Orbital Reflectors: Extraterrestrial Tech
Solar power arrays have become a staple of today’s energy infrastructure, but as expected, they are not effective when sunlight is absent. This is a key limitation, especially because energy demand usually peaks around the dusk and dawn times of the day, when solar arrays are inactive. Some short-term storage solutions, such as lithium batteries, do exist to provide energy during this time when solar arrays are inactive, but they are also expensive: one study puts their approximate “levelized cost of storage” at $314 USD per MWh of energy stored and released. But, what if society was able to bypass this need for nighttime energy storage by enabling solar arrays to continue functioning during nighttime? This is exactly what a team of researchers at the University of Glasgow are proposing with their new Solspace project.
(Phys.org)
The overall goal of the project is to use satellites in orbit to reflect energy from the Sun down to the Earth so that they may be harvested for solar energy, even during nighttime. According to the team’s proposal, they would send multiple reflector satellites into a high, sun-synchronous orbit on a predetermined track that would cover as many significant solar farms on Earth as possible. Through aluminized Kapton hexagonal reflectors measuring 250 m (820 ft) on each side for a total of 162,380 m (1.75 million sq ft), the satellite could be steered and aimed in any direction with four control moment gyros to deliver energy to solar farms on Earth. Thus, each pass of the satellite would reflect around 34-36 MWh of energy to the surface for solar farms to harvest during nighttime. One predetermined route by the team, involving 13 large solar farms and 5 orbital reflectors, would yield approximately 284 MWh of solar energy per day.
Researchers in Scotland suggest that orbital launch costs are becoming so cheap that a large-scale facilitation of this project is imminent. The combination of the plummeting costs of putting materials in space with the advanced technologies that continue to be developed makes these ideas plausible. For instance, SpaceX 's reusable Falcon 9 rockets have dropped the price of an orbital launch down to around $1,520/kg. Elon Musk predicts that the cost will drop 90% within 2-3 years with the larger Starship rocket launching commercial services soon. One concern that has been raised is the possibility of light pollution as a result of these reflective satellites. The possibility of them disrupting typical astronomy and daylight patterns is a serious danger. However, with all the progress that has been made to develop this unorthodox method of harnessing energy, it is only a matter of time before yet another obstacle is overcome.
