Yesterday the NASA New Horizons spacecraft successfully executed a flyby of the dwarf planet Pluto, one of the Trans-Neptunian objects, to within a distance of just over 12,500 km. This outstanding achievement is recognised by the Initiative for Interstellar Studies as an important stepping stone in the march of humanity, and its ambassadors, towards the distant stars. For many years astronomers, scientists and space artists have looked up towards this distance point of light and imagined what it must be like. For the first time in history, we are about to find out.
The existence of Pluto was originally predicted in 1840 after analysing perturbations in the orbit of the planet Uranus. It was eventually discovered by Clyde Tombaugh in 1940 whilst observing from the Lowell Observatory, in Flagstaff, Arizona. Since then the object has undergone some controversy in the scientific community due to an International Astronomical Union resolution in 2006 which reclassified how a planet was defined. There were three conditions for any object to be called a planet, which is that the object must be in orbit around the Sun, that the object must be massive enough to be rounded by its own gravity and that it must have cleared the neighbourhood around its orbit. It was the third condition that caused Pluto to be renamed a Dwarf Planet and the current mission to this exciting world is sure to bring further insights onto this debate. As a fitting tribute, the New Horizons spacecraft carries around 30 grams of Clyde Tombaugh’s ashes.
Pluto is a little under twenty percent of the Earth in size, is thought to have a solid surface and takes approximately 248 years to orbit the Sun at an average orbital speed of 4.7 km/s. It is located at an Aphelion distance of nearly 49 Astronomical Units (7,311 million km) and a Perihelion distance of nearly 30 Astronomical Units (4,437 million km). One Astronomical Unit (AU) is the mean distance between the Earth the Sun (149.6 million km).
The New Horizons spacecraft was launched in 2006 as a part of the NASA New Frontiers Program, in collaboration with the Applied Physics Laboratory and the Southwest Research Institute. Its team leader is Alan Stern. It has a mass of 478 kg and is powered by a 228 Watt radioisotope thermoelectric generator. The mission has the goal of understanding the formation of the Pluto system, the Kuiper Belt and the transformation of the early Solar System. It’s science analysis will include exploration of the local moons. This information will provide vital information on the formation of our own back yard but also provide a further reference upon which to examine other stellar systems, around other stars, and to understand how they formed and evolved.
The first man made object humans ever sent into orbital space was Sputknik-1 in 1957, and here we are in 2015 only now for the first time exploring one of the distant worlds of our own Solar System, approximately 49 AU distance at an average speed of 18 km/s; although the Voyager probes went further, it was not significantly more in astronomical terms. The nearest stars are 4.3 light years, or around 270,000 AU distance, so at this rate of robotic exploration, our civilization won’t be exploring the Alpha Centauri system for well over 300,000 years. So whilst this achievement is awe inspiring, and exciting, it is also humbling at the vast challenge that still awaits us out there, in the deep ocean of the Cosmos.
The Initiative for Interstellar Studies congratulates the people and the organisations behind the New Horizons mission and we will be watching along with the millions of other people around the world, as the data comes in about the exciting discoveries yet to be made.
“We hope that the images and the new knowledge discovered, has a transformative effect on human affairs, as we once again look outwards and wonder at the shared journey which may one day lay in our future. New Horizons is an outstanding spacecraft and an outstanding mission, but a horizon of any form, reminds us of the changes we still need to make if we hope to cross it”.
— The Executive Director of i4iS, Kelvin F.Long