Wells CUBESAT

Last crawled date: 1 year, 12 months ago

-Summary-
The Wells CubeSat consists of a 1-piece, ribbed isogrid, 3D printable structure that is capable of withstanding the environments associated with spaceflight (random vibration, thermal, etc.). The design meets the technical requirements given in the “CubeSat Design Specifications” and uses current materials that are available for additive manufacturing.

The Wells CubeSat was specifically designed to:
1. Reduce the overall part count by designing a 1-piece unibody structure, allowing for a more simplified producibility using materials that are commercially available, reducing overall cost.
2. Reduce the weight of the structure while maintaining enough strength to survive the environmental requirements.
3. Create a structure that would reduce the CubeSat payload environment by reducing the loads generated by the vehicle and qualification random vibration environments.

-Material & Additive Manufacturing Technique-
This design was intended to utilize printed Ultem 2300 using the Fused Deposition Modeling additive manufacturing technique. Ultem 2300 is an extruded 30% glass reinforced polyetherimide. The glass reinforcement yields a product with an exceptional strength-to-weight ratio while at elevated temperatures with long-term heat resistance. Ultem can also be further reinforced with conductive fibers, or plated for EMI resistance. Ultem meets ASTME595 outgassing requirements, UL94 flammability requirements as well as zero halogen outgassing requirements.

-Design-
To maintain a 1-piece unibody design, an access door was created using a 3D printed hinge. This hinged access door allows full access to the electronics to simplify the PCB mounting installation. After the electronics are mounted, the hinged access door is secured by snap-fit connections as well as two (2) 4-40 flathead machine screws. This design also implements a ribbed-stiffened isogrid structure to maintain a lightweight structure while possessing a strength-to-weight ratio to meet the launch vehicle payload environmental requirements. Isogrid structures are generally used for space applications but are commonly machined out of a single plate of material. By 3D printing the isogrid structure, the majority of the stiffness and strength is maintained while reducing material cost and weight. Considerations were made during the design phase so that the structure can be built without support material, reducing cost, time and post processing.

Design Specifications
Ultem 2300 Density = 1.51 g/cm^2
Build Volume = 102.79 cm^3
Structure Mass = 155 grams

-Random Vibration Reduction-
A major benefit of using composite thermoplastics is reduced vibration excitation through damping. Polymer plastics are less subject to harmonic resonance than metallic structures, reducing the overall load experienced by the CubeSat payload when subjected to vehicle and component qualification random vibration environments, reducing overall design and testing costs. A preliminary quasi-static strength assessment using the predicted 3-sigma acceleration environment generated from the qualification random vibration environment (50 g’s peak) shows positive margin, providing design feasibility.