MENG 185 : CubeSat

MENG 185: CubeSat

Project Goal:

As the aerospace industry tends toward a pattern of rapid design and iteration, being able to quickly, cheaply, and effectively test different heat shield designs is becoming increasingly valuable. We aimed to design a 1U CubeSat fit with Entry and Descent capabilities. Our craft will be able to deploy a heat shield and slow its descent with a deployable parachute, all while collecting thermal data to assess the performance of the heat shield. Currently, heat shields are researched and designed but only tested at Langley Research Center’s Mach 6 wind tunnel before their use in space, limiting realism in testing at a steep cost. Our design could save spacecraft manufacturers considerable time and money while working to prevent unnecessary failures during missions.

Skills Used:

Mechanical Design
CAD (OnShape)
Machining (Watter-jet, mill, bandsaw)
Mechanical modeling and analysis

Specifications:

10 cm x 10 cm x 10 cm
6061 Al exterior
Carbon fiber composite heatshield

Results and Significance:

Each of the components (thermocouple, parachute-bay door, heat shield deployment) worked successfully independently, but size constraints made a fully functional, integrated system difficult for our final design.
Spring force alone was not enough to propel the parachute from its bay.
Wiring electronics around the parachute bay presented a great challenge
Gained valuable experience with mechanical design!

Mechanical Design:

Our CubeSat had three key mechanical requirements:

Deploy the heatshield
Evaluate heatshield performance
Deploy a parachute

To address the first of these requirements, we opted to use a lead screw attached to a 6V DC motor. The motor and screw were mounted in the parachute bay box and the extended below to heatshield compartment, where it threaded through the middle of the heat shield.

The second requirement was addressed with a set of threaded thermocouples that we mounted in the heat shield with one close to the center and one close to the edge of the heatshield. The program in the Arduino Nano returned temperature data at each timestep.

The third of these requirements was met with a 3D-printed parachute bay composed of a bed of springs upon which a platform was mounted, with compartments on the side for electronics. The parachute was to be compressed by the spring bed into the door, which could be opened by activating a servo motor, releasing a latch and theoretically propelling the parachute from the bay.

Manufacturing/Assembly:

The majority of the CubeSat chassis was manufactured from 1/16" 6061 Al sheets, cute with an abrasive jet cutter. The main plates were connected bolted together with L-shaped braces cut from scrap-metal.

The parachute bay was 3D printed from PLA and the heatshield was constructed by setting a carbon fiber sheet over a solid hardened resin body with epoxy. The leadscrew had to be cut in order to fit within the CubeSat assembly.

Testing:

Our CubeSat went through two types of testing:

Functional Testing: The CubeSat was tested to see if each of its subcomponents worked. As revealed above, due to major size constraints, the subsystems did not work when integrated into the main assembly, but most worked before integration. The exception here was the parachute deployment mechanism: the available spring simply were not strong enough to propel the parachute.

Strength Testing: On the last day of MENG 185, each CubeSat is drop tested at a height of ~30ft and evaluated after collision. Our CubeSat withstood the 30 ft fall and experiences only minor scratches to the chassis.

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