NASA’s ‘Intruder Alert’ system spots an asteroid heading toward Earth

While most of us were sleeping Sunday night, an asteroid zoomed past the Earth at a distance of just over 300,000 miles (about 483,000 km) – but don’t worry, because NASA’s new space rock detection system was tracking the object and knew there was virtually no chance of impact.

So what is this new technology keeping our planet safe from harm? According to NPR and other media outlets, it’s a computer program named Scout that is currently being tested at the US space agency’s NASA Jet Propulsion Laboratory (JPL) in Pasadena, California, and it constantly looks at data collected by observatories all over the world searching for nearby asteroids.

If it discovers one of these so-called “near-Earth objects,” it then quickly calculates whether the planet is in any real danger, and if so, instructs telescopes to continue monitoring the space rock. In this case, it spotted the asteroid known as 2016 UR36 on October25, giving NASA five days to prepare a response if needed – far more than they had in the past, said ScienceAlert.

“When a telescope first finds a moving object, all you know is it’s just a dot, moving on the sky,” JPL astronomer Paul Chodas told NPR. “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,” he added. Thanks to Scout, however, they now have a bit longer to prepare for a potential asteroid impact and to come up with a way to mitigate the threat.

Scout, Sentry teaming up to keep Earth safe from dangerous space rocks

In the case of 2016 UR36, the asteroid was detected on October 25 by the Panoramic Survey Telescope and Rapid Response System (PAN-STARRS) array in Maui, Hawaii, Motherboard  and ScienceAlert explained. Within 10 minutes, Scout was aware of the threat and calculated a number of different potential flight paths, some of which intersected with the Earth.

The program then proceeded to notify other observatories to conduct additional observations of the asteroid, and within a matter of hours, it had determined that the rock would fly by the planet at a distance of 310,000 miles (about 499,000 km) – meaning it would be further away than the moon. Furthermore, it determined that 2016 UR36 was between 5 and 25 meters across.

Scout, which is currently in the testing phase, could become fully operational before the end of the year, according to NPR. The main goal of the project, JPL’s Davide Farnocchia noted, is to “speed up the confirmation process” – and while five days notice may not seem like much, it is far more than the 19 hour window separating the detection of 2008 TC3 and its explosion over the Sudan in October 2008, which occurred 12 hours after it was declared a threat.

While Scout is used to detect smaller objects, NASA also uses a complementary program, known as Sentry, to keep tabs on larger potential impactors. Sentry tracks near-Earth objects larger than 140 meters in length, and has to date compiled a list of more than 650 with the potential to cause significant damage, should they reach the planet’s surface. By spotting such threats early, NASA hopes that they will have enough time to stop them and prevent catastrophic damage.

“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, “ Ed Lu, CEO of an asteroid threat organization called B612, told NPR.  “Then you can divert such an asteroid by just giving it a tiny nudge when it’s many billions of miles from hitting the Earth.”


Image credit: NASA