Export restricted (ITAR), sale only to US Citizens and Organizations. Rocketdyne LR-101 vernier engine as used on the Atlas launch vehicle, measuring approximately 15.5˝ long and 5˝ in diameter across the nozzle, with part numbers stamped around the circumference of the upper section (several numbers obliterated). Designed to produce 1,000 pounds of thrust when operating, two LR-101s were mounted on the Atlas and Thor missiles, and on the Delta launch vehicle. On the Atlas, the LR-101 secondary engines used primarily to provide roll control after the booster engines had been jettisoned; they also contributed to thrust and, after the sustainer was shut down, powered the Atlas to its final velocity and position. The Atlas LR-101 engines can easily be seen firing in images of John Glenn's Mercury-Atlas 6 liftoff on February 20, 1962.
