Leopold Summerer, head of the Advanced Concepts Team at the European Space Agency, thinks laser beams will be better than microwaves due to their higher transmission frequencies and narrower apertures. His department has been coordinating exploratory discussions between the big European energy suppliers and aerospace companies. "By the time space solar power is ready there will already be large-scale terrestrial solar panels in place," Summerer says. "The same panels could be used to receive energy from a laser. You could save a lot of money on energy storage by beaming at night and throughout the year."
The various platforms under consideration will not be competitive until the cost of space flight goes down. NASA's budget has been shrunk and Japanese agency JAXA has suffered technical setbacks. The International Space Station barely manages to justify its running costs. As of today, none of the agencies is funding a space solar power launch. Rouge says: "This is a commercial venture. The US government could be an initial customer, but they won't be the ones to build it."
Test prototype
Solar power beaming could be much more profitable than space tourism. It has the potential to drive down launch costs, thereby making a number of other missions practicable. In a survey of the US space community's National Space Goals conducted last year, launching solar power satellites came top of the list.
Over the past 40 years, microwave and laser power transmission systems have been tested successfully in Europe, the US and Japan. Unmanned aircraft and lunar rovers receiving power from a remote beam are proven applications. The Japanese have tested reactions in the ionosphere to microwaves at the frequencies used for space solar power, and the results were positive. The only remaining issue is to test a large-scale system.
Space Island Group is a Californian startup with an ambitious strategy. Gene Meyers, its chief executive, says the company has almost completed financing for a test prototype launch at a total cost of US$200 million. "We expect to have the prototype in orbit within two years," he says. "It will be a 10 megawatt to 25 megawatt system in low Earth orbit, using a microwave beam to deliver the energy to ground stations, probably located in Europe."
Their main competitors are Mitsubishi and an as-yet unnamed European consortium. "Mitsubishi is more advanced in their satellite design, but are stymied by launch costs," Meyers says. Space Island will use NASA fuel tanks and launch facilities built in the 1970s. "They are designed to handle a launch every week, so the capacity is there to scale up to a larger system," he says. The plan is to have a 100-gigawatt service in operation by 2025.
The Indian government has expressed interest in becoming a customer. Many rural areas are undergoing development but do not have access to the national grid. There are also a large number of island nations paying excessive amounts to distribute electricity.
Leopold Summerer at the European Space Agency says: "I think we'll use the technology sooner or later. If one nation develops this service, the others will take it seriously. They won't be able to resist."
RSS