GAA is the newest science space station and it is to observe and analyze changes in the atmosphere of GOL. The orbiting Orlets1 collects most of the data on GOL and the analyzing happens on the station's science modules. It can transmit them back to GM2 (current home base of the GSA) and be stored there. It still remains to see if it will be of any use after all tho as the atmosphere of GOL seems to be fairly quiet right now.
Station stats: 2.7k units away from HOM / 93 parts / 98 units away from GOL
Here are some images of the station in place.
GOL Atmosphere Analyzer (GAA)
GAA and GOL
GAA and GOL in NaviComp