1 ) An intelligent system for a spacecraft autonomous operations, comprising: (a) an on-board autonomous operations system, including: an On-Orbit Checkout Engine (OOCE) system, and an Autonomous Tasking Engine (ATE) system; (b) a Remote Intelligent Monitor System (RIMS) in communication with said on-board autonomous operations system through a communication channel, said RIMS including a user interface for Web-based communication with a plurality of user stations; and (c) a Spacecraft Command Language (SCL) infrastructure system operatively coupled to said OOCE system, ATE system, and RIMS; wherein said OOCE system collects checkout logic uploaded from said RIMS, generates SCL based checkout commands in accord with said checkout logic, and executes said SCL based checkout commands to perform a functional testing of respective components of the spacecrafts substantially upon the spacecraft reaches the orbit, and to perform a performance testing of said respective spacecraft components to monitor the operations state thereof, and wherein said ATE system receives objectives uploaded from said RIMS, plans a sequence of on-board actions to attain said objectives, generates SCL based scheduling commands for said on-board actions, and executes said SCL based scheduling commands in a predetermining order.