1. Shape Memory Alloy Reusable Deployment Mechanism
SMARD, REXUS
Shape Memory Alloy Reusable Deployment Mechanism
„Develop and verify a solar panel hold down release mechanism for a CubeSat using shape memory alloys on REXUS 18.“
MOVE II
REXUS
Length: 5.6m ∅: 35.6cm
Payload Mass: 40kg
2 min with reduced gravity
REXUS is an unguided, spin-stabilised, solid-propellant, single stage rocket. Each flight carries a payload consisting solely of student experiments.
10cm x 10cm x 30cm
Mass: 3.9kg
MOVE II is a 3 Unit CubeSat satellite developed by students in cooperation with the Institute of Astronautics at the Technische Universität München.
Structure
Electronics
Software
Solar Panel
ERIS
sbRIO-9626
Expansion Boards
HDRM
Magnetic Rotatory
Encoder
Accelerometer
Overview Software
Camera
The software is programmed using LabVIEW 2013 and controls the experiment via a state machine. Transitions between the different states will be triggered by signals received from the rocket’s service module. The experiment initiates with a boot process shortly before launch. The data gathering loop and sensors will be activated shortly before launch and kept active until landing. The telemetry uses the sbRIO's native RS485 interface, transmitting housekeeping data and a subset of the experiment data to the ground as a backup via the rocket’s communication system. All of the generated data is stored on an on-board SD-card for post-flight analysis.
SMAs are able to “remember” their original shape. In the cold state, SMAs can be deformed and stay in this form. When they are heated above a certain temperature they will return to their pre-deformed shape. This effect is due to a change in the crystalline structure of the metal.
The experiment control system ERIS is based on a National Instruments sbRIO Its FPGA is used for sensor data acquisition of accelerometers and a rotary position encoder at high data rates of up to 10kHz. The acquired data is then transferred to the real-time target. Finally the data is stored on the onboard SD-card and encoded to a format suitable for the REXUS telemetry link. The real-time target also controls the GoPro camera.
SMA Spring
Cold State
Hot State
HDRM