Space-based solar power (SBSP), which involves using satellites to capture solar energy and transmit it to collection points on Earth, has been a concept since the late 1960s. However, despite its potential, the idea has faced obstacles in terms of cost and technology. 

Is it possible to overcome these challenges? If so, SBSP could play a crucial role in transitioning from fossil fuels to renewable energy sources.

SBSP Explained

Currently, we harness solar energy through direct methods like photovoltaics (PV) and solar-thermal energy. Indirectly, wind energy is also generated by the Sun’s uneven heating of the atmosphere. 

Although these green energy sources have their benefits, they have limitations. They require large land areas and are dependent on sunlight and wind availability. For instance, solar farms don’t generate power at night and produce less during wintertime and cloudy days.

Using PV in space eliminates the limitations imposed by nightfall. Satellites placed in geostationary orbit (GEO) around 36,000 kilometers above Earth are constantly exposed to the Sun (over 99 percent of the year). This allows for uninterrupted generation of green energy.

GEO is particularly advantageous for transmitting energy from the satellite to a ground station since the satellites remain fixed relative to Earth. It’s believed that the solar power available from GEO is 100 times more than the projected global power demand by 2050.

The transfer of energy from space to the ground necessitates wireless power transmission. Microwaves are used to minimize energy loss, even under cloudy conditions. 

The satellite emits a focused microwave beam towards the ground station, where antennas convert the electromagnetic waves back into electricity. The ground station, particularly in high latitudes, would require a diameter of 5 kilometers or more.

Nevertheless, this land requirement is still smaller than what would be needed for generating equivalent power using solar or wind systems.

The Growing Interest in SBSP

SBSP could play a major role in helping governments around the world achieve net zero CO2 emissions. It could also trigger major economic growth. An independent study concluded that SBSP could create 143,000 jobs in the UK alone. 

The European Space Agency is presently evaluating the feasibility of SBSP through its SOLARIS initiative, with plans for full technology development by 2025. Several other countries have also declared their intent to transmit power to Earth by 2025, with further plans to scale up the systems in the following decades.

Aerospace Challenges

One of the key challenges in implementing space-based solar power (SBSP) is the massive amount of material that needs to be launched into space and the high cost associated with it. 

However, companies like SpaceX and Blue Origin are working on developing heavy-lift launch vehicles that can reduce costs significantly, up to 90 percent. For instance, SpaceX’s Starship vehicle has the capacity to launch 150 tonnes of cargo into low Earth orbit. 

Despite this, the SBSP satellite would still require multiple launches even with the use of such vehicles. To mitigate some of the challenges, certain components like long structural trusses could be created through 3D printing directly in space.

The Future of SBSP

Most exciting of all, SBSP could soon become a reality. 

In June, the UK government gave £4.3 million to a group of UK universities and tech companies to develop SBSP. Last January, researchers at the California Institute of Technology successfully launched solar panels into orbit. And as previously mentioned, companies like SpaceX and Blue Origin are pioneering major innovations in the aerospace industry. 

SBSP does come with a set of challenges. The impact of pollution resulting from numerous heavy-lift launches remains uncertain. Engineers working on SBSP may be forced to work with 

hazardous chemicals. Also, the powerful microwave beam required to transmit energy to the ground poses risks to anything obstructing its path. 

Nevertheless, SBSP has the potential to play a key role in achieving a net zero emissions target by 2050 by harnessing sustainable, clean energy from space.

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