ESA Rosetta: Comet Chaser arrives at comet 67/P

After a decade-long journey chasing its target, ESA’s Rosetta has today become the first spacecraft to rendezvous with a comet, opening a new chapter in Solar System exploration.

Comet 67P/Churyumov–Gerasimenko and Rosetta now lie 405 million kilometres from Earth, about half way between the orbits of Jupiter and Mars, rushing towards the inner Solar System at nearly 55 000 kilometres per hour.

The comet is in an elliptical 6.5-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun.

Rosetta will accompany it for over a year as they swing around the Sun and back out towards Jupiter again.

Check on ESA Rosetta status at ESA.int

ESA Rosetta Comet Chaser catches up with comet 67/P today

After an epic, decade-long trek across the solar system, the European Space Agency's Rosetta spacecraft will finally catch up to its target comet early Wednesday (Aug. 6). If all goes according to plan, Rosetta will become the first probe ever to orbit a comet, and you can watch the historic rendezvous live online.

Rosetta is expected to meet up with Comet 67P/Churyumov-Gerasimenko at 4:45 a.m. EDT (0845 GMT) Wednesday, with a crucial 6.5-minute-long engine burn propelling the spacecraft into the comet's orbit.

You can watch a live webcast of all the action at ESA.int beginning at 4 a.m. EDT (0800 GMT), courtesy of the European Space Agency (ESA).

Once Rosetta is in the gravitational grip of the comet, the spacecraft will execute a series of triangular loops around the comet.

Each loop will be about 62 miles (100 kilometers) long and take a few days to complete, mission officials said.



Rosetta blasted off from French Guiana in March 2004. During its 4-billion-mile (6.4-billion-kilometer) chase, the spacecraft zoomed around Earth three times and Mars once for "gravity assists" that helped the spacecraft pick up speed. Rosetta also got up close and personal with two asteroids during its travels.

When Rosetta reached Jupiter's orbit in 2011, ESA engineers put the spacecraft into a deep-space slumber that lasted more than 2.5 years.

Rosetta woke up in January this year for the final phase of its journey to Comet 67P, which is about 2.5 miles (4 km) wide and takes roughly 6.5 years to complete one lap around the sun.

Rosetta has since performed a series of complex maneuvers to slow down and match the comet's pace.

Now, the probe is poised to enter the comet's orbit and travel with it around the sun. Rosetta is also carrying a lander called Philae that's expected to touch down on the comet in November to take samples and study the comet's surface and composition.

ESA Rosetta: Comet chaser nears its target - Comet 67P/Churyumov-Gerasimenko

This artist's impression shows the Rosetta orbiter at comet 67P/Churyumov-Gerasimenko. The image is not to scale. 

Credit: ESA/ATG Medialab

After a decade-long quest spanning six billion kilometres (3.75 billion miles), the European probe Rosetta, will come face to face Wednesday with a comet, one of the Solar System's enigmatic wanderers.

The moment will mark a key phase of the most ambitious project ever undertaken by the European Space Agency (ESA), a 1.3 billion euro ($1.76 billion) bid to get to know these timeless space rovers.

More than 400 million km from where it was launched in March 2004, the spacecraft Rosetta will finally meet up with its prey, Comet 67P/Churyumov-Gerasimenko.

To get there, Rosetta has had to make four flybys of Mars and Earth, using their gravitational force as a slingshot to build up speed, and then entering a 31-month hibernation as light from the distant Sun became too weak for its solar panels.

It was awakened in January.

After braking manoeuvres, the three-tonne craft should on Wednesday be about 100 km from the comet—a navigational feat that, if all goes well, will be followed by glittering scientific rewards.

"It's taken more than 10 years to get here," said Sylvain Lodiot, spacecraft operations manager.

"Now we have to learn how to dock with the comet, and stay with it for the months ahead."

Halley's Comet (1P/Halleys)

Blazing across the sky as they loop around the Sun, comets have long been considered portents of wonderful or terrible events, the birth and death of kings, bountiful harvests or famines, floods or earthquakes.

Astrophysicists, though, see them rather differently.

Comets, they believe, are clusters of the oldest dust and ice in the Solar System, the rubble left from the formation of the planets 4.6 billion years ago.

These so-called dirty snowballs could be the key to understanding how the planets coalesced after the Sun flared into life, say some.

Indeed, one theory, the "pan-spermia" hypothesis, is that comets, by bombarding the fledgling Earth, helped kickstart life here by bringing water and organic molecules.

Until now, though, explorations of comets have been rare and mainly entailed flybys by probes on unrelated missions snatching pictures from thousands of kilometres away.

Exceptions were the US probe Stardust, which brought home dust snatched from a comet's wake, while Europe's Giotto ventured to within 200 km of a comet's surface.

On November 11, the plan is for Rosetta to inch to within a few kilometres of the comet to send down a 100-kilogramme (220-pound) refrigerator-sized robot laboratory, Philae.

ESA Rosetta's Lander, Philae

Anchored to the surface, Philae will carry out experiments in cometary chemistry and texture for up to six months.

After the lander expires, Rosetta will accompany Comet 67P (C-G) as it passes around the Sun and heads out towards the orbit of Jupiter.

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ESA Rosetta: European Satellite Comet Chaser

An artist's view of ESA's Rosetta, the European Space Agency's comet probe with NASA contributions. 

The spacecraft is covered with dark thermal insulation to retain its warmth while venturing into the coldness of the outer solar system, beyond Mars orbit. 

Image Credit: ESA

Comets are among the most beautiful and least understood nomads of the night sky.

To date, half a dozen of these heavenly bodies have been visited by spacecraft in an attempt to unlock their secrets.

All these missions have had one thing in common: the high-speed flyby. Like two ships passing in the night (or one ship and one icy dirtball), they screamed past each other at hyper velocity, providing valuable insight, but fleeting glimpses, into the life of a comet.

Rosetta will do more than this and hopefully, further expand our knowledge of these intriguing objects.

NASA is participating in the European Space Agency's Rosetta mission, whose goal is to observe one such space-bound icy dirt ball from up close, for an extended period i.e. several months.

The spacecraft, festooned with 25 instruments between its lander and orbiter (including three from NASA), is programmed to "wake up" from hibernation on Jan. 20 2014.

After a check-out period, it will monitor comet 67P/Churyumov-Gerasimenko as it makes its nosedive into, and then climb out of, the inner solar system.

Over 16 months, during which time, comet 67P is expected to transform from a small, frozen world into a roiling mass of ice and dust, complete with surface eruptions, mini-earthquakes, basketball-sized, fluffy ice particles and spewing jets of carbon dioxide and cyanide.

Claudia Alexander

"We are going to be in the cometary catbird seat on this one" (??) said Claudia Alexander, project scientist for U.S. Rosetta from NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"To have an extended presence in the neighbourhood of a comet as it goes through so many changes should change our perspective on the nature and timeline of a comet."