Object injection in geodesic conditions: In-flight and on-ground testing issues

The novel issues that concern the last step of this sequence, defined as “injection in geodesic conditions”, make this phase object of study in the field of engineering, in which multiple disciplines are involved. Different approaches are followed in these missions to perform the injection in geodesic motion phase, depending on the proof mass mechanical boundary conditions. Being recognized as a mission critical phase, different on-ground testing approaches have been developed to verify and reduce its criticality. This paper deals with the design and on-ground testing approaches of the injection in geodesic conditions phase developed in the frame of some scientific space missions, chosen as meaningful cases. Limited to the injection of free floating proof-masses, the paper does not consider other existing instruments as for example the pendulum accelerometers, in which the mass motion is constrained by mechanical links.