NASA's OSIRIS-REx mission will leave asteroid Bennu TODAY

NASA's OSIRIS-REx mission will leave asteroid Bennu today and begin its 1.4 billion mile, two year long journey back to the Earth, the space agency confirmed. OSIRIS-REx (the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) was the first NASA mission to visit a near-Earth asteroid, survey the surface, and collect a sample to deliver to Earth. The spaceship was sent to study Bennu, an asteroid around the size of the Empire State Building and 200 million miles away, between the orbit of Earth and Mars. OSIRIS-REx gathered 2.1 ounces (60 grams) of rock and dust during its land and grab mission to the surface of the giant space rock, filling its storage compartment. It will begin its long journey home at 21:00 BST (16:00 EDT), with a live broadcast from NASA sharing the moment it fires its thrusters to push away from Bennu's orbit. If all goes to plan, OSIRIS-REx will orbit the sun twice, travelling 1.4 billion miles as it lines up with Earth, returning its samples in Utah on September 24, 2023.