Virtus Solis to Utilize Starship for Space Solar Arrays
Virtus Solis, a Michigan-based startup founded by former SpaceX rocket engineer John Bucknell, presented its plans for space-based solar power transmission at the International Space Power Conference in London in mid-April, Space reported on April 30. SpaceX's Starship rocket will change the game for space-based solar power production, enabling orbiting power stations to be far less expensive than many terrestrial methods, according to Virtus Solis.
Concept and Advantages
Virtus Solis' concept involves deploying kilometer-wide solar arrays into orbit that can generate and transmit electricity through space. Satellite launch costs have decreased dramatically in recent years due to reusable rockets pioneered by SpaceX. While the company currently charges just under $3,000 per kilogram of payload, this is still too high for space-based solar, which requires vast solar panels that would dwarf the International Space Station (ISS).
SpaceX has pledged that once its Starship rocket becomes fully operational, launch costs will fall to $10 per kilogram. While this estimate may be optimistic, Bucknell argues that once launch costs to low Earth orbit fall below $200 per kilogram, space-based solar will become cheaper than electricity from terrestrial nuclear, coal, or natural gas plants.
Terrestrial Energy Challenges
Currently, solar panels on Earth provide the cheapest form of electricity, at under $30 per megawatt-hour. However, the sun does not shine at night, and power planners struggle to fill the gap with other renewable energy sources. To date, nuclear, coal, and gas plants have provided the necessary backup power for times when the sun is down or when the weather is unfavorable. However, thermal power plants undermine global emissions reduction goals, while nuclear is significantly more expensive.
"Nuclear power costs around $150 to $200 per megawatt-hour. Our system could ultimately do the same thing for about $30 per megawatt-hour, at scale," says Bucknell.
Virtus Solis' Plans
Virtus Solis intends to build kilometer-wide solar panels that can be assembled in orbit by robots from 1.6-meter-wide modules. Hundreds of these modules could be launched into a Molniya orbit by a single Starship launch. This elliptical orbit has its closest point 800 kilometers above Earth and its furthest point 35,000 kilometers away.
A satellite in this orbit takes 12 hours to complete one orbit of the planet. However, due to the nature of the orbit, the craft can spend more than 11 hours at the furthest point. As a result, a constellation of two or more satellites could provide constant baseline power to a region. A system with 16 solar arrays would provide global coverage, beaming energy via microwaves to giant receiving antennas on the ground.
According to Bucknell, the company is working on improving the efficiency of wireless power transmission, a key challenge for space-based solar power generation. Current systems have efficiencies of around 5%, but for practical use, this needs to increase to 20%. In February, Virtus Solis announced plans for a 2027 test satellite to demonstrate solar array assembly in space and transmit over a kilowatt of power back to Earth. The company hopes to build a megawatt-scale commercial solar power plant by 2030.