The sign accompanying the LR-91 engine. It reads
Titan Second Stage Rocket Engine
The rocket engine on display here is an Aerojet-General Model LR-91 used to
power the second stage of the Titan I rocket.
The Titan I was originally developed in 1959 by the U.S. as an Intercontinental
Ballistic Missile (ICBM), and was capable of delivering an atomic warhead as
far as 6,000 miles. This engine used a combination of liquid oxygen and
kerosene (RP-1) as propellants, as did the Titan I's first stage engines. Even though the
engine was quite small in size, it was capable of delivering nearly 60,000
pounds of thrust, which is equivalent to nearly 1.4 million horsepower.
In 1962, the Titan I was upgraded to the Titan II. The new rocket used much of the
same structural and engine design of the Titan I, but incorporated nitrogen
tetroxide and aerozine-50 as propellants. Although this new combination of
fuels was highly toxic, they were stable enough at room temperatures to be
stored within the rocket for long periods of time, allowing it to be launched
at a moment's notice. The Titan I, on the other hand, used non-storable
propellants and had to be fueled just before launch.
Because of the Titan II's reliability and launch safety, NASA selected the
booster in the early 1960's to launch all of the Gemini missions into space.
With minor exceptions, the rocket performed exceptionally well during all 10
manned launches of Gemini.
Tom Stafford rode the Titan rocket into space not once, but twice, during the
Gemini VI & IX missions. During the final
boost phase, the second stage engine of the Titan II, which was similar to this
one on display, propelled Stafford and his Gemini crew mates to speeds in
excess of 17,000 mph - nearly five miles per second.
Although I am not especially familiar with the differences between the versions
of the LR-91 used in the Titan I vs. the Titan II, I believe that the Titan I
version of this engine should be outfitted with four vernier nozzles, so this
may well be a Titan II version of the LR-91.
Also, this description paints a bit of a rosy picture regarding the Titan II's
role in Gemini. As described toward the middle of Chapter 2 of On The Shoulders of
Titans: A History of Project Gemini, NASA expressed initial
interest in the Titan II simply because it was more powerful than the Atlas
used in Project Mercury; the Titan II had the additional thrust required to
send the heavier Gemini spacecraft into orbit. Chapters 6 and 7 detail some of the
challenges to be overcome before the Titan II would prove itself to be a
reliable manned launch vehicle.