Solar-powered flight may sound like something from the distant future but it is being developed and tested today. As a matter of fact, an around-the-world trip by solar power was achieved by two pilots just last year. It was completed in a little more than 500 days in an aircraft with more than 17,000 solar cells weighing in at over 4,000 pounds. The feat illustrates the possibility of someday achieving solar-powered flight on a commercial scale as materials become lighter, batteries more efficient, and electric motors more powerful. It is important for the environment as well since jet aircraft produce more greenhouse gases than just about any other machine.
The airplane was very light for its size and thus was fragile. The flight was typically conducted at night on battery power while stopping during the day to allow the solar cells to recharge the batteries. Flying at night allowed for operations to be conducted in smoother air so operations during that time were the obvious choice. It was a big feat for the burgeoning technology and it will be interesting to see what the future holds for solar flight.
Similar technologies, ones using some form of electricity, are being developed as well. Powered flight using fuel cells (using the reaction of two elements to generate electricity) is being tested. Also in the works are ultra-capacitors (high energy bursts for takeoff using supplemental energy methods) and batteries. Transmission of microwave energy is also being tested. This form of wireless energy would use ground-based stations to transmit the electrical energy to the aircraft which would then convert the energy into propulsion. It will be interesting to see what other future technologies will be incorporated into mass transit.