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☄️ Defend Earth (2D) — Asteroid Deflection Simulator

A top-down 2D asteroid-defence game: launch kinetic-impactor rockets or a gravity tractor to deflect incoming asteroids away from Earth, using real trajectory and impulse vector math.

Space Explorers2DEasy60 FPS📱 Mobile-adapted⇄ 3D version

A top-down 2D companion to the 3D Defend Earth game: asteroids approach Earth on straight-line trajectories from every direction, and you deflect or destroy them using two real planetary-defence strategies — kinetic impactor rockets and a gravity-tractor velocity nudge.

🔬 What It Demonstrates

Rocket mode fires a homing kinetic impactor that removes an asteroid on contact, mirroring NASA's DART mission. Tractor mode applies a perpendicular Δv impulse to the asteroid's existing velocity vector, computed with real 2D vector math — the same principle a gravitational tractor uses to gradually redirect an asteroid's orbit without destroying it.

🎮 How to Use

Click or tap an asteroid to act on it. Switch between Rocket and Tractor modes, adjust the asteroid speed and size sliders, and use Reset / New Wave to start over. The HUD shows how many asteroids you've deflected and the estimated time to the nearest impact.

💡 Did You Know?

NASA's DART mission crashed a spacecraft into asteroid Dimorphos in September 2022, changing its orbital period by 32 minutes — proof that even a small, well-timed velocity change is enough to steer an asteroid away from a collision course.

⚙ Under the hood

A top-down 2D game where you deflect asteroids heading for Earth. Launch a rocket to destroy an asteroid, or fire a gravity tractor to gently push it off course using a real perpendicular velocity impulse. Adjust asteroid speed and size, and defend Earth through increasingly difficult waves.

asteroid defenseorbital mechanicsspace gamekids sciencevector physicsdeflection

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install