Session: 06-01-02: General Aerospace-2

Paper Number: 168023

Evaluation of Nitinol Shape Memory Alloy Actuators for a Deployable CubeSat Radiator 

Shape memory alloys (SMAs) are unique materials that can be programmed to deform at a specific temperature and return to its original orientation. These materials can be used as actuators and have garnered attention in the field of space technology. In this study, we use nitinol, a type of SMA, as an actuator for a deployable radiator on a CubeSat. The nitinol actuator is designed to deploy the radiator out by 90 degrees. This study evaluates the performance of the nitinol joints after their integration into the radiator by measuring key parameters, including the force generated by the SMA actuator, the time required for full deployment, and the final angle achieved upon deployment. These metrics were chosen to evaluate different aspects of the CubeSat's design and ensure optimal functionality. The final deployment angle is measured to ensure the radiator is deployed as close to 90 degrees out as possible, which is crucial to achieve the ideal radiator performance. The deployment time of the actuator is also recorded to ensure that the deployment occurs within a reasonable duration, which is important due to the limited energy storage available on the CubeSat. Finally, the force is recorded to ensure the CubeSat is designed to withstand accidental deployment due to heating within the spacecraft and that the radiator can open properly when needed. The actuator portion of the radiator comprises 14 nitinol joints, each 85 mm long. These joints are manufactured by wrapping the nitinol wire with double-sided tape, followed by 42 turns of nickel wire. The joints are then wrapped with Mylar to insulate them and prevent heat loss. The 42 turns of nickel wire were chosen after calculating the required length of 1.8 ft to achieve a resistance of 3 ohms with a current of 0.72 amps and a voltage of 2.12 volts. Once assembled, all the joints are bent and tested by supplying them with 1.5 watts of power to ensure they deploy simultaneously to prevent any delay in deployment once inserted into the radiator. Two different nitinols with two different transformation temperatures were tested to evaluate their impact on deployment time. The 60°C Nitinol actuator had a deployment time of 10 minutes, whereas the 40°C actuator deployed in 2 minutes. Given the faster response time of the 40°C nitinol, it was selected as the actuator for the force and angle measurements, as it better aligns with the mission's need for quick deployment.

Presenting Author: Marcos Santana California State University, Los Angeles

Presenting Author Biography: Graduate Student in Cal State LA

Authors:

Marcos Santana California State University, Los Angeles
Jim Kuo California State University, Los Angeles
John Bellardo California Polytechnic University, San Luis Obispo
Scott Roberts Jet Propulsion Laboratory
Eric Sunada Jet Propulsion Laboratory
Takuro Daimaru Jet Propulsion Laboratory