Rosetta Comet Chaser Blasts into Space

Rosetta's mission to catch a comet began from the European spaceport in Kourou in French Guiana at 8:17 CET with the launch of the Ariane 5 rocket that carries the three-ton spacecraft.

Minutes after lift-off, the main booster rocket and two solid-fuel rockets separated and fell into the Atlantic Ocean. The rocket reached the Earth's orbit successfully. Then, slightly later than expected, the rocket's upper stage ignited, catapulting the craft out of the Earth's gravitational pull and into space almost two hours after its launch.

"The first step has been taken," Rosetta operations manager Manfred Warhaut said at mission control in Darmstadt, south of Frankfurt, on Tuesday. "That is a very, very good feeling."

Rosetta is now on its way to meet up with the comet Churyumov-Gerasimenko in 2014. The spacecraft's probe, Philae, is scheduled to land on the celestial body in November 2014, the first time anything of the sort will be attempted.

Substitute comet

Last week, Rosetta's launch was delayed twice due to high winds and damage to the rocket's insulation. The €1 billion ($1.25 billion) mission was originally scheduled to begin in January 2003, but then too, technical problems with the rocket caused ESA to scratch the launch, and Rosetta missed the chance to rendezvous with the comet Wirtanen. Churyumov-Gerasimenko, named after the Soviet scientists who discovered it in 1969, was chosen instead.

Little is known about the comet, which ESA describes as a "dirty snowball." But once Rosetta catches up with it, the craft will follow it at speeds of up to 100,000 kilometers (62,000 miles) per hour for a year, while the 100-kilo (220-pound) heavy Philae maps its surface and studies its activities.

Looking for the solar system's origins

Scientists believe comets -- orbiting clusters of frozen gas and dust which date back to the beginning of the solar system -- may contain vital clues as to how the solar system was formed and maybe even how life itself began on Earth. Some astrophysicists contend that comets' complex molecules may have brought the building blocks for life to Earth when they bombarded the planet in its infancy.

The race to discover what makes a comet has been underway for decades:

• 1985 -- NASA's International Cometary Explorer (ICE) traverses the tail of Comet Giacobini-Zinner.
• 1986 -- A small armada of space craft follow Halley's Comet: the Soviet Union's Vega 1 and 2, NASA's ICE, and Japan's probes Suisei and Sakigake. On March 13 and 14, ESA's Giotto comes the closest to the comet with 596 kilometers. It relayed images of the potato-shaped nucleus back to Earth and data showing that comets contain carbon dioxide, hydrogen and oxygen -- the building blocks of life.
• 1992 -- Continuing its flight through the solar system, Giotto passes the comet Grigg-Skjellerup within 200 kilometers. ESA technicians reactivate the probe and redirect its antenna.
• 2001 -- NASA's Deep Space 1 probe comes within 2,200 kms of Comet Borrelly. It takes black-and-white infrared photos and collects data about the comet's gases and magnetic field.
• 2002 -- NASA's Comet Nucleus Tour (Contour) is lost after it began a post-launch burn to leave Earth's orbit. It should have researched two comets.
• 2003 -- Rosetta's original launch date to land on the comet Wirtanen is cancelled due to problems with the Ariane rocket.
• 2004 -- NASA's spacecraft Stardust makes the closest-ever approach to a comet, coming within 250 kms of Wild 2 after collecting dust samples from its "coma," the halo-like glow surrounding the comet's head. The samples are due to return in a parachuted capsule on Jan. 15, 2006.
• On Dec. 30, 2004 NASA is scheduled to launch Deep Impact to meet up with Comet P/Tempel 1 in July 2005. It will fire a 350-kilo copper slug at its nucleus and use a spectrometer to analyze the elements of the gases and material that are ejected.