Asteroids are heading for Earth!
Choose Rocket mode to shoot interceptors at them,
or
Tractor mode to gently deflect them with a real velocity nudge (Δv), just
like a gravity tractor.
You have 3 rockets. Save the planet! 🌍
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.
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.
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.
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.