By Al Globus, NSS Board of Directors
Somewhat simplified, Space Solar Power (SSP) consists of gathering sunlight energy in space, converting this energy to microwaves, and beaming them to Earth.
This energy is freely available in Earth orbit in vast quantities.
This energy would be low carbon today, most of the carbon coming from launch, and in a future with lunar or asteroid materials the space component would put almost no burden on Earth’s environment.
Outages would be rare, short, and completely predictable far in advance. This helps make SSP energy suitable for base load energy requirements.
Until recently studies of SSP all came to the same conclusion: SSP is technically feasible but the cost of energy would be far greater than for terrestrial systems.
The cost factor appears about to change. Multiple orders of magnitude reduction in SSP costs are projected over the next decade or two, given reasonable levels of research and development. This flows from three critical areas: launch, hyper modular designs, and robotic assembly inspection and repair:
1. Launch cost. A new generation of large reusable boosters, especially the SpaceX Super Heavy in test now, are projected to be multiple orders of magnitude less expensive than the space shuttle was per kg launched to Low Earth Orbit (LEO). This is achieved by reusing essentially all of the vehicle, assembly-line-like production, and using a very large booster. Large boosters are generally cheaper per kg than small ones. The next few years are quite likely to drop launch costs from around $10,000 to $20,000 per kilogram in the shuttle era to perhaps as little as an aspirational $100/kg with the SpaceX Super Heavy Booster. Even if off by a great deal this would still revolutionize SSP costs.
2. Hyper modular systems. Hyper modular systems consist of very large numbers of modules of a small number of types. As an example, large communication satellite constellations use many thousands of small satellites as opposed to a few large powerful ones. In this case the modules are the small satellites. Back of the envelope calculations suggest that at least one constellation of small modular satellites under construction is about 100x less expensive per kg to manufacture than large non-modular communication satellites. This is achieved by taking advantage of economies of scale when producing thousands or even millions of identical modules. This can support orders of magnitude manufacturing cost reduction via automation in a factory environment rather than hand work in a laboratory-like environment. Some modern designs for SSP satellites involve in-space assembly of up to two million modules for a single 2GW SSP satellite. This, in turn, supports economies of scale in manufacturing the modules even for a single SSP satellite, at least for the most numerous module types. A fleet of SSP satellites would involve hundreds of millions of modules.
3. Robotic assembly, inspection, and repair. The current state of the art in satellite in-space construction is teleoperation of large robotic arms on the ISS (International Space Station). This works well but must be combined with space suited astronauts to do what the robots currently cannot. People are notoriously expensive to maintain in space so improving robotics to the point of eliminating the human EVA (Extravehicular Activity) and on-orbit teleoperation can be expected to have a large positive effect on SSP cost. Large SSP satellites can utilize a carefully designed workspace to facilitate automated robotic operations. This eases the design requirements for the assembly robots because the resulting tasks are relatively simple, just as the tasks for automated warehouses with driverless forklifts are much simpler than for driverless cars on public roadways.
There are many other aspects of SSP cost that are not explored here. The intent is to identify the big drivers where order of magnitude improvement may be available. If all goes well the next decade or so may be very exciting. If SSP development succeeds the activity will likely spark huge development of orbital infrastructure and bring great power and wealth to whomever plays a valuable role.
Oh yeah, there will also be vast supplies of clean, inexpensive energy for everyone too.