Keeping Watch

Earth is in a danger zone. Asteroids could smack into our planet, causing massive destruction. To protect ourselves, we need to know about them well in advance. So NASA and others are scanning the skies to locate these potential killers.
Some of those efforts are based in space. NeoWise, for example, has discovered hundreds of asteroids that come close to Earth’s orbit — including more than 60 that are listed as especially threatening.
NeoWise was launched in 2009 to study the infrared universe. It shut down when it used up its coolant. But it was revived a couple of years later to look for asteroids, and it’s been working ever since. And this summer, it got a two-year extension.
NASA’s already planning its successor. Near-Earth Object Surveyor would also scan the sky in the infrared. Asteroids are dark, but they produce a lot of infrared energy, so that’s the best way to find and track them. The new craft is targeted for launch in 2026.
Scientists also are working on a plan to send a