The NASA Starshade is a deployable 'origami' satellite that aims to shield a space telescope from the light of surrounding stars to allow for superior photography of exoplanets. The shade is collapsed during deployment to an inner diameter of ~4m then expands outwards via a twisting motion about it's central axis expand to over 50m in diameter.
The main focus of the model Starshade project was to analyze/achieve the kinematics of deploying a 24 sided Starshade as well as trying to integrate FEA models from Abaqus into Dymola for a signle simulation.
A Hoberman mechanism is a linkage that is deployable via a rotation about a central revolute joint. Brackets were created at each of the joints as shown to allow beam members to rotate in synch and at a specified angle. The inner solar mesh would bhe attached to the brackets and the solar pedals to the beam members.
As can be seen to the right for an octagonal Hoberman mechanism prototype of the Starshade, each of the bars open at the same rate as it expands. The rotational torque forces the mechanism open. This style of opening mechanism was very efficient for deployment, however it was found from analyzing the Dymola data, significant forces were induced in the members during deployment and further design iterations would be require to optimize the geometry.
During stowage, the exterior solar pedals would need to be wrapped around the main assembly and then 'sprung' outwards during deployment. Multiple bending scenarios were run to analyze the potential energy stored in the pedals and to create kinematic models of the bending. These bending models will be integrated into the main CATIA assembly in Dymola once further functionality is better supported.
In addition, based off the Dymola forces observed in the structural members, a deformation model was run on the brackets to observe potential failure modes. From the simulation is was determined that the clevis section needed to be reinforced in future iterations as this was the most likely area to deform during deployment.
