New York. The LLTV was a second generation vehicle, after the Lunar Landing Research Vehicle, used by NASA Apollo Program astronauts to develop piloting skills. The LLTV provided Apollo program commanders the opportunity to experience the flight characteristics associated with the 1/6 gravity conditions on the Moon. The first LLTV vehicle was assembled at Ellington Airforce Base in Houston, Texas in 1967. Three LLTV vehicles were eventually delivered to Ellington AFB. The last remaining of the three LLTV vehicles is on display at the Johnson Spacecraft Center in Houston, Texas. The electronic control system was designed with redundant channels that used 2 of 2 logic. The outputs of each primary channel were compared on a continuous basis. If a fault was detected in the primary control system, then control was automatically switched to an identical backup channel and the pilot immediately took measures to bring the vehicle to the ground. All the controls were analog circuits utilizing Burr-Brown transistor amplifier modules and other analog components. Aircraft on display Two of the five vehicles survive. LLRV-2 is on display at the Air Force Flight Test Museum at Edwards Air Force Base. It was lent to the museum by NASA in 2016. LLTV-3 (LLTV NASA 952) is on display at the Johnson Space Center. Another vehicle, a replica of NASA 952, is in a partially complete state in the aircraft boneyard at the Yanks Air Museum. See also References External links LLRV/TV flight summary (sci.space.history post) LLTV FRRB transcript Pictures Pictures Conference video from meeting where 4 Moon walkers discuss the value of the LLTV Neil Armstrong presentation on LLRV/TV (video from the 51st SETP Symposium) Apollo program hardware Bell aircraft Mixed-power aircraft NASA aircraft Rocket-powered aircraft 1960s United States experimental aircraft VTOL aircraft Aircraft related to spaceflight Aircraft first flown in 1964