The New Horizon’s mission originally launched in 2006. Sometime between October and December of 2015 it will arrive at Pluto and provide the best views yet of the former planet. Even the New Horizons team wasn’t sure what came after that however. Not, that is, until very recently.
After trying for years to get a better look at objects in the Kuiper belt using ground telescopes, the researchers remained frustrated. They did not have a clear enough view to set New Horizons on a trajectory toward anything specific.
With time running out the New Horizon’s team was, fortunately, given time on the Hubble space telescope to look for potential targets. The Hubble data provided not one but five potential targets beyond Pluto. Of those five, two have been eliminated but the next definite target has been selected.
Potential Target 1 (PT1) was originally discovered in June, with additional data on the object arriving in August. Since that time four independent analyses have confirmed that it is a reachable target.
“…the New Horizons team will be able to choose arbitrarily how close they want to fly to the object, limited by the uncertainty in their understanding of its orbital path. Picking that distance will require balancing the desire to get high-resolution observations with engineering constraints like how fast the spacecraft can rotate at closest approach to target the object. If the object is 30 kilometers in diameter, New Horizons’ highest resolution camera, LORRI, would get 100 pixels across it at a range of 60,000 kilometers, or 1000 pixels across it at a range of 6000 kilometers,” said Emily Lakdawalla of the Planetary Society.
PT1 lies approximately 46 AU away, with one AU being the distance from the Earth to the Sun, and is estimated to be just 18 to 27 miles in diameter. Scientists believe that most objects that small are likely the result of collisions between larger objects. PT2 and PT3 are brighter in the Hubble images, which means that they may be larger. It is possible, as more data is gathered, that before New Horizons reaches Pluto, the decision will be made to abandon PT1 and chase one of the other objects. Otherwise the spacecraft will likely have a close encounter with PT1 at some point in 2019.
Regardless of which object New Horizons chases, it will be our first up close look at objects in the Kuiper belt. The Kuiper belt which lies beyond Neptune, roughly 30-50 AU away, is made up of the leftovers from the creation of our solar system. It is believed to be 20 to 200 times as massive as the Astroid Belt which lies between Mars and Jupiter.
Most of the objects in the Kuiper belt are believed to be made up of ices such as methane, ammonia and water. All together it is believed to contain more than 100,000 objects over 62 miles in diameter.
Whatever the objects are made of, they are too far from a heat source and so too cold to support life as we know it. Because the objects in the Kuiper Belt are small, cold and distant there is still a great deal that scientists do not know about them. Whatever data the New Horizons spacecraft delivers will greatly expand our understanding of the Kuiper Belt and the creation of the solar system.