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 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, 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 reaching orbit, and to perform a performance testing of said respective spacecraft components to monitor an operations state thereof, and wherein said ATE system receives objectives, 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.