|Fig. 1: Solar Impulse Technologies solar-powered plane in D.C. (Source: Wikimedia Commons)|
Solar-powered planes may potentially be a driving force to enhance the world's efforts in improving the development and use of clean energy technologies. Airplane emissions could consume a significant amount of the remaining global carbon budget. This years ICAO statistics alone indicate that international aviation is responsible for 448 million metric tons of CO2 emissions.  Further, as planes fly at high altitudes, emissions of NOx result in even greater concentrations of ozone than ground-level emissions and emissions of water vapor create condensation trails that contribute to warming. Overall, these types of statistics about current aircrafts indicate that there is a necessity to shift to more sustainable, clean technologies like solar powered planes.
Initially, some of the first solar-powered flights consisted of using 28 nickel-cadmium batteries replaced by 3,920 solar cells.  Starting in the 1980s, AeroVironment researchers experimented with solar-powered aircrafts in NASA's Dryden Flight Research Center. This research first resulted in the Social Challenger, itself able to carry 16,128 cells, while having nearly half the wingspan (46.5 feet) of the first solar-powered planes. 
This research of solar-powered planes expanded from the Solar Challenger to planes such as the Pathfinder, Pathfinder-Plus, and, currently, the Centurion. These planes have built on the successes of each other through reaching higher altitudes, modifying wingspan, and increasing the number of solar cells and produced power. From 1997 to 1998, the development of the Pathfinder to the Pathfinder Plus itself consisted of upgraded motors, more efficient solar arrays and longer wings. This resulted in the plane reaching altitudes nearly 10,000 feet higher (at 80,000 feet) and carrying an extra 68lbs of machinery. 
While NASA and its affiliates have and continue to conduct much research, Solar Impulse Clean Technologies appear to be winning the race to more effective solar-powered planes. Bertrand Piccard and Andre Borschberg, founders of Switzerland- based Solar Impulse, can be commended for the first around-the-world solar flight solely powered by the sun.  Using no fuel and emitting no pollution, this flight traveled a distance of 43,000km over 550 hours.  Further, it produces nearly unlimited energy with its lithium batteries and 17,000 solar cells - relative to some of the first solar planes like the Social Challenger that produced 540 kWh. [2,4] Other achievements include world records in the solar-powered aircraft category and longest solo flight for Andre Borschberg's flight from Japan to Hawaii - a distance of 8,924 km over nearly 118 hours.  Fig. 1 is an example of one of Solar Impulse's planes that landed in D.C.
Solar Impulse Technologies puts a substantial focus on not just solar planes, but also awareness in the field of clean energy technologies.  With the work of companies like Solar Impulse, it is the incredible large-scale accomplishments that increase the prevalence of the smaller-scale clean energy technologies that are crucial for alleviating the effects of climate change.
In 2012, commercial aircrafts emitted nearly 700 million metric tons of carbon dioxide.  With the continued research and development of solar powered planes, companies by Solar Impulse, AeroVironment, and NASA, the novelty is evident and the potential is intriguing. Much concern surrounds the realms of climate change and it is these types of developments and rapid research turnovers in the past 50 years that indicate the growing potential in air technology. Further, while the focus is on improving air technology, it in fact lends itself to findings in the fields of physics, solar power, and patterns in our world today.
© Lena Tarhuni. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 "On Board A Sustainable Future: 2016 Environmental Report," International Civil Aviation Organization, 2016.
 "Solar Power Research and Dryden," Dryden Flight Research Center, U.S. National Aeronnautics and Space Administration, FS-1998-10-0054 DFRC, October 1998.
 F. Fawzy, "Solar Impulse 2: Around the World With Zero Fuel," CNN, 26 Jul 16.
 T. Kermiolotis, "Meet the Pilots Behind the Sun-Powered Plane that Can Fly Forever," CNN, 15 Apr 14.
 A. Kharina and D. Rutherford, "Fuel Efficiency Trends for New Commercial Jet Aircraft," International Council on Clean Transportation (ICCT), August 2015.