures in space, from data centres to energy infrastructure,” he said.

As part of its plans to build a working fusion reactor, UKAEA is developing robots for extreme industrial environments, such as maintaining future fusion power plants. The trial shows that those same machines may also show promise for cosmic applications. 

Professor Rob Buckingham, executive director of UKAEA, said building fusion reactors and structures in space shared some common challenges, such as remoteness, radiation, and extreme temperatures.

The demo suggests that fusion-hardened robotics could help automate the complex task of assembling vast solar farms in orbit.   

A solar revolution in space?

Space Solar plans to capture the Sun's energy in space, using huge satellites equipped with solar arrays that are several kilometres long and around 20 metres wide. The probes would capture the energy via microwaves and wirelessly transmit it to dedicated receiver stations on Earth, which would convert the energy into electricity.   

By 2029, Space Solar plans to commission its first 30MW demonstrator system, which would be capable of powering around 1000 homes. By the early 2030s,  the startup plans to deploy its first gigawatt-scale solar space farm. The UK Space Agency has provided grant funding for the development of the startup's first satellite.

Solar panels are theoretically capable of gathering far more energy in space than on Earth because, unhindered by the atmosphere, the intensity of sunlight is much greater. They could also beam energy from orbit 24/7, regardless of the weather on the ground. 

However, space-based solar power faces many challenges. It's currently far more expensive than ground-based solar systems — the initial development of a gigawatt-scale prototype could cost €15bn–€20bn. Then there are the potential environmental impacts. Installing a satellite of that scale could involve hundreds of separate rocket launches, contributing to atmospheric pollution. 

Nevertheless, the European Space Agency (ESA), NASA, and several startups in the UK, US, China, and Japan are all working to make space-based solar a reality.