Nasa waits on Deep Impact
2005-07-03 20:01
Washington - Scientists on Sunday nervously awaited news of whether the first-ever projectile shot at a passing comet will hit its mark, allowing them to peer into core of the celestial body.
Nasa scientists early on Sunday fired the "Deep Impact" probe toward the comet Tempel 1, hoping to gain a unique glimpse beneath the surface of the comet and gain new clues about the origins of the solar system.
The collision could produce a brilliant light show visible from Earth with binoculars - or could yield a poof of dust, if the comet proves to be just a loose pile of rubble, as some experts suspect.
It will be early Monday morning, just before 0600 GMT, before officials know if the probe's broadside is a hit or miss.
Similarities
Although there are faint similarities with the 1998 movie "Deep Impact", in which a US spaceship attacks an errant comet with nuclear weapons to ward off its collision with Earth, the probe hurtling toward comet Tempel 1 was launched purely in pursuit of scientific goals, space officials said.
"The impact simply will not appreciably modify the comet's orbital path," said Don Yeomans, a mission scientist with Nasa's Jet Propulsion Laboratory.
"Comet Tempel 1 poses no threat to the Earth now or in the foreseeable future," he said.
The 333-million-dollar cosmic sniper shot involves both the target and the projectile moving at least 20 times faster than bullets.
Twelve minutes after the release, a camera-equipped probe began peeling off from the projectile and set on a separate path that will get it as close as 500 kilometres to Tempel 1 shortly after the copper-laden impactor slams into it.
The collision with the gas-spewing rock, which is hurtling through in the solar system at approximately 37 100 km/h, is set for 0552 GMT Monday.
Mission Control will spend most of the upcoming 24 hours guiding the impactor towards its target.
It will likely gouge a large crater on the surface of the comet, sending up a cloud of ice, dust and debris that researchers hope will offer a load of valuable information.
Collision
That is when the fly-by probe will swing into action. It will have approximately 13 minutes to take infrared and other images of the collision and the resulting cloud before it is swallowed by a potential blizzard of particles from the nucleus of the comet.
Comets circling the Sun, which are numbered in billions, are believed to be leftovers from a massive cloud of gas and dust that condensed to form the Sun and planets about 4.6 billion years ago.
Therefore, their geological and chemical structure may contain important clues to the nature of the Universe.
"The comet is definitely full of surprises so far and probably has a few more in store for us," said National Aeronautics and Space Administration project manager Rick Grammier.