This is how the Soviet attempt to upstage the US moon landing failed:
http://www.russianspaceweb.com/n1_5l.html
"On July 3, 1969, on the very eve of the Apollo-11 Moon landing,
Soviet engineers made their second clandestine attempt to fly their
giant Moon rocket. However, the mission ended just seconds after
liftoff with a colossal explosion, effectively knocking down the USSR
in the Moon Race, just days before NASA astronauts walked on the lunar
surface."