I have watched the movie of Sora no Otoshimono entitled "Sora no Otoshimono Final: Eternal My Master (2014)".
In this movie, when Mikako scans Ikaros' memory, it was revealed that Mikako was an Angeloid who sent Ikaros from the sky. In the anime TV series, it was never shown that Mikako is an Angeloid. She's just a childhood friend of Sugata, whom she calls "Ei-kun", and is the daughter of an influential yakuza boss in Sorami. And there was a possibility that Sugata is also an Angeloid because they were friends since childhood.
So, why did Mikako send Ikaros from the sky? To meet Tomoki?
This is Mikako Satsukitane.