Prior to this phase, subsystems which make the system have been defined. Requirements and verification tests for the subsystems are laid down. Functions for each of the subsystems are identified and suitable concepts have been selected in order to achieve these functions. In the development phase, these concepts are further refined, specifically for the system to be designed. Details regarding the realization of the system have to be finalized, in this phase.

==Flow Diagrams==

One of the ways to refine the concepts is to represent the functions to be achieved in terms of flow diagrams. This is explained by the following example. The electrical subsystem is responsible to ensure the supply of power to the system. For this example, let’s assume that uninterrupted supply of 1 A current is needed at 5 V. Generation and regulation of power are functions which are to be met by the electrical subsystem. This can be represented using the following schematic: <br/><br/>

==Payload Data Management==

Planning of the development of payload data management systems is also an integral part of developing a satellite. This involves setting up a ground station (the reason to do so is given [[Role of Communications | here]] and the infrastructure required to build one is given [[Obtaining the required Infrastructure| here]]) along with a plan for the management of any data downlinked by the satellite. Such data can include health monitoring data or sensor measurements. Planning how to analyze the data beforehand can streamline the whole process of finding faults or achieving the mission. For example, Pratham’s payload of collecting data on the total electron count required the team to create a map of the electron count over the city of Mumbai after the data had been collected.