Space Agency have tested the harpoon that will be used in the lander at the Rosetta probe when it's expected to land on comet 67p by the end of this year after 10 years of travelling. Rosetta carries a space landing device called Phili, ESA plans to deliver the lander to 67p surface in November. The harpoon will be used to fasten the lander to the surface of the comet since the gravity of the comet is only a fraction of that of Earth and its surface is unknown. The manager Stefan Ullermurk said that the challenge is the uncertainty of what to expect of the surface of the comet. Rosetta started its journey from the European Space Board in Kurufer, discovered in 1969 where Rosetta has been circling the Sun on a widening spiral course, swinging past Earth and Mars to pick up speed and adjust its trajectory. Rosetta is due to rendezvous with the comet on August 6th and map it from a height of about 100km in order to find an appropriate landing spot. To convince that the harpoon will do its job perfectly, no matter what the material of the surface turns out to be. The test of the harpoon at the German Space Agency laboratory worked well, they're not perfectly since the harpoon diverted slightly into the wooden box surrounding the experimental material. But Ullermurk was still happy. The firing of the harpoon worked very well, the harpoon penetrated the granulet material and only got stuck in the wooden box.