It officially covered half the distance to the dwarf planet

Feb 27, 2010 08:17 GMT  ·  By

On February 25, the NASA New Horizons mission finally reached one of the major milestones of its flight – namely exceeding half the distance to its target, the dwarf planet Pluto. The spacecraft, which is one of the few being propelled by a cylindrical radioisotope thermoelectric generator, or RTG, carries with it 11 kilograms (24 pounds) of plutonium-238 oxide pellets, which will provide the spacecraft with sufficient power until it reaches its destination.

This particular probe is the fastest artificial device in the Universe, 16.26 kilometers per second, or 36,373 miles per hour. This will allow it to arrive in the orbit of Pluto by 2015, by the target is so far away that it will take a total of 9 years until it is reached, Space reports.

The entire journey is scheduled to last for more than 9.5 years, NASA announces. The space probe is already 15 astronomical units (AU) away from the Sun. An AU is the equivalent of the mean distance between the Earth and the Sun, or roughly 150 million kilometers (93 million miles). It is estimated that Pluto, and the inner fringes of the Kuiper Belt, will be reached in the summer of 2015. The spacecraft will then begin the science stage of its mission, which will increase the astronomers' knowledge of the outer asteroid belt, as well as of Pluto and its moons, and their dwarf planet companions.

On Thursday, the spacecraft reached the 1.48 billion-mile (2.39 billion-km) mark, which means that it was halfway between the location of our planet in 2006 (when New Horizons launched) and the place where Pluto will be in 2015. “From here on out, we're on approach to an encounter with the Pluto system. The second half of the journey begins,” says Alan Stern, who is the principal investigator of the mission, at the Boulder, Colorado-based Southwest Research Institute. The probe is expected to pass the orbit of Uranus sometime in March, the expert adds.

Studying Pluto is very difficult on account of its great distance from the Sun. Even with the refurbished Hubble Space Telescope, the world appears as a smudge, and no clear images of it exist. Hopes are that New Horizons will be able to send back the first accurate readings of the dwarf planet, in very much the same way the Cassini mission enlightened us as to the moons and surface of Saturn.