- "Attention all aircraft. This rocket launch is critical. Maintain air superiority until launch is complete."
- ― Comona Base
Operation Countdown, also known as the Battle of Comona Islands, was one of the largest aerial battles since the Belkan War nine years earlier. The engagement centered on the ISAF's attempt to launch a reconnaissance satellite in preparation for its landing operations on the Usean mainland.
The presence of Stonehenge made deployment of recon aircraft over the mainland impossible, so the success of the satellite's launch was crucial to the success of the ISAF's war-effort. The Eruseans understood this just as well as ISAF did, and the Federal Erusea Air Force responded by deploying a large number of its air-superiority fighters to prevent the launch. Anticipating this response and having only one window of opportunity to launch the rocket, ISAF called upon its own air forces to defend the skies above the rocket and ensure a successful launch.
Among the Erusean air forces over the islands was the infamous 156th Tactical Fighter Wing ("Yellow Squadron"), which had been sent to intercept and destroy the satellite before it could launch. By the time ISAF was able to send its remaining air units to reinforce the ISAF pilots already in the combat area, a massive dogfight was already underway. Yellow Squadron effortlessly picked off ISAF pilots one-by-one, and the skies above the facility became tangled with the missiles, bullets, smoke and contrails of countless aircraft. During the engagement, Mobius 1, an ISAF pilot, engaged and damaged a Yellow Squadron fighter. Yellow Squadron withdrew from the airspace and retreated northwest, returning to the mainland and leaving their mission's success in the hands of the remaining Erusean fighters.
Shortly after the retreat of the Yellow Squadron, the tide of the battle turned in ISAF's favor. The pilots, no longer under the threat of the Yellows, were now able to down the Erusean pilots quickly. Suddenly, AWACS SkyEye detected a squadron of B-2 bombers on radar approaching the base from the west. Mobius 1 proceeded west and intercepted the bombers while his allies remained tangled in the furball over the launchpad.
- "Rocket has reached 40,000 feet. It is now immune to enemy action."
- ― Comona Base
By the time the rocket entered its final countdown sequence, the skies were almost completely sanitized of Erusean fighters. The rocket launch was successful, and the satellite was soon on its way into the upper atmosphere. With the ability to perform recon from space, ISAF could now concentrate efforts on its invasion of the Usean mainland.
- The operation area resembles Florida: the bridges and air base resemble Key West, whereas the launch facility resembles Cape Canaveral.
- The rocket being launched resembles the European Ariane 5.
- Operation Battle-Axe was thought to be the largest air-to-air battle in history until Operation Countdown. The title was later taken by the dogfight during the Invasion of Gracemeria.
- There are three unmarked friendly C-5 Galaxys in this mission; they are parked alongside a runway on one of the larger islands to the east of the main operation area.