What is aj-10 engine?

The AJ-10 engine is a liquid rocket engine developed by Aerojet Rocketdyne. It is a bipropellant engine which uses Nitrogen Tetroxide (NTO) as oxidizer and UDMH as fuel. The engine has been used on a variety of spacecraft including the Delta II and Delta IV rockets, the Pioneer 10 and 11 spacecraft, the Mars Reconnaissance Orbiter, and the Dawn spacecraft. It provides around 4,400 pounds of thrust and has a specific impulse of 316 seconds. The AJ-10 engine is known for its reliability and has been in use for over five decades.