NASA's Osiris-Rex mission will not only capture asteroid Bennu – it will also help scientists learn if the rock will one day endanger Earth.
There are many reasons for studying asteroids. They could be potential mines for precious resources, such as water and heavy elements, and they contain clues that we can study to find out what the solar system is on the earliest days.
But also the great things that shake the Earth can have some catastrophic consequences. So scientists are interested in this.
Bennu is a 487.68 m wide asteroid that orbits the Sun relatively close to Earth. OSIRIS-REx, the NASA mission to study, began in September 2016 and arrived in its mission last Monday. The spacecraft carries five instruments: a camera, a LIDAR system (like a radar, but with a laser instead of radio waves) and three spectrometers that measure different wavelengths of light to determine the composition of the asteroid.
Bennu is a particularly important goal when it comes to our own survival. About every six years, it becomes relatively close to Earth ("close" in cosmic terms, but very far from any other measure). Models suggest that during her close approaches between the years 2175 and 2196, there are 2700 chances to bump us. It's still incredibly small (99.963 percent chance of failure), but Bennu is a big rock – even small chances are too big to be ignored when civilization is threatened.
Why astronomers certainly do not know if we are safe? There are many forces in question, and small differences can change chances. During close asteroid approaches, Earth's gravity will give him a run, which could move him to a collision.
In addition, there is the effect of Yarkovsky, according to a statement by Jet Propulsion Lab: uneven warming from the sun on such a light body can cause changes in its trajectory. It is not known where Bennu will go after 2135.
OSIRIS-REx and telescopes on Earth will continue to characterize the asteroid, following its path and determining how the gravity and influence of Yarkovsky will affect its trajectory. We hope the mission will produce trajectories 60 times more accurate than today's estimates, the press release said.
So what will happen if Bennu becomes a threat? Well, you do not have to worry personally because the chances are very good to be dead. Your children are also likely to be dead.
But researchers are working on several solutions. A mission dubbed Dual Asteroid Diversion Test will attempt to blast an asteroid spacecraft to cause a change in the trajectory. Perhaps we could make them asteroids.
Or, if we get enough time, maybe we can only paint one side to change how it absorbs solar radiation, using the effect of Yarkovsky in our favor.
There are plenty of data to be taken before we know what Bennu will do and many other interesting sciences to be implemented. But know that Bennu is not an asteroid that you need to worry about. Asteroids you should caring for those who have not yet been discovered.[NASA JPL]