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New tracking technology to spot smaller asteroid threats

Big asteroid

New synthetic tracking technology could find all dangerous asteroids before they reach Earth (Source: NASA/ESA)

Watching The dream of detecting every potentially dangerous near Earth asteroid could be a step closer to reality, thanks to a new technique called synthetic tracking.

A report in the Astrophysical Journal, claims the system, which combines high-speed computers and low-noise cameras, has the potential to find every near Earth object down to 10 metres in size.

Currently, only a tiny fraction, possibly as little as two per cent of the estimated quarter of a million small asteroids near Earth have been found, according to the study's lead author Dr Michael Shao of the Jet Propulsion Laboratory in California.

"Only a very small fraction of those asteroids are detectable with current techniques," says Shao.

Small dark asteroids in the 10-metre range are only discovered when they're very close to the Earth.

"When they're that close, they appear to be moving very fast, making them hard to track," says Shao.

"We think we have a new mouse trap that can detect all of them. If they fall into our field of view we will find them."

Better data

The synthetic tracking system developed by Shao and colleagues uses a 5 mega-pixel camera that can snap a hundred images a second with a very low noise-to-picture ratio.

The camera is matched with graphic processing units capable of computational rates of four teraflops (trillion operations per second), allowing a huge amount of data to be processed in real time.

The software acts as an artificial tracking system, combining data from different pixels as an object moves across the camera's line of sight.

"It lets us detect and track asteroids which would normally be too faint to see," says Shao.

It also allows better measurements to be made of their orbits.

"Up to 95 per cent of asteroids are lost because they're observable over only a short period of time," says Shao.

"The higher sensitivity [of the synthetic tracking system] means we can keep track of an object for a longer period of time as it swings by Earth, so it won't be subsequently lost."

In April 2013, Shao and colleagues successfully tested the technique on two known asteroids, 2013FQ10 and 2009BL2.

Major danger

Near Earth asteroids pose a significant threat to life on Earth, prompting a recent United Nations vote to develop an asteroid defence plan.

Several times a year, an object of the size of a small car hits Earth's atmosphere. Larger asteroids occasionally also crash into Earth, producing impact sites, such as Arizona's kilometre-wide Meteor Crater.

Another impact, off the coast of the Yucatan Peninsula in Mexico, caused a mass extinction event 65 million years ago, which wiped out 75 per cent of all life on Earth.

So far more than 10,000 near Earth asteroids have been discovered, with nearly 1000 of these objects being greater than a kilometre wide. However the smaller they are, the harder they are to detect.

The danger was highlighted a year ago, when a 17-metre wide asteroid exploded in the skies over the Russian city of Chelyabinsk injuring more than 2000 people.

Over the past five years, only about 150 near Earth asteroids in the ten metre range have been discovered.

"If we get the funding to build our ideal camera, we could increase the number of small asteroids over say seven meters, detected per night by several hundred," says Shao.

Tags: planets-and-asteroids, telescopes