The 6.5 billion kilometre trek from Earth of the European space probe Rosetta, the robot lander Philae riding piggy-back all the way, came to the end of the trail in August. That’s when it met up with Churyumov-Gerasimenko comet.
Now it’s time for Philea to jump. This Wednesday, the European Space Agency will attempt to guide the lander to the surface. Rosetta and Philae have been orbiting till now. The descent is planned to take seven hours, the mini-lab sending back data about gas and dust it goes through. This has never been done.
What’s the difference between a comet and an asteroid? Comets formed far enough from the sun to keep in solid form whatever they’re made of that can melt. You can call it ice, just not necessarily water, although comets do carry water ice.
Asteroids in our system formed closer to the Sun.
Our space producer Jeremy Wilks told us what’s very special about the Rosetta mission: “We believe that comets are actually the things which brought water to Earth. If you look at the water inside me or the water that you drink, it could be that that water came to planet Earth from comets. It is also the case, we think, that some of the complex molecules, some of the aminoacids, may have come to Earth from comets. So if we want to understand the origins of our Solar system, the origins of planet Earth, the origins of our life here as well, we have to understand comets.”
Philae is supposed to work for about five months, till it gets too hot when the comet approaches the Sun in March. The orbiter is supposed to hang in there till August next year. Its controllers will be listening intensely.
Wilks summed up: “The scientific results from the Rosetta mission are going to come out over the next few months and the next few years. Probably for decades to come we are going to be learning from these data, and it really is important because it will help us to understand who we are.”