A full disc view of Bennu, whoing its surface littered with giant boulders.

Asteroids, Comets & Meteors

Our solar system's small bodies pack big surprises.

Exploring asteroids


Active Missions


Mission On Deck

Rocky leftovers from planet formation.

Cosmic snowballs of gas and dust.

Bits of debris that fall through the atmosphere.

Seal shows a guard in a castle turret using a telescope to watch out for asteroids and comets in the sky.

Protect Earth from impacts.


Asteroids, comets, and meteors are chunks of rock, ice, and metal left over from the formation of our solar system 4.6 billion years ago. They are a lot like a fossil record of our early solar system. There are currently about 1.4 million known asteroids, and more than 3,900 known comets (including comet fragments).

Explore the 3D world of asteroids, comets, and NEOs. Learn about past and future missions, tracking and predicting orbits, and close approaches to Earth.

To date, NASA-sponsored surveys have provided over 95% of all Near-Earth Object discoveries.


Planetary Defense Coordination Office (PDCO)

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