The GDSS Philadelphia is an orbital space station and the location of the Global Defense Initiative's central command. Its function is primarily strategic, housing the majority of GDI's senior political and military leadership on a rotating shedule, and GDI bases and command posts worldwide interface with the Philadelphia's central EVA unit. The station can also provide limited tactical support however, as it is capable of deploying drop pods. It is guarded by a highly advanced A-SAT defensive system and the orbital Ion Cannon network.
The Philadelphia was completed prior to the Second Tiberium War and acted as the central command center for GDI forces worldwide. GDI was only able to construct such a complex because of their victory and that they were now the Earth's main government. During the Second Tiberium War General James Solomon coordinated GDI efforts to combat the resurgent Brotherhood, often making use of the station's offensive capabilities to assist his ground commanders. It was also in a transmission to the Philadelphia that Kane announced his return to GDI, where he engaged in a short war of words with Solomon.
During the Firestorm Crisis increased ion particle activity in the upper atmosphere severed links between Earth and orbital assets, including the Philadelphia. GDI global command was assumed by Southern Cross until the conditions passed.
Following the war, there was an effort to move control of the Ion Cannon satellite network onto a space based platform such as the Philadelphia. However, this would have required building another space station at tremendous cost. Instead GDI elected to upgrade the Philadelphia to handle some of the control tasks but kept the rest of it planetside at Goddard Space Center. By the Third Tiberium War the station was in the final stages of its upgrades and ground support was provided by a Chilean spaceport in Blue Zone 8.
In preparation for a new war, General Kilian Qatar planned a strike against the station when it hosted the annual GDI Energy Summit in 2047 to kill GDI's top political and military leaders. After disabling GDI's A-SAT defenses, a nuclear ICBM launched from a secret Egyptian facility struck the station on the fifth day of the summit. The station was destroyed, with 1,047 dead. Significant parts of debris would crash into the Congo Red Zone.
GDI's entire senior command structure was wiped out in the historic attack, essentially beheading the organization and causing its treasury commissioner, Redmond Boyle, to ascend to highest leadership due to GDI's succession protocols. In a series of coordinated global attacks the Brotherhood shortly thereafter overran and occupied the major Blue Zones of the world. The destruction of the Philadelphia thus initiated the Third Tiberium War.
|The following is based on the Nod campaign for Tiberian Sun and some details might contradict canon.|
The Philadelphia has artificial gravity. On videos from the station, people walk around in what seems to be a one-G environment. It also houses a "zero gravity" barrack and launch station to deploy drop pod reinforcement, as seen in the intro of Tiberian Sun.