Illustration showing the OSIRIS-APEX (Origins, Spectral Interpretation, Resource Identification and Security?“Apophis Explorer) spacecraft using its thrusters to disturb the surface of Apophis. Apophis is an asteroid which, in 2029, will pass Earth at a distance of around 20,000 km, closer than some of our satellites. The OSIRIS-Apex mission aims to see how Earths gravity will affect the surface, trajectory and speed of Apophis when this occurs. As well as simply observing Apophis, OSIRIS-APEX will fire its thrusters near its surface, so that scientists can study the material below the top layer of material.