Stratos 4 OVA
After successfully returning to Earth on the renovated Stratos 4, the four main characters are visited by the Comet Blasters Chizuru Kubo and Annette Kerry, who bring them a shocking video. Meanwhile, Orbital Station 7 is in serious trouble...
This two-episode OVA comes between the first and second seasons.
(Source: ANN, edited by Glenn Magus Harvey)