Twenty years ago, a space mission to land a probe on a comet was envisioned. And now, ten years and 6 billion kms after, the Rosetta mission have seen success.

It's undoubtedly a resounding accomplishment for European Space Agency (ESA) which launched the Rosetta mission in March 2004. After blasting off from Kourou spaceport of French Guiana, Rosetta and Philae have logged at least 6 billion kms just to reach the comet.

For a time, the spacecraft had gone on standby for almost 3 years. Apparently, it had gone 500 million miles away from the sun that the solar panels can't absorb enough energy to recharge and keep things going. Fortunately, the Rosetta came out of its hibernation just this January and approached its target: comet 67P/Churyumov-Gerasimenko.

The comet, discovered in 1969, orbits the sun at the speed of 135,000 km/h. Measuring 4-km wide, the comet's shape is similar to that of a rubber duck which initially left people doubting if a landing would be possible at all. (This is because if the Philae lander touched down on uneven surface, it could turn over the wrong side -- and has no way to right itself up.)

After its separation from its carrier, Philae started its precarious seven-hour descent onto the comet.

For the controller team, those were 7 hours of nerve-wracking anticipation, especially as a problem arose just at a critical moment. There seemed to be an issue with its thruster which could result in a rough landing at best. Their failure to amend the fault almost resulted in the cancellation of the mission. Eventually, they decided to proceed in spite of it.

Inside the control center of ESA in Darmstadt, Germany, tensions were high.

Finally, around 4pm (GMT), Philae's communications reached Earth: touchdown.

“We are there. We are sitting on the surface. Philae is talking to us. We are on the comet,” said Stephan Ulamec, Philae's lander manager at the control room.

The space mission has already registered a number of firsts; including the first spacecraft to come into close orbit around a comet and of course the first to land a probe. And if things go well, it could also be the first spacecraft to travel with a comet as it circles the sun.

ESA's director general, Jean-Jacques Dordain announced, "We are the first to do this, and that will stay forever."

During another interview with Koyal Info Mag, Dordain noted, "This is a big step for human civilization."

After putting the Philae lander on ground, the Rosetta spacecraft is expected to orbit around the comet and take more images as well as collect various data as it travels toward the sun.

The Rosetta mission will be completed in December 2015, though if there's enough fuel in the spacecraft it might be given a 6-month extension to do even more daring projects. Philae itself has enough juice to continue working until March before its electronics get fried by the sun's heat. However, it might still continue to cling to the comet for around 6 years before losing its grip.

This daring space mission aims to further study the molecular and physical composition of a comet, believed to be made from materials that existed even before the solar system's creation. Koyal Info Mag hopes more will be known of how the solar system formed and how comets are instrumental to the life-sustaining qualities of a planet like Earth.