Engine Model: AJ-60C. Designer: Aerojet. Propellants: Lox/LH2. Thrust(vac): 280.000 kN (62,940 lbf). Throttled thrust(vac): 245.000 kN (55,078 lbf). Isp: 470 sec. Burn time: 4,000 sec. Chambers: 1. Country: USA. Status: Design 2000. Aerojet (USA) announced plans on 3 October 2000 to develop a new cryogenic upper-stage engine, the AJ-60C, aimed at the very large commercial spacecraft market that is expected to develop. The engine, which could be ready for operational use by 2005 according to Aerojet, would produce 245-280 kN of thrust at a specific impulse of 470 seconds for total run times of 4,000 seconds. It would be throttlable to 25% of maximum thrust and capable of up to 25 restarts. Used in a new upper stage for the Delta-4, Atlas-5, or Ariane-5, it would enable the launch of payloads weighing 11,000 kg into a geosynchronous transfer orbit.