WASHINGTON, Oct. 6 (Xinhua) -- The U.S. space agency NASA announced on Monday that it has awarded research contracts worth a total of 12.4 million U.S. dollars to six industry teams to study advanced concepts for subsonic and supersonic commercial transport aircraft that could enter service in 25 to 30 years.

    NASA's Aeronautics Research Mission Directorate selected teams led by The Boeing Company, GE Aviation, Lockheed Martin Corporation, Massachusetts Institute of Technology and Northrop Grumman to receive separate 18-month study contracts valued at approximately 2 million U.S. dollars each.

    The focus of the studies is on commercial transports that can overcome significant performance and environmental challenges for the benefit of the general public.

    The work is intended to identify key technology development needs, such as advanced airframes and propulsion systems, as well as breakthroughs that will enable such vehicles to enter service in 2030-2035.

    The vehicles represent a research and development generation known as "N+3," denoting three generations beyond the current commercial transport fleet.

    "The future of air transportation is all about protecting the environment and responding to increasing energy costs in a balanced way," said Juan Alonso, director of NASA's Fundamental Aeronautics Program at NASA's Headquarters in Washington D.C.. "We will need airplanes that are quieter and more fuel efficient, and cleaner-burning fuels to power them. We are challenging industry to introduce these new technologies without impairing the convenience, safety and security of commercial air transportation."