- You may be looking for the Fallen Angel or short story of the same name.
A fallen angel was the name that the Department used for crashed alien spacecraft in 2050. (TV: Regeneration [+]Shayne Armstrong and S.P. Krause, K9 series 1 (2009).)
The Department recovered parts for the STM from a Korven fallen angel. (TV: Regeneration [+]Shayne Armstrong and S.P. Krause, K9 series 1 (2009)., Angel of the North [+]Bob Baker, K9 series 1 (2010).)
K9 asked if he was considered a fallen angel because his mem drive had crashed. (TV: Regeneration [+]Shayne Armstrong and S.P. Krause, K9 series 1 (2009).)
June Turner asked Drake about a Mede spacecraft that had crashed. Drake had a schematic for it on his computer and was trying to recreate the molecular refractor from the spacecraft. (TV: Alien Avatar [+]Graeme Farmer, K9 series 1 (2010).)
Drake wanted to use fallen angel technologies to control the human population. (TV: Black Hunger [+]Chris Roache, K9 series 1 (2010).)