The sign accompanying the engine. It reads
Pratt & Whitney developed the RL-10
engine in 1959. Since the first successful RL-10 powered Centaur rocket flight in 1963, more
than 175 RL-10s have operated in space without a failure.
|Fuel/Oxidizer:||Liquid hydrogen/liquid oxygen|
|Specific impulse:||444.4 sec|
This is a rather old sign; Pratt & Whitney issued
a press release in April of 2009 marking the launch of the 400th RL-10