NASA Launches Mission to Help Assess Asteroid Impact Threat

There's been a lot of talk in the news about the asteroid set to zoom by Earth on February 15. And now NASA is assessing the hazards of asteroid impact. Every year, sensors designed to detect nuclear explosions view harmless bursts in the Earth's upper atmosphere from the breakup of an asteroid a few yards across. Yet others have a potential for destructive devastation. NASA's Near-Earth Object observations program supports surveys which are searching to find the largest objects in space and predict their impact threat to Earth.

There are currently more than 1,300 potentially hazardous asteroids (PHAs) about 150 yards across that have a small chance of making an impact. Their orbital paths will take them close to Earth, but there's no guarantee that they'll crash land. Since asteroids move so quickly--about 27,000 to 33,000 miles per hour--relative to Earth, they carry enormous energy, which is why scientists are trying to find better ways to track these asteroids.

Yet tracking asteroids isn't easy. When one of these giants makes a close pass to Earth, the gravitational pull from our planet changes the asteroid's orbit. That means that further calculations are required to see whether or not the asteroid will actually collide. In addition, smaller forces continually pull on the asteroid to change its orbit. The most significant of these, the Yarkovsky effect, is a minute push that occurs when the asteroid is warmed by the sun and then later re-radiates this heat in a different direction as infrared radiation.

Now NASA has started its OSIRIS-Rex mission (Origins, Spectral Interpretation, Resource Identification, Security, and Regolith Explorer), which will make the most precise measurements of the Yarkovsky effect to date. The mission will visit an asteroid known as "199 RQ36" in order to take measurements. Since the giant body is slated to pass near Earth's orbit, it's doubly important to make these measurements--especially since it currently possesses one of the highest probabilities of impacting our planet.

The mission is scheduled for launch in 2016, and OSIRIS-Rex will officially arrive at the asteroid in 2018. It will then orbit the asteroid until 2021, making measurements as it communicates continuously with a spacecraft in orbit.

This mission will hopefully allow researchers to better understand the Yarkovsky effect, and let them learn how to better predict the trajectory of future asteroids.