Zero Gravity

Zero Gravity is a mission present in Ace Combat 3: Electrosphere, and is the 10th mission in the Neucom Incorporated branch. In this mission, the player is tasked with intercepting a group of General Resource-controlled Orbital Satellite Laser platforms in the Earth's atmosphere. The player is launched onboard the R-352 Sepia prototype shuttle from the Riass Space Center, right before the start of a General Resource siege.

Zero Gravity is particularly notable for being the first and only mission in the Ace Combat series to take place in space.

Mission briefing
(Translation from Project Nemo)

"We have confirmed unidenfitied satellites, and we think that they probably belong to General Resource. Please escape the amosphere aboard a rocket and destroy the satellites in orbit. If these satellites are important to General Resource, retaliation is inevitable. I wish you good luck."

Starting cutscene
Cut to a shot inside a Riass underground launch silo. We can see the R-352 and its rocket booster. The rocket launches. Cut to an external shot of the Comona Islands, as the R-352 rises into the skies. Meanwhile, four fighters can be seen flying around the Riass facility.
 * NEU Commander: General Resource's air defense unit is in the middle of an attack to occupy our base. You'll begin your launch before we come under attack.
 * NEU Commander: [in English] Countdown... 10... 9... 8... 7... 6... 5... 4, engine start! 3... 2... 1... launch!

Cut to a tracking shot of the R-352 in the sky. Fade to black.
 * NEU Commander: Booster separation. [Rocket booster detaches from Sepia; background slowly goes black] Escaping atmosphere. Established orbit.

Gameplay
The four satellites are soon destroyed. The message "Atmospheric Entry" appears on screen. The craft heads towards Earth, pulling its nose up. Afterwards, the R-352 Sepia is pulled towards the earth by the planet's gravitational force. The screen slowly gets a red tint, symbolizing the heat of atmospheric re-entry.
 * NEU Commander: Cruise time is 3 minutes. Please destroy all the satellites.
 * NEU Crewman: [requires translation]

Ending cutscene
Cut to a shot of Earth from the atmosphere. Fade to black. Mission ends.
 * NEU Commander: We have confirmed your successful atmospheric entry on radar.

Mission debriefing
"Thanks to your work, the operation ended safe and sound. With the destruction of laser attack satellites, we have established superiority in offense and defense battles in space."

Trivia

 * If the player runs out of time during the mission, the player will be treated to a special failure cutscene where an OSL satellite kills Nemo with a laser discharge.
 * This is one of the only missions where use of the Orbital Satellite Laser as a special weapon is denied.