Planetary securityProtecting Earth from menacing asteroids

Published 18 February 2014

Tracking near-Earth asteroids has been a significant endeavor for NASA and the broader astronomical community, which has discovered 10,713 known near-Earth objects (NEO) to date. NASA says that it is now pursuing new partnerships and collaborations in an Asteroid Grand Challenge to accelerate NASA’s existing planetary defense work, which will help find all asteroid threats to human population and know what to do about them. In parallel, NASA is developing an Asteroid Redirect Mission (ARM) — a first-ever mission to identify, capture, and redirect an asteroid to a safe orbit of Earth’s moon for future exploration by astronauts in the 2020s.

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Compilation of videos of the Chelyabinsk meteor

One year ago, on 15 February 2013, the world was witness to the dangers presented by near-Earth Objects (NEOs) when a relatively small asteroid entered Earth’s atmosphere, exploding over Chelyabinsk, Russia, and releasing more energy than a large atomic bomb. Tracking near-Earth asteroids has been a significant endeavor for NASA and the broader astronomical community, which has discovered 10,713 known near-Earth objects to date. NASA says that it is now pursuing new partnerships and collaborations in an Asteroid Grand Challenge to accelerate NASA’s existing planetary defense work, which will help find all asteroid threats to human population and know what to do about them. In parallel, NASA is developing an Asteroid Redirect Mission (ARM) — a first-ever mission to identify, capture, and redirect an asteroid to a safe orbit of Earth’s moon for future exploration by astronauts in the 2020s.

ARM will use capabilities in development, including the new Orion spacecraft and Space Launch System (SLS) rocket, and high-power Solar Electric Propulsion. The agency says that all are critical components of deep-space exploration and essential to meet NASA’s goal of sending humans to Mars in the 2030s. The mission represents an unprecedented technological feat, raising the bar for human exploration and discovery, while helping protect Earth and bringing us closer to a human mission to one of these intriguing objects.

NASA is assessing two concepts robotically to capture and redirect an asteroid mass into a stable orbit around the moon. In the first proposed concept, NASA would capture and redirect an entire very small asteroid. In the alternative concept, NASA would retrieve a large, boulder-like mass from a larger asteroid and return it to this same lunar orbit. In both cases, astronauts aboard an Orion spacecraft would then study the redirected asteroid mass in the vicinity of the moon and bring back samples.

NASA notes that very few known near-Earth objects are ARM candidates. Most known asteroids are too big to be fully captured and have orbits unsuitable for a spacecraft to redirect them into orbit around the moon. Some are so distant when discovered that their size and makeup are difficult for even our most powerful telescopes to discern. Still others could be potential targets, but go from newly discovered to out of range of NASA telescopes so quickly there is not enough time to observe them adequately.