Satellite Services

Mission Goal

Design a recovery system that slows descent using autorotation (a spinning rotor or “seedpod” concept) instead of a parachute. Your goal is stable, repeatable descent with reduced impact.

Why it matters

Autorotation is a real aerodynamic recovery strategy: from helicopters (emergency descent) to seed dispersal in nature. It can be more reliable than parachutes in some conditions because it resists line tangles and can self-stabilise.

Inputs from other teams

• Payload/Data team: mass limit; where the center of mass must sit
• Structures team: how to build a strong hub and rotor mount
• Materials team: light, stiff rotor materials (card, thin plastic, balsa if allowed)
• Mission Control: standard timing + stability scoring method

Design rules

• Coordination & optimisation: you’ll balance rotor size, stiffness, mass placement, and safety.
• Trade-offs: bigger rotors slow more but can break; more blades stabilise but add drag/weight.
• Measure: time-from-height + stability score (wobble/spin consistency).

Shared Space.craft.ed challenge principles apply. :contentReference[oaicite:4]{index=4}

Build steps

1. Choose a rotor concept: 2-blade, 3-blade, or “maple seed” single wing.
2. Create a hub: central point where blades attach; reinforce with layered card/tape.
3. Set blade pitch/twist: slight angle so airflow causes spin (you can twist gently or fold a leading edge).
4. Place the mass: payload mass below the rotor/hub to act like a pendulum and stabilise.
5. Reinforce edges: tape leading edges to prevent tearing and keep shape.
6. Label variants: Rotor A, Rotor B (one change at a time).

Test protocol

1. Indoor first: low wind; 1.5 m height; 5 trials to check consistent spin-up.
2. Timing: use video or stopwatch from a known height; record times.
3. Stability score: 0–3 scale (0 = tumble, 1 = unstable wobble, 2 = mostly stable spin, 3 = stable spin entire descent).
4. Iterate: change only one variable (blade length OR pitch OR number of blades).
5. Durability check: inspect after each drop; record damage type.

Success criteria

• Stable autorotation (average stability score ≥ 2) across 5 trials.
• Descent time consistently longer than baseline drop from same height.
• Rotor survives repeated tests without catastrophic failure.

Evidence checklist

• Photo/diagram with blade dimensions and pitch method.
• Mass location description (where the center of mass sits relative to rotor).
• Timing data (height, time, average).
• Stability scoring table (5 trials) + brief notes.
• Video showing consistent spin-up.

Safety

• No sharp blades; round corners and tape edges.
• No high-speed launches; only drops (no throwing).
• Keep clear of faces; spinning rotors can poke eyes.

Common failure modes

• No pitch: rotor doesn’t spin; it tumbles.
• Mass too high: system flips and becomes unstable.
• Rotor too flexible: blades deform and stall.
• Asymmetry: uneven blades cause wobble and fast descent.

Stretch goals

• Compare 2-blade vs 3-blade and justify which you choose for “mission reliability.”
• Add a simple “shock foot” on the bottom and measure reduced bounce.
• Teach another team your build method and see if they can reproduce your result.