A spacecraft is disclosed, comprising a deployable spacecraft body (110) comprising a plurality of sub-systems (321-324) for controlling operations of the spacecraft, and a plurality of panels (101, 102) and a plurality of hinges (112-115) each connecting adjacent ones of the plurality of panels, the hinges being arranged to permit the plurality of panels to be folded into a stowed configuration and unfolded into a deployed configuration, wherein the plurality of sub-systems are fixed to and supported by one or more of the plurality of panels. By forming the body of the spacecraft from a deployable structure, the overall size of the spacecraft can be significantly reduced in the stowed configuration. In some embodiments, a plurality of the spacecraft in the stowed configuration can be combined into a modular spacecraft assembly prior to launch, with data and power connections between the plurality of stowed spacecraft being used to transfer power from, and data to, a payload monitoring unit on the launch vehicle.