![Ye-1A/5 Facts](https://webarchive.library.unt.edu/eot2008/20080921145007im_/http://solarsystem.nasa.gov/missions/images/miss-unnamed_luna_04-facts.jpg)
The launch was delayed for two days after the upper stage was accidentally filled with wrong fuel.
Failed Soviet missions often were not given names.
Cold war tensions were increasing between the Soviet Union and the U.S. as both nations launched ambitious lunar exploration efforts.