Galactic Calendar (銀河歴, Ginga-reki^?)

• G.C.790: War breaks out between the Galactic Federation and the ORN Empire.
• Unspecified date: The Fire LEO-01 is sent to destroy ORN's asteroid fortress Dyradeizer. (Thunder Force)
• G.C.820: ORN launches the battle fortress Plealos and destroys Reda. The "Thunder Force II Strategy" operation to destroy Plealos and liberate Nebula is carried out by the Fire LEO-02 "Exceliza". (Thunder Force II)
• G.C.890: The Federation launches the Fire LEO-03 "Styx" in an offensive against the ORN System to destroy the Cerberus defense system and the ORN Emperor Khaos. (Thunder Force III)
• G.C.892: The Federation discovers the existence of the Vios System, where the ORN forces have regrouped and were launching their attacks from. A preemptive offensive is launched to prevent Khaos from being restored. The Fire LEO-04 "Rynex" successfully defeats the Vios forces and destroys the space-cruiser carrying Khaos, but ends severely damaged in the battle. (Thunder Force IV)

Earth Calendar (地球歴, Chikyū-reki^?)

• 2106 A.D.: The space probe Sekika 3 finds the wreckage of Rynex in the Oort Cloud.
• 2108 A.D.: Sekika 3 returns to Earth with Rynex, which is dubbed "Vasteel" by the Earthlings.
• 2139 A.D.: With lots of new scientific breakthroughs resulting from analysis of Vasteel, Earth's scientists create the supercomputer Guardian and build the artificial island of Babel.
• 2145 A.D.: Guardian begins mass-production of starships using Vasteel Technology.
• 2150 A.D.: The Guardian mysteriously achieves sentience and declares war on humanity.
• 2151 A.D.: An elite combat unit is formed to fight the Guardian's forces. Piloting the RVR-01 "Gauntlet", they fight the rogue computer's forces and miraculously emerge victorious. Before being destroyed, Guardian deletes all data pertaining to Vasteel Technology from the Earth's data banks. What little remains of Vasteel Technology is sealed away on Babel. (Thunder Force V)
• 2161 A.D.: Earth is suddenly attacked by an hostile alien force called ORN Faust. Earth's scientists discover that the sealed Vasteel technology was reacting to the alien's approach and also discover about the existence of the Galactic Federation. Reviving the Vasteel technology, they create the RVR-00 "Phoenix" which is then launched to fight the invading ORN forces and to seek asylum with the Federation. After the Federation capital is saved from an ORN attack, the combined forces of the Galactic Federation and Earth's forces launch a counter-offensive against ORN, eliminating the ORN Empire alongside its embryonic leader the ORN Emperor. (Thunder Force VI)

Notes

• G.C. dates are given in the JP manuals of Thunder Force III and IV. The X68000 manual for Thunder Force II states the game to take place 30 years after the beginning of the war. Currently the first title is the only one without a specific date.
• It is currently unknown the time span between the events of the fourth game and the discovery of Rynex's wreckage in 2106 A.D.