1. Messier D. What a ride to space costs these days. Parabolic Arc. 2017. Available from: http://www.parabolicarc.com/2017/08/18/ride-space-costs-days/ [Accessed: Jun 6, 2018]
2. Gstattenbauer GJ. Cost comparison of expendable, hybrid, and reusable launch vehicles [thesis]. Ohio: Department of the Air Force, Air University, Air Force Institute of Technology, Wright-Patterson Air Force Base; 2004
3. Spaceflight, Pricing information. 2018. Available from: http://spaceflight.com/schedule-pricing/#pricing [Accessed: Jun 6, 2018]
4. Wassmer W. The materials used in artificial satellites and space structures. Azo Materials. 2015. Available from: https://www.azom.com/article.aspx?ArticleID=12034 [Accessed: Jun 6, 2018]
5. Molitch-Hou M. Made In Space Begins 3D Printing PEI/PC on the ISS. Engineering.com. 2017. Available from: https://www.engineering.com/3DPrinting/3DPrintingArticles/ArticleID/15254/Made-In-Space-Begins-3D-Printing-PEIPC-on-the-ISS.aspx [Accessed: Jun 6, 2018]