That's what Rosetta will fire at poor ol' Churyumov–Gerasimenko in November, any other Duck might be scared. Remember all the technology has been launched Years before the first Smartphone. Mankind has come quite a long way.

On Max-Planck-Institut für extraterrestrische Physik is a very detailed (german) Presentation.

Further Informations from the Manufacturer: Faulhaber

See it in action : Scientists Test Harpoon Used in Rosetta Probe