1 | "Why failure is the fuel for a trip to Moon". The Times of India. |
2 | "Chandrayaan-2 landing: 40% lunar missions in last 60 years failed, finds Nasa report". |
3 | Siddiqi, Asif A. (2002). "1958" (PDF). Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958–2000. Monographs in Aerospace History, No. 24. NASA History Office. pp. 17–19. |
4 | "Pioneer 0". US National Space Science Data Center. Retrieved 3 December 2013. |
5 | Wade, Mark. "Luna E-1". Encyclopedia Astronautica. Archived from the original on 22 December 2010. Retrieved 3 December 2013. |
6 | "Pioneer 1". US National Space Science Data Center. Retrieved 3 December 2013. |
7 | "Pioneer 2". US National Space Science Data Center. Retrieved 3 December 2013. |
8 | "Pioneer 3". US National Space Science Data Center. Retrieved 3 December 2013. |
9 | Siddiqi, Asif A. (2002). "1959" (PDF). Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958–2000. Monographs in Aerospace History, No. 24. NASA History Office. pp. 21–24. |
10 | "Luna 1". US National Space Science Data Center. Retrieved 3 December 2013. |