Testing the navigation function
During my internship I produced datasets to validate the future Navigation system of the CubeSat BIRDY.
BIRDY will have to perform 3 important navigation tasks during the mission. The first one consists in orienting just after the jettison and taking the exact wanted direction. The second task is to correct the trajectory during the cruise to keep approaching Mars on a correct path. The third task, after Mars flyby, will be to correct the trajectory to ensure a right return to the Earth.
These orbit correction maneuvers (OCM) and the associated changes of orientation are sensitive. Usually a space probe performs OCM on the basis of a command sent from the Earth. Here BIRDY is too small to directly communicate with the Earth. Then an embedded navigation software has been developed that allows BIRDY to compute the necessary OCM in full autonomy without any assistance from the Earth.
It is mandatory to carefully test the navigation software. I prepared a simulation of BIRDY's orientation on its trajectory and a full test bench that produces simulated images of an embedded camera as seen from a simulated trajectory. Then I had to write a code that generates the field of view in the direction of the camera for a given orientation. These simulated fields of view will be injected into the navigation software to check whether it can react in the right way. I must say that I found it difficult to be at a central position: I needed information from colleagues such as the interplanetary orbit, the mechanical design and the spin of the spacecraft.
A main requirement was to make sure that the test bench could be transmitted to future students for further improvements. Thus I also documented every piece of code and wrote a user manual describing all parameters to be set by the user.
preparing a Master's degree of the Paris Observatory in space engineering