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.
Sending human astronauts to Mars is a dream shared by many, but there are still challenges to overcome and the question of just how to accomplish it is a subject of intense debate. Some supporters advocate sending a mission directly to Mars, while others think that returning to the Moon first, for potentially beneficial training, is the way to go. Indeed, former astronaut James Lovell, who flew on two trips to the Moon, has also called for a return to the Moon first. NASA itself has stated its desire to send a crewed mission to a nearby asteroid first, instead of the Moon, going a bit farther into space than the Moon as its idea of preparation for the much longer journey to Mars. A major problem has been that NASA has still not set a firm timetable for such a mission; it wants to go to Mars, but the steps to achieving that goal are still unclear.
This coming September, a new NASA spacecraft, OSIRIS-REx, will be heading toward an asteroid to collect samples which will later be brought back to Earth. This is the first time for such a sample return mission to an asteroid by a U.S. spacecraft, but there’s also another unique aspect to this mission – artists, and space enthusiasts in general, are being invited to submit some of their work to be included onboard the spacecraft.
Looking ahead to future planetary missions, NASA has selected five new science investigations for refinement over the next year. Later, one or two of those missions will be chosen to actually be launched, perhaps as early as 2020. The selections are part of NASA’s Discovery Program, which had requested the proposals in November 2014. Initially, 27 proposals had been submitted, from which the five current finalists were chosen. The five proposals would study Venus, near-Earth objects, an unusual metallic asteroid and Trojan asteroids.
Near-Earth asteroids, also known as Near Earth Objects (NEOs), are some of the best studied space rocks in the Solar System, primarily due to the fact that they approach the orbit of Earth, making them potentially dangerous to our home planet. Now, a new study has provided evidence that at least some of them, including dark ones which are more difficult to see, originate from the oddball Euphrosyne family of dark asteroids which are at the outer edge of the main asteroid belt between Mars and Jupiter, but have highly inclined orbits well above the plane or “equator” of the Solar System.
The Dawn spacecraft left behind the giant asteroid Vesta last September, and is now en route to the even bigger dwarf planet Ceres, but scientists are still busy studying all of the data that was sent back to Earth while it was orbiting Vesta for over a year. And as often happens while exploring these new worlds, they have made a surprising discovery: long, sinuous gullies on the walls of geologically younger craters.