Space-based solar power, or SBSP, refers to orbital systems that collect and harvest solar energy using solar-powered satellites ^[1]—enormous spacecraft with solar panels. Solar energy is converted into microwaves or lasers and then wirelessly transmitted via high-frequency radio waves to a fixed point on earth throughout the day. Once on the ground, a rectifying antenna, or rectenna, converts the electromagnetic energy into electricity and delivers it to the power grid for energy consumers.

The main benefit of SBSP is its higher energy collection. Because it is unaffected by the weather ^[2] or time of day, it could provide clean, reliable and efficient energy for satellites and people living in remote communities and in disaster-hit areas worldwide.

The concept of collecting solar power in space isn’t new ^[3]; however, in recent years, there’s been growing interest in developing SBSP partly due to pressure to meet national ^[4] and international climate-related goals ^[5] and achieve national space plans.

While some countries—China, Japan, India, Russia, the United Kingdom and the United States—and the European Union are in the race to develop SBSP first, the two leading countries in this competition are China and the US.

In recent decades, China has become increasingly interested in SBSP and appears to be the leader in this area. In 2008, SBSP was listed as a key research program ^[6]. In March 2016, Zhang Yulin, a national lawmaker and deputy chief of the armament development department of the Central Military Commission, said that China would make use of ^[7] the space between the earth and the moon for solar power and other industrial-development purposes. He linked SBSP to China’s national goals, declaring ^[7], ‘The earth–moon space will be strategically important for the great rejuvenation of the Chinese nation.’

In February 2019, construction of a ¥200 million ^[6] ($42 million) testing base commenced at Bishan District in Chongqing, Sichuan. The China Academy for Space Technology’s vice-president, Li Ming, stated that China expects to be the first to build a working solar power station in space  ^[8]with practical value.

Chinese scientists expect to construct small to medium-sized solar power stations to be launched into the stratosphere to produce electricity between now and 2025 ^[9] and build a megawatt-level power station in 2030 ^[9].

In June, China announced  ^[10]that it would launch an ambitious space solar power plant program ^[11] in 2028, two years ahead of the original schedule. At around the same time, researchers from Xidian University successfully tested a 75-metere-high steel structure ^[12] to divert solar power from outer space.

In the US, although NASA began researching SBSP technologies after the Apollo program ^[13] (1963–1972), the enormous projected costs meant that the idea wasn’t pursued. Nonetheless, there has been renewed interest in SBSP ^[14] over the past few decades, including at NASA.

The US Space Force has also expressed interest, and the US Department of Defense is researching SBSP for military purposes.

There is also interest in SBSP at American universities. In 2013, the California Institute of Technology established an SBSP after a donation of more than US$100 million ^[15]. Last year, the university announced plans ^[15] to launch a test array by 2023.

It is only a matter of time before SBSP is achieved, potentially creating a new age in clean energy. This could open up opportunities for collaboration as well as assist deep space exploration programs and provide an energy source for moon bases and lunar surface operations. SBSP may become key in what economist Pippa Malmgren calls ‘space-based solutions to earthbound problems’ ^[16]. For instance, the resiliency of SBSP means that it could be used as a backup energy source ^[17] in the case of power shortages, blackouts or attacks on subnational or national energy infrastructure.

However, developing SBSP is not without technical and non-technical challenges. One of the main barriers is the high cost for things like manufacturing and transportation, and the potential need for significant investment in transmission infrastructure. Other challenges to consider are the efficiency ^[18] of wireless power transmission, the vulnerability of solar panels to space debris, and the impact on the environment and people. Nonetheless, it is expected that the costs will inevitably decline given the increasing interest from private companies in this area and technological advances ^[19].

China appears to be progressing at a faster and more concerted pace. It is already a contender in the global clean energy race ^[20] and harbours ambitious space plans, and it could become the leading space power if it develops SBSP before the US and the rest of the world. That could result in SBSP becoming an essential element of China’s Belt and Road Initiative, with Beijing offering this form of clean energy to other countries ^[21] alongside opportunities for greater economic development and connectivity.

In a broader context, the increased interest in developing SBSP may extend the geopolitical domain of competition to geospatial dimensions. The growing rivalry between the US and China on earth has already resulted in competing plans to achieve scientific and economic hegemony in space, including for space-based energy, mining, manufacturing and weapons ^[22].

More importantly, perhaps, there’s also the increasing militarisation of space due to competition for military dominance. China’s People’s Liberation Army handles all space planning, and Beijing has already designated space ^[23] as a military area. China’s 2019 white paper emphasised a growing role in space for the PLA’s Air Force, and a recent report ^[24] noted that China now has the technology, hardware and knowledge to coordinate a war from space. To further support its space ambitions, China has increased the size of its total operational space fleets by around 70% ^[25].

The US–China rivalry further adds to the militarisation of space—China wants to build lunar bases by 2027 and the US by 2025. Based on their existing rivalry, competition between the countries to build bases on planets (such as Mars) is possible. In this context, it’s not unrealistic to imagine that geopolitical ^[26] and geoeconomic tensions on earth will also be found in outer space or considered an extension of terrestrial activity.