Pass first. Then weigh in.
Structural qualification is pass/fail. Among the structures that pass every requirement, the lowest total assembled mass wins.
POE Unit 0 • Lesson 0.5
Evaluate & Develop
Focus question: How can we use engineering criteria to select the CubeSat concept most likely to be light, strong, and manufacturable?
Challenge Rules
CubeSat Lightweight Structure Challenge
Every team works inside the same architecture and material limits. Your engineering advantage comes from how efficiently you use them.
- Maximum assembled envelope: 4 in × 4 in × 4 in, including hardware.
- Top and bottom: laser cut from the team’s single 4 in × 12 in × 1/8 in acrylic sheet.
- Sides: remain open; no side panels.
- Primary frame: 3D printed using the same teacher-selected filament material for every team.
- Assembly: M3 screws for all primary structural connections; structural glue is not permitted.
- Serviceability: the structure must be able to be disassembled and reassembled with normal hand tools.
- Competition: the lightest structure that passes every qualification requirement wins.
Lesson Targets
What You Will Be Able to Do
I can compare concepts with a weighted decision matrix and develop the strongest option into a detailed design direction.
Decision Matrix + selected concept + detailed annotated sketch
The selected concept is supported by evidence-based scoring and includes enough dimensions and connection detail to begin CAD.
Activity Flow
How Today Advances the CubeSat
1. Establish selection criteria
Use strength, predicted mass, manufacturability, assembly access, and payload space.
2. Score all three concepts
Complete a weighted decision matrix and justify the scores.
3. Develop the winner
Add dimensions, M3 strategy, plate geometry, and frame details to the selected concept.
Evaluation
Recommended Decision Criteria
Teams may adjust weights with teacher approval, but the competition objective must remain dominant.
Predicted Structural Strength
Does the load path make sense? Are M3 attachment regions reinforced without unnecessary bulk?
Predicted Mass
Does the design place material only where it contributes to stiffness, stability, or connection strength?
Manufacturability
Can the parts print and laser cut reliably within the available material and class time?
Assembly & Access
Can M3 screws be installed and removed with normal hand tools?
Payload Volume
Does the design keep the interior open rather than filling it with oversized structural members?
Project Milestone
Today’s Required Deliverable
CubeSat Concept Selection Package
- Weighted decision matrix comparing all three concepts.
- Written justification for the selected design direction.
- Detailed annotated sketch of the selected concept.
- Preliminary overall and critical dimensions.
- Initial M3 connection strategy.
- List of questions that still must be resolved in CAD.
Engineering Decision
Document the Reasoning
What did your team decide today?
What measurements, requirements, comparisons, calculations, or manufacturing information support that decision?
Why does that evidence make the decision appropriate for a lightweight structure that still has to qualify?
Resources
Lesson Resources
CubeSat Unit 0 Overview
Review the complete challenge sequence, project rules, deliverables, and competition objective.
Principles of Engineering
Return to the POE hub for units, course resources, and certifications.