X-20 Dyna-Soar: Разлика между версии

# ^ Robert Z. Pearlman (2009). "NASA's new astronaut class: call them the "Chumps"". collectSPACE. http://www.collectspace.com/news/news-100809a.html. Retrieved October 8, 2009.

# ^ NASA HQ (June 29, 2009). "NASA Selects New Astronauts for Future Space Exploration". NASA. http://www.nasa.gov/astronauts/ascans2009.html. Retrieved June 29, 2009.