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Probe zooms towards Pluto
21/01/2006 09:14 - (SA)
Cape Canaveral - The fastest spacecraft ever launched began the first full day of its three-billion mile journey to Pluto, where it will study the last unexplored planet and the mysterious icy area that surrounds it.
The New Horizons spacecraft blasted off aboard an Atlas V rocket on Thursday afternoon in a spectacular start to the $700m mission. Despite the speed - it can reach 58 000km per hour - it will take 9 1/2 years to reach Pluto and the frozen, sunless reaches of the solar system.
"It looked beautiful," said Ralph McNutt jun of the Johns Hopkins University Applied Physics Laboratory, one of the mission's scientists. "I was getting a little bit antsy."
The 480kg spacecraft was loaded with seven instruments that will photograph the surfaces of Pluto and its large moon, Charon, and analyse Pluto's atmosphere. Two of the cameras, Alice and Ralph, are named for the bickering couple from TV's The Honeymooners.
Scientists to study Pluto
New Horizons also contained some of the ashes of Clyde Tombaugh, the astronomer who discovered Pluto in 1930. His widow, Patricia Tombaugh, was in tears as she watched the launch.
The National Aeronautics and Space Administration (Nasa) had postponed the liftoff two straight days because of wind gusts at the launch pad and a power outage at the spacecraft's control centre in Maryland.
Pluto is the solar system's most distant planet and the brightest body in a zone known as the Kuiper Belt, which is made up of thousands of icy, rocky objects, including tiny planets whose development was stunted for unknown reasons.
Scientists believe studying those "planetary embryos" can help them understand how planets were formed.
Some astronomers question whether Pluto is technically a planet. Pluto is a celestial oddball - an icy dwarf unlike the rocky planets of Mercury, Venus, earth and Mars and the gaseous planets of Jupiter, Saturn, Uranus and Neptune.
Launch went smoothly
Because it was launched in January, the spacecraft will be able to use Jupiter's gravity as a sling to shave five years off the trip, allowing it to arrive as early as July 2015.
The probe, powered by 11kg of plutonium, will not land on Pluto but will photograph it, analyse its atmosphere and send data back across the solar system to earth.
The launch went off without incident, to the relief of anti-nuclear activists who had feared an accident could scatter lethal radioactive material.
The probe will rely on the natural decay of the plutonium to generate electricity for its instruments. Nasa and the energy department had put the chances of a launch accident that could release radiation 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.
Nasa administrator Michael Griffin said he had an answer for those who may question spending so much on the mission to a place in space too far away to observe in any detail from earth.
"Of what value do you think it might be to be able to study the primordial constituents from which the solar system and all the planets and we, ourselves, were formed?" Griffin said.
- AP
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