Mission analysis is the study of alternative satellite orbits to determine the best way to achieve the objectives of a space mission. This process of study of orbits and propagators is carried out during the process of definition and analysis of requirements of the different phases within one project.

At the start of a project, mission requirements are evaluated to get an overview of the different orbits that can be implemented. For each option, the information that the project needs to reach a compromise solution is studied and calculated, among the different options, that allows meeting the mission requirements. Backup alternatives are also considered and, subsequently, the chosen scenarios are evaluated in more detail. Relevant project information used in mission analysis includes: major mission milestones; the launcher’s injection orbit and mass; the delta-V budget; energy and thermal aspects, such as eclipses and distance from the Sun; the distance to Earth; the Sun-ship-Earth and Sun-Earth-ship angles and their influence on communications and payload; coverage of scientific objectives; and a qualitative assessment of complexity and operational risk.

Later, the chosen scenario is studied in more detail to demonstrate the feasibility and further optimize performance, in addition to generating all the necessary information for the platform, payload, land segment, launch and operations design. Orbit analysis includes determining the frequency of manoeuvres to keep the orbit operational and the fuel required for them, considering payload operations and ship safety. Generally, manoeuvres compensate for orbital disturbances affecting the vehicle in the selected orbit.

There are numerous tools that help mission analysis, facilitating the analysis of different elements such as instrument coverage, visibility, communications, manoeuvre analysis, constellations, etc. Systems Tool Kit (STK) is a platform to analyse and visualize complex systems in the context of a mission, which allows interaction with data from platforms in the aerospace, defence, telecommunications sectors, etc.


Cassini trajectory (source: NASA/Jet Propulsion Laboratory – Caltech)
Revisit time of the constellation Sentinel-2 (source: ESA/Sentinels-Copernicus)