The name of the space rocket that D. MATHURE was in charge of, "CRISTAL", is fictional, but chosen in accordance with the french space program of the 60s & 70s. Indeed, french space rockets before ARIANE were named after precious stones : AGATE, TOPAZE, EMERAUDE, SAPHIR, RUBIS and DIAMANT.
Some events referred to are actual events:
- Wow! signal in 1977 ;
- Tunguska event in 1908 ;
- disco mirror ball mistaken for a UFO on a expressway in France in 1988.