AJ-60A is a solid rocket booster produced by Aerojet Rocketdyne.

Up to 2020 they were used as strap-on boosters on all United Launch Alliance Atlas V rocket configurations.

The AJ-60A rocket motor was developed between 1999 and 2003 for use on the Atlas V.[2] On January 19, 2006 the New Horizons spacecraft to Pluto was launched directly into a solar-escape trajectory at 16.26 kilometers per second (58,536 km/h; 36,373 mph) from Cape Canaveral using an Atlas V version with 5 of these SRBs and Star 48B third stage.

[4][5] In 2015, ULA announced that the Atlas V will switch to new GEM 63 boosters produced by Northrop Grumman Innovation Systems.

As configured for use on Atlas V, the nozzle is fixed at a 3 degree cant away from the attachment point, but Aerojet offers a variant with thrust vectoring capability.