Asteroids are some of the most ancient objects in the Solar System, relics left over from the time when the planets first started forming and evolving. For this reason, scientists are very interested in them, since they can provide clues as to how this process occurred. Most asteroids orbit the Sun in a broad belt between Mars and Jupiter, but they can be found elsewhere in the Solar System as well. NASA’s OSIRIS-REx spacecraft is now en route to one of these asteroids, called Bennu, which it will study and then bring a sample back to Earth. While on the way there, however, OSIRIS-REx will also be searching for other asteroids, called Trojans. These have regular orbits which place them either just before or just behind a planet, including Earth. The spacecraft will be on the lookout for some of these Trojans near Earth this month as it travels toward Bennu.
NASA has chosen two new missions to explore the Solar System; it was announced today during a media teleconference. The missions are part of NASA’s Discovery Program, and after the competing proposals had been narrowed down to five contenders, the final two winners were announced. Both missions, called Lucy and Psyche, will visit asteroids which have never been seen up close: multiple Trojan asteroids which share Jupiter’s orbit and the unusual metal asteroid 16 Psyche. These missions will study such objects which are relics left over from the early beginnings of the Solar System, providing new clues as to how the planets and other bodies formed. Two other mission proposals to return to Venus did not make the cut, unfortunately.