Design, Analytical Studies, and Realization of a SplitNut Hold-Down Mechanism for Space Applications

Abstract

The hold-downs rigidly support the appendage and the mechanism in the stowed configuration during launch as well as during landing for interplanetary missions. The release actuator uses electrical resources from the spacecrafts and facilitates release of the hold-downs in orbit. The preload imparted on hold-down depends upon the mass of the appendage. For higher preloads, the most commonly used hold-down devices comprise of pyro technique-based actuation. It may be noted that pyro devices not only induce large release shock, and it also involves replacement of the actuator after each test on ground and use of a new non-tested hardware for flight model. SMA-based actuators are also used for high preloads, but these actuators have the challenges of strict temperature control specifically on the higher side to avoid inadvertent release of the mechanism. In the present development, a new hold-down mechanism has been developed for higher preload capability which ensures minimum shock, minimum electrical resources, quick release, and wide temperature range of operation. In addition, it also ensures that no load-bearing member is consumed for the actuation and the same can be tested repeatedly before the actual flight. This paper provides the details of design and realization of split nut hold-down mechanism with specifications as given in Table 1, mathematical calculations, and its analysis using FEM method. The inputs from this paper can be used for the direct implementation of a high preload-based hold-down mechanism for large appendages. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.