An asteroid is buzzing by at just 600,000km today. But we had advance warning of the 25m chunk of rock and ice thanks to a new NASA 'intruder alert' system.

The data was quickly uploaded to NASA's experimental, automatic threat awareness software named Scout.

Within 10 minutes Scout projected potential flight paths, some of which intersected with Earth. It immediately alerted three other telescopes to help pinpoint the rock's trajectory.

The risk assessment was delivered within hours: in this case, the new asteroid was headed in our direction, but would miss us by a comfortable margin.



It's one of just 171 new near-Earth objects detected this month. Some 1550 have been found so far this year. The total known number of near-Earth objects has now topped 15,000.

What's different is we had some five days notice of its approach.

"When a telescope first finds a moving object, all you know is it's just a dot, moving on the sky," astronomer Paul Chodas of NASA's Jet Propulsion Laboratory told US National Public Radio overnight.

"You have no information about how far away it is. The more telescopes you get pointed at an object, the more data you get, and the more you're sure you are how big it is and which way it's headed. But sometimes you don't have a lot of time to make those observations."

The first incoming asteroid to be detected before it hit, 2008 TC3, was spotted 19 hours and determined to be a threat just 12 hours before exploding over an African desert.

In February 15, 2013 a 20m wide meteor exploded over Chelyabinsk, Russia, damaging hundreds of buildings and injuring more than 1000 people. It was not detected at all.

Scout was developed to improve our response time.

The software and tracking network is due to become fully operational in a few weeks.



Scout is just one of two new systems intended to help alert Earth to incoming threats.
The other is called Sentry.

Where Scout is specifically tailored to spot small, close objects, Sentry is scouring the skies for objects big enough to flatten cities.

It has already compiled a list of 655 near-Earth objects it regards as having a chance of doing substantial damage.

But current technology is believed to be only capable of detecting, and projecting their orbits forward by up to 100 years, just 25 per cent of the asteroids of the size capable of such destruction.

"If you know well in advance, and by well in advance I mean 10 years, 20 years, 30 years in advance which is something we can do, " says
CEO of asteroid threat detection B612 Foundation, Ed Lu.

"You can divert such an asteroid by just giving it a tiny nudge when it's many billions of miles from hitting the Earth."

A new telescope in Chile, the Large Synoptic Survey Telescope, is expected to boost our early warning system significantly.