Click-Lock Deployable Booms for Rockets

ISEF Category: Engineering Technology: Statics and Dynamics

Subcategory: Other  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

A rocket part that folds, clicks, and then holds its shape can save space without staying floppy in flight. That sounds simple, but the geometry that makes a boom snap open can also make it weak after deployment. You can test that tradeoff with real data instead of guesswork. This project turns a clever mechanism into a measurable engineering problem.

What Is It?

Click-lock deployable booms are structures that stay compact for launch, then pop into a fixed shape when they open. Think of a tape measure, but with a designed snap point that locks the arm in place. The key question is not just whether the boom opens. It is whether the boom stays stiff after it opens.

Stiffness means how much a structure bends under load. If a boom sags too much, it can throw off payload alignment or deployable hardware on a rocket. You can treat the boom like a springy beam and measure how far the tip moves when you hang a weight from it. Then you can compare different printed shapes, materials, and a simple aluminum baseline.

Why This Is a Good Topic

This makes a strong science fair topic because you can change one design feature at a time and measure a clear outcome, like deflection under load. It connects to a real engineering problem in rocketry, compact storage with reliable deployment. You can build a test setup with school-level tools, collect numerical data, and use graphs, error bars, and comparison tests to back up your conclusion.

Research Questions

• How does boom wall thickness affect stiffness after deployment?
• How does the number of click-lock hinges affect tip deflection under the same load?
• What is the effect of PETG print orientation on post-deployment stiffness?
• To what extent does boom length change the load needed to produce a fixed deflection?
• Which geometry gives the best stiffness-to-mass ratio compared with a telescoping aluminum baseline?
• Does repeated deployment change the stiffness of the printed click-lock joint?

Basic Materials

• PETG filament for 3D printing.
• Access to a 3D printer.
• CAD software such as Fusion 360 or Onshape.
• Digital kitchen scale with gram resolution.
• Ruler or calipers for measuring boom dimensions.
• Clamp stand or ring stand for holding the boom during testing.
• Hanging weights or a set of small mass discs.
• Meter stick or tape measure for measuring deflection.
• Smartphone camera for documenting setup and alignment.
• Telescoping aluminum tubing or a simple aluminum rod baseline.

Advanced Materials

• PETG filament with known print settings.
• Access to a 3D printer with adjustable layer orientation and infill.
• Universal testing machine or force gauge.
• Digital calipers.
• High-resolution load cell data logger.
• Mounting fixtures that hold the boom at a fixed boundary condition.
• Aluminum tubing baseline samples with matched mass.
• Vibration or cyclic loading setup for repeated deployment testing.
• Image analysis setup for tip displacement measurement.
• Finite element analysis software such as Fusion 360 simulation or ANSYS Student.

Software & Tools

• Fusion 360: Helps you model boom geometry and compare design variants before printing.
• Onshape: Lets you build and share CAD models in a browser.
• ImageJ: Measures tip deflection from photos with a scale reference.
• Python: Organizes test data, plots load versus deflection, and compares designs.
• Google Sheets: Tracks measurements, calculates averages, and builds simple charts.

Experiment Steps

1. Define the performance target, such as maximum tip deflection under a fixed hanging load, and decide what makes one boom better than another.
2. Choose one design variable to change first, such as hinge geometry, wall thickness, or boom length, so you can isolate cause and effect.
3. Build a standard test fixture that holds every sample the same way, because boundary conditions can change stiffness results fast.
4. Plan a baseline comparison with aluminum so your printed design has a real engineering reference, not just a pass or fail label.
5. Design a measurement method for deflection and mass, then decide how you will repeat trials and handle outliers.
6. Set up a simple analysis plan with stiffness, stiffness-to-mass ratio, and a graph that compares designs side by side.

Common Pitfalls

• Printing samples with slightly different layer orientation, which changes stiffness and hides the effect of geometry.
• Letting the boom clamp slip during testing, which makes the measured deflection look larger than the sample really is.
• Comparing samples with different masses, which turns a stiffness test into a weight test.
• Measuring from the wrong reference point after deployment, which creates fake deflection differences between designs.
• Testing only one sample per design, which makes random print defects look like a real trend.

What Makes This Competitive

A stronger version of this project does more than compare a few printed shapes. It tests a clear engineering claim with matched mass, repeat trials, and a careful baseline. You can raise the level by adding a stiffness-to-weight analysis, cyclic deployment testing, or a finite element model that predicts where the boom will fail first. That gives you a design story, not just a demo.

Project Variations

• Compare PETG boom designs with PLA, nylon, or carbon-fiber-filled filament to study how material choice changes post-deployment stiffness.
• Test how print orientation changes the stiffness of the click-lock joint while keeping the outer boom shape the same.
• Compare the same click-lock concept against a folded lattice boom or a telescoping tube and analyze stiffness-to-mass ratio.

Learn More

• NASA Technical Reports Server: Search for deployable boom, space structure, and stiffness studies in aerospace engineering papers.
• NIST Materials Data Repository: Look up polymer property data for PETG and related plastics.
• PubMed: Search review articles on polymer fatigue and cyclic loading if you want background on repeated stress.
• MIT OpenCourseWare, Mechanics of Materials: Find free lecture notes on beam bending, deflection, and stiffness.
• Google Scholar: Search for recent papers on deployable structures, bistable mechanisms, and printed polymer beams.