Asteroids are rocky and metallic objects that orbit the Sun and could be very dangerous if they make impact with the earth. All systems are go for NASA to launch a first-of-its-kind mission next month.
The OSIRIS-REx probe will lift off on September 8 on its way to study the asteroid Bennu, an object that could impact Earth in the next few centuries. Not only will OSIRIS-REx produce a detailed map of Bennu’s surface, it will collect a sample of regolith from the asteroid’s surface and return it to Earth.
It will take OSIRIS-REx approximately two years to reach its target, at which time it will begin an extended 505-day surface mapping mission. This will be done from a safe distance of 5 kilometers. The data from this process will be used to help NASA decide where the sample collection will be attempted.
OSIRIS-REx will be equipped with a long sample arm that can scoop up as much as 4.4 pounds of gravel and dust from the surface of Bennu, but the process will be touchy. OSIRIS-REx will descend to 5 meters from the surface of the asteroid, being careful not to fire its thrusters too often in order to avoid contaminating the surface of the asteroid.
The sample arm has a five-second timer that will ensure the spacecraft backs off after coming in contact to avoid a crash. This is necessary because the entire operation will happen autonomously as Bennu is too far from Earth for real time control of the probe.
NASA expects the asteroid sample to be returned to Earth in 2023 for analysis. Asteroids like Bennu are believed to be time capsules of the early solar system. They contain the same organic molecules that were present when the planets formed, but these molecules are contaminated when they enter Earth’s atmosphere.
Knowing more about Bennu in particular could be of use to humanity in the mid 22nd century. That’s when there is a slim chance that Bennu could hit Earth. It’s 492 meters (roughly a third of a mile) in diameter. That’s large enough to cause significant devastation, though probably not the end of the world as we know it.