Nasa will use asteroid flyby in October to test 'planetary defence' against a real threat

Nasa will try out its response to a deadly asteroid when a small rock flies past soon.

The space agency is excited for the asteroid to fly past in October because it will give it the chance to try out what could be the most important systems in the world, should one ever fly towards the Earth.

As ever, Nasa will use the opportunity to study the asteroid from relatively close-up, taking a look at it and finding data. But at the same time they will also put those systems to the test, seeing how effectively the world can work together to keep the planet safe in the event of a deadly asteroid.

Nasa and other agencies have been working hard to co-ordinate that potential response. It relies on organisations around the world and hasn't been properly tested, and so the asteroid offers a useful opportunity.

The upcoming rock will fly past in October, is named 2012 TC4 and could be as small as 10 meters wide. Scientists don't know exactly how close it will pass by, but the Earth is safe – the nearest it is likely to get is 4,200 miles.

Scientists can't be sure because it was only spotted for a few days back in 2012. It's possible that the asteroid could actually pass much further away, as much as 170,000 miles from the surface of the Earth.

The lack of certainty about where exactly the rock will go means that it's an even better candidate for trying out how Earth will respond to a dangerous asteroid. They'll track it down as it approaches and try and work out exactly where it will fall.

"This is the perfect target for such an exercise because while we know the orbit of 2012 TC4 well enough to be absolutely certain it will not impact Earth, we haven't established its exact path just yet," said Paul Chodas, manager of Nasa's Center for Near-Earth Object Studies. "It will be incumbent upon the observatories to get a fix on the asteroid as it approaches, and work together to obtain follow-up observations than make more refined asteroid orbit determinations possible."

It's possible, if very unlikely, that at some point in the future a more dangerous asteroid could get closer to us. And scientists want to be prepared for when that will happen.

"Scientists have always appreciated knowing when an asteroid will make a close approach to and safely pass the Earth because they can make preparations to collect data to characterize and learn as much as possible about it," said Michael Kelley, program scientist and NASA Headquarters lead for the TC4 observation campaign, in a statement. "This time we are adding in another layer of effort, using this asteroid flyby to test the worldwide asteroid detection and tracking network, assessing our capability to work together in response to finding a potential real asteroid threat."

That working together takes in places across the Earth, and so it's important to see how well they can track the asteroid and communicate it as it passes.

"This is a team effort that involves more than a dozen observatories, universities and labs across the globe so we can collectively learn the strengths and limitations of our near-Earth object observation capabilities," said Vishnu Reddy, who leads the campaign to track the rock from the University of Arizona's Lunar and Planetary Laboratory in Tucson. "This effort will exercise the entire system, to include the initial and follow-up observations, precise orbit determination, and international communications."