1. Chang, K. (2017). “Opportunity in Orbit,” New York Times, November 28.
2. Chang, K. (2010). “Boeing Plans to Fly Tourists Beyond Earth,” New York Times, September 16.
3. Hough, J. (2019). “The Space Economy Is Starting to Take Shape 50 Years After the Moon Landing,” Barron’s, July 13.
4. Lee, D. P. (2013). “Welcome to the Real Space Age,” New York Magazine, May 27.
5. Seedhouse, E. (2014). Tourists in Space: A Practical Guide, 2nd ed., Heidelberg: Springer//Praxis.