Caltech/Momentus
Solar power has become the lowest cost method of generating electricity on the planet. However, building it on Earth often gets in the way of darkness and clouds, which imposes considerable limits on the amount of power it can generate. So there were always a few people who liked the idea of installing solar panels where he could generate electricity 24 hours a day, that is, in space.
This allows near 24/7 power production, but it has some very obvious drawbacks. High launch costs, unmaintainable hardware, and the challenge of returning power to where it is needed. It has been difficult to determine how these trade-offs will play out in the energy market. This is partly because the energy market is changing rapidly and partly because we don’t really know what space-based solar hardware will look like.
But thanks to some funding from private donors, Caltech researchers have quietly worked to develop the technology needed to make space-based solar power work. And thanks to the successful launch of Falcon 9 this morning, they’re apparently ready to subject some test hardware to the rigors of space.
what do we need
The Caltech team’s intended space-based power plant design is shaped by simple economics. The biggest cost is the trip to orbit where weight is a key factor. So getting the most power out of a given weight is central to that plan. This design partially limits weight by minimizing functional hardware support structures, including cabling. This is achieved by making the ‘panels’ self-contained, with their own structural supports and power transmitters. These individual panels are assembled like tiles to form a larger surface, but work independently.
That design will determine what the Caltech team will need to test: lightweight power transmitters, thin membranes that can be deployed in space, and various photovoltaic materials that can be placed in flexible membranes. And that’s exactly what they have in their test hardware universe.
The hardware includes MAPLE (Microwave Array for Power-transfer Low-orbit Experiments), a set of lightweight and flexible microwave transmitters. It can achieve the precise timing needed to send a large collection of transmitters all to a single receiver. MAPLE has two different receivers so you can test the ability to transmit directly.
DOLCE is an on-orbit deployable ultralight composite experiment that expands to cover a surface area of about 4 square meters on-orbit. It is intended to test the framework used to extend and support solar arrays in space.
DOLCE hardware in a compact form.
Caltech/Momentus
Caltech didn’t reveal what ALBA stands for, but it’s a collection of 22 different photovoltaic materials that will be used to determine which of these will survive space. .
All hardware is attached to commercial orbital transfer vehicles used to carry small satellites into their desired orbits. DOLCE testing, which consists primarily of determining whether DOLCE’s deployment was successful, should be relatively quick, with the results captured by the on-board video camera and streamed to Earth. Generally, they expect that testing of solar cell materials will take about six months in orbit before yielding definitive results.
first step
It’s not hard to see why this was done by a university team rather than a private company. Space is expensive, and we don’t even know what technology will work to generate and transmit power from orbit. It is a very risky pursuit for a private company. Based on the testing situation, it could be a long time before we can deploy an operational space-based solar power plant.
But in some ways, the timing may be right. Current estimates suggest that a very high share of renewable energy (nearly 70%) can be achieved without much difficulty. But decarbonizing the grid from that point onwards will become increasingly difficult as issues such as seasonal changes and rare weather events that dramatically reduce electricity production become increasingly difficult to manage.
Few places on the planet come close to that 70%, and few are committed to fully decarbonizing their power grids. Therefore, the coming decades will not face any difficult challenges. Space-based solar power could therefore be sorted out around the same time that the most difficult and costly steps towards decarbonisation would have to be taken.
