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MIT Technology Review

NASA wants to build a new space telescope to spot dangerous asteroids

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A near-Earth asteroid.A near-Earth asteroid.

NASA has announced plans to develop and launch a new mission to identify large asteroids orbiting close to Earth and shore up our planetary defense efforts.

What is it? The Near-Earth Object Surveillance Mission, announced on Monday, would put a 50-centimeter telescope armed with an infrared camera into orbit. The entire spacecraft would probably weigh no more than 2.5 tons, allowing it to fly on midsize rockets like the SpaceX Falcon 9 or the Atlas V. The mission, the first to specifically look for near-Earth objects, is largely based on NEOCam, a proposed infrared space telescope that NASA debated for years but never approved.

Why do we need it? In 1998, Congress tasked NASA with finding at least 90% of all near-Earth asteroids larger than 469 feet in diameter, a size that could devastate towns and cities upon impact. That goal was supposed to be met in 2020, but most experts estimate we’ve only identified about 30% of the near-Earth asteroids from this population. Close shaves by some asteroids in recent years have highlighted our blind spots. 

Our best information on near-Earth objects comes from the 10-year-old WISE/NEOWISE, originally an astrophysics mission that got a second lease on life spotting and cataloguing tens of thousands of asteroids. But that mission will probably end next year as instruments fail. The NEO Surveillance Mission could finish cataloguing the asteroid population in 10 years or so.

Waiting for the check: Congress must still approve funding for the mission before any real work can be initiated. The total cost of the mission would be $500 to $600 million, for launch in 2025. Most of the funding would be pulled from the $150 million annually allocated toward NASA’s planetary defense program, which is wrapping up work on the Double Asteroid Redirection Test launching in 2021.