Mankind's most ambitious and costliest mission to a comet, the enigmatic rocks that some say seeded life on Earth, was heading towards a final countdown at Europe's space base here on Wednesday.
Ten years in the making, with a 10-year trip in front of her and a billion euros (1.25 billion dollars) invested in her, the unmanned craft Rosetta lay atop an Ariane 5 launcher ahead of the 0736 GMT Thursday launch as engineers ticked off a long check list.
"This is going to be the ultimate commentary mission," declared the European Space Agency's director of science, David Southwood. "It will underpin commentary science for the next decade."
The endeavour has been likened to science fiction, for the probe will have to travel five billion kilometre's (three billion miles) to rendezvous with its target, the comet Churyumov-Gerasimenko, 675 million kilometre's (421 million miles) from the Sun.
After firing its thrusters to close on the target, in November 2014 Rosetta will send down a tiny robot lab, Philae, that will gently land on the surface of "C-G" and carry out an ambitious programme to assess the comet's geology as the wander heads around the Sun.
Equipped with 21 instruments to map, sound and probe, Rosetta and Philae hope to find what comets are made of.
The answer, say astrophysicists, could shed light on how life began on Earth.
Comets have always been associated in the human mind with good or ill omens: the birth and death of kings, of failed harvests, floods, wars and earthquakes.
These enigmatic rocks are cursed to encircle the Sun and leave a fiery "tail" in their wake: this reflective glow in the solar rays is caused by the stripping away of their coating of ice and dust as they near the star.
For space scientists, comets are the most primitive material left over from the making of the Solar System some 4.6 billion years ago.
Barely touched by gravity and heat, strangely black in spite of their icy surface, extraordinarily light in density, comets may contain volatile and complex carbon molecules, some experts believe.
These molecules may have been the chemical kick to start life on Earth, according to the so-called "panspermia" theory. It postulates that the Earth, in its infancy, was bombarded with comets and asteroids, whose elements reacted with the oceans to provide the building blocks for DNA.
"This mission has the potential to make spectacular discoveries about the origin of Earth and, perhaps, about the origin of life itself," said Jean-Pierre Bibring, of France's National Centre for Space Studies (CNES).
The plucky pair will need three fly-bys of Earth and one from Mars, using the gravitational pull each time as a slingshot to reach more than 100,000 kph (60,000 mph) to match C-G's speed.
The minutest error in navigation will send the mission hurtling out of the Solar System, for the spacecraft has to meet up with an object just four kilometre's (2.5 miles across).
One of the biggest worries will come after the launch, when the main stage will separate from the upper stage. For the following 105 minutes, the upper stage will coast to a higher altitude before igniting to boost the three-tonne spacecraft to 40,000 kph (25,000 mph), enough to escape the Earth's gravitational pull.
This coasting method has required significant changes to the Ariane 5 upper stage, "a major first," said Jean-Yves Le Gall, director-general of Arianespace, which is carrying out the launch.
Arianespace is fighting to establish the Ariane 5's credibility after the disastrous failure of a 10-tonne version of this rocket on its maiden flight on December 11 2002.
Adding to the tensions is the fact that Thursday's launch is ESA's second stab to get Rosetta into space. A launch a year ago was scrubbed because of reliability fears about the Ariane 5, and that target, Comet Wirtanen, was substituted for "C-G".
Rosetta is named after the stone that explained Egyptian hieroglyphics, thus laying bare the culture of the Pharoahs to modern eyes. Philae is so called after an obelisk that itself provided a key to understanding Rosetta.
Comments
Comments are closed.