Pluto probe blasts off for mission to last outpost

A PIANO-SIZED spacecraft tonight blasted off on a 3-billion mile journey to study Pluto, the solar system’s last unexplored planet.

The New Horizons probe will also examine a mysterious zone of icy objects at the outer edges of the planetary system.

The probe lifted off from the Cape Canaveral air force station at 7pm, quickly reaching speeds as it pushed away from Earth of 36,000mph, which is nearly 100 times faster than a jetliner.

It was the swiftest spacecraft ever launched and was expected to reach Earth’s moon in nine hours and Jupiter in just over a year.

The distance involved means scientists won’t be able to receive data on Pluto until at least July 2015, the earliest date the mission is expected to arrive.

The launch drew attention from opponents of nuclear power because the spacecraft is powered by 24 pounds (10.8kg) of plutonium, the natural radioactive decay from which it will generate electricity for the probe’s instruments.

Nasa and the Department of Energy had estimated the probability of a launch accident that could release plutonium at 1 in 350. As a precaution, the agencies brought in 16 mobile field teams that can detect radiation and 33 air samplers and monitors.

After two delays - first because of strong winds on Tuesday at the launch pad, and then because of a power outage yesterday at the spacecraft’s control centre in Maryland - New Horizons finally got off the ground.

A successful journey to Pluto would complete an exploration of the planets started by Nasa in the early 1960s with unmanned missions to observe Mars, Mercury and Venus.

Some astronomers dispute Pluto’s right to be called a planet. It is an oddball icy dwarf unlike the rocky planets of Mercury, Venus, Earth and Mars and the gaseous planets of Jupiter, Saturn, Uranus and Neptune.