Philae was a success. Especially considering they had no clue what they were landing on when designing Philae (the only info they had were a few bright pixels +

Philae was a success. Especially considering they had no clue what they were landing on when designing Philae (the only info they had were a few bright pixels + limited spectroscopic data). Some experiments couldn't be performed as hoped due to the lander orientation (e.g. the drill, however they could still analyse "atmospheric" dust that the drill transported to the analytical apparatus). But that does not make a mission unsuccessful. What did not succeed was the extended mission due to limited amounts of power. But this was always an optional add-on.