Space-based solar power (SBSP) is considered one of the most promising technologies for addressing Climate Change. The concept calls for satellites in Low Earth Orbit (LEO) to collect power without interruption and beam it to receiving stations on Earth. This technology circumvents the main limiting factor of solar energy, which is how it is subject to the planet’s diurnal cycle and weather. While the prospect of SBSP has been considered promising for decades, it’s only in recent years that it has become practical, thanks to the declining costs of sending payloads to space.
However, the technology has applications beyond providing Earth with abundant clean energy. The European Space Agency (ESA) is also investigating it as a means of proving power on the Moon through the “Clean Energy – New Ideas for Solar Power from Space” study, which recently yielded a technology demonstrator known as the Greater Earth Lunar Power Station (GEO-LPS). This technology could provide a steady supply of power for future operations on the Moon, which include creating a permanent lunar base like the ESA’s proposed Moon Village.
Solar power is the fastest-growing form of renewable energy and currently accounts for 3.6% of global electricity production today. This makes it the third largest source of the renewable energy market, followed by hydroelectric power and wind. These three methods are expected to grow exponentially in the coming decades, reaching 40% by 2035 and 45% by 2050. Altogether, renewables are expected to account for 90% of the energy market by mid-century, with solar accounting for roughly half. However, several technical challenges and issues need to be overcome for this transition to occur.
The main limiting factor for solar power is intermittency, meaning it can only collect power when sufficient sunlight is available. To address this, scientists have spent decades researching space-based solar power (SBSP), where satellites in orbit would collect power 24 hours a day, 365 days a year, without interruption. To develop the technology, researchers with the Space Solar Power Project (SSPP) at Caltech recently completed the first successful wireless power transfer using the Microwave Array for Power-transfer Low-orbit Experiment (MAPLE).
Exploring Mars is hazardous work. Robotic missions that are sent there have to contend with extreme temperatures, dust storms, intermittent sunlight, and rough terrain. In recent years, two robotic missions were lost due to dust alone, and all that roving around has done a number on the Curiosity rover’s treads. It’s understandable why mission teams are pleasantly surprised when their missions make it through a rough patch. This was the case with the Ingenuity team when they discovered that the rotorcraft, which has been exploring Mars alongside Perseverance, survived the night and is back in working order.
Testing how robotic helicopters fair in the Martian environment is one of the objectives of Ingenuity, which is the first mission of its kind on Mars. On May 3rd, 2022, the mission team learned that Ingenuity had lost power after trying to keep itself warm during the cold Martian night. Luckily, there was enough sunlight the following morning for the little rotorcraft to power up its batteries again and resume normal operations. This was a welcome relief, given that the Opportunity rover and InSight lander were both lost to the extreme cold and dust that characterize a Martian winter.
Solar power, long considered the leading contender among renewable energy sources, has advanced significantly over the past few decades. The cost of manufacturing and installing solar panels has dropped considerably, and efficiency has increased, making it price competitive with coal, oil, and fossil fuels. However, some barriers, like distribution and storage, still prevent solar power from being adopted more aggressively. In addition, there’s the ever-present issue of intermittency, where arrays cannot collect power in bad weather and during evenings.
These issues have led to the concept of space-based solar power (SBSP), where satellites equipped with solar arrays could gather solar energy twenty-four hours a day, seven days a week, three-hundred and sixty-five days a year. To test this method, researchers at the California Institute of Technology (Caltech) recently launched a technology demonstrator to space. It’s called the Space Solar Power Demonstrator (SSPD), which will test several key components of SBSP and evaluate the method’s ability to harvest clean energy and beam it back to Earth.
Many space-based technologies are still looking for their “killer app” – the thing that they do better than anything else and makes them indispensable to whoever needs to have that app to solve a problem. At this point in the development of humanity, most of those killer apps will involve solving a problem back on Earth. Space-based solar power satellites are certainly one of those technologies.
They have the potential to fundamentally transform the energy industry here on Earth. But they need that one “killer app” to get people interested in investing in them. A study from a group of researchers at the Colorado School of Mines looked at one potential use case – powering remote mining sites that aren’t connected to any electric grid. Unfortunately, even at those extremes, solar power satellites aren’t yet economical enough to warrant the investment.
Within the next decade, several space agencies and commercial space partners will send crewed missions to the Moon. Unlike the “footprints and flags” missions of the Apollo Era, these missions are aimed at creating a “sustained program of lunar exploration.” In other words, we’re going back to the Moon with the intent to stay, which means that infrastructure needs to be created. This includes spacecraft, landers, habitats, landing and launch pads, transportation, food, water, and power systems. As always, space agencies are looking for ways to leverage local resources to meet these needs.
This process is known as in-situ resource utilization (ISRU), which reduces costs by limiting the number of payloads that need to be launched from Earth. Thanks to new research by a team from the Tallinn University of Technology (TalTech) in Estonia, it may be possible for astronauts to produce solar cells using locally-sources regolith (moon dust) to create a promising material known as pyrite. These findings could be a game-changer for missions in the near future, which include the ESA’s Moon Village, NASA’s Artemis Program, and the Sino-Russian International Lunar Research Station (ILRS).
For years, NASA has been gearing up for its long-awaited return to the Moon with the Artemis Program. Beginning in 2025, this program will send the first astronauts (“the first woman and first person of color”) to the Moon since the end of the Apollo Era. Beyond that, NASA plans to establish the necessary infrastructure to allow for a “sustained program of lunar exploration,” such as the Lunar Gateway and the Artemis Base Camp.
Beyond these facilities, several elements are essential to ensuring a long-term human presence on the Moon. These include shelter from the elements, food, air, water, and of course, power. To address this last element, NASA has teamed up with HeroX – the leading crowdsourcing platform – to launch the NASA Watts on the Moon Challenge. This competition is entering Phase II and will award an additional $4.5 million for innovative concepts that supply power to future lunar missions.
In less than three years, astronauts will return to the Moon for the first time since the Apollo Era. As part of the Artemis Program, the purpose is not only to send crewed missions back to the lunar surface to explore and collect samples. This time around, there’s also the goal of establishing vital infrastructure (like the Lunar Gateway and a Base Camp) that will allow for “sustained lunar exploration.”
A key requirement for this ambitious plan is the provision of power, which can be difficult in regions like the South Pole-Aitken Basin – a cratered region that is permanently-shadowed. To address this, a researcher from the NASA Langley Research Center named Charles Taylor has proposed a novel concept known as “Light Bender.” Using telescope optics, this system would to capture and distribute sunlight on the Moon.
It sounds like science fiction, but building an enormous tower several kilometers high on the Lunar surface may be the best way to harness solar energy for long-term Lunar exploration. Such towers would raise solar panels above obstructing geological features on the Lunar surface, and expand the surface area available for power generation.
It is a foregone conclusion that if humanity intends to survive the so-called “Anthropocene” we need to make the transition away from fossil fuels and other methods that are unsustainable and amplify our impact on the planet. In this respect, a great deal of research and development is being directed towards “renewable energy.” Of the many methods that are being developed, the biggest contender is and always has been solar power.
Unfortunately, solar power suffers from a number of drawbacks, like the fact that it is only available during the day and favorable weather conditions. However, a new study by researchers from the Institute for Research in Electronics and Applied Physics (IREAP) shows how a special kind of photovoltaic cell could generate power at night. These “anti-solar” cells could revolutionize renewable energy and make it far more proficient.