The harpoons were designed to anchor into a Dirty Snowball, as the comet was "known" to be accor4ding to the Orthodox model of solar- system formation. Since that model is pure fantasy, Philae's harpoons could not anchor into the rocky surface of the asteroid fragment that thjis comet. like all the otherds, actually is.
Shane Mage
This cosmos did none of gods or men make, but it always was and is and shall be: an everlasting fire, kindling in measures and going out in measures.
Herakleitos of Ephesos