AJ10

The AJ10 is a hypergolic rocket engine manufactured by Aerojet Rocketdyne (previously Aerojet). It has been used to propel the upper stages of several launch vehicles, including the Delta II and Titan III. It is intended for use as the main engine of NASA's Orion capsule.

Variants

It was first used in the Able second stage of the Vanguard rocket, in the AJ10-118 configuration. It was initially fueled by nitric acid and UDMH. An AJ10 engine was first fired in flight during the third Vanguard launch, on 17 March 1958, which successfully placed the Vanguard 1 satellite into orbit.

The AJ10-101 engine was used on an uprated version of the Able, used on Atlas-Able and Thor-Able rockets. The first flight, of a Thor-Able, occurred on 23 April 1958, however the Thor failed before the upper stage fired. The second flight, which saw the first firing of an AJ10-101 engine, occurred on 10 July 1958.

The AJ10-118F engine produces 4.08 tonnes of thrust and was derived from the AJ10-138 engine used on Transtage. Used in Delta 1000 ("Straight Eight") series.
This version used Aerozine 50 (a 50-50 mix of UDMH and hydrazine) as fuel and nitrogen tetroxide (N₂O₄) as oxidizer, rather than the previous nitric acid/UDMH.