Timeline

The timeline in DOOM: Reawakened follows a story that does not include any events from Final DOOM and DOOM 64. Elements from id Software's official timeline to The Ultimate DOOM and DOOM II: Hell on Earth began as unclear and unexplained but are being expanded in this new timeline by Mad Squirrel Mods.

Concept and Creation
In regards to the events of the original games, id Software did not have any explanation for certain elements such as when the Union Aerospace Corporation was founded and who founded it. Mad Squirrel Mods is expanding on these elements as means of renewing the original DOOM lore. The Doom Wiki does suggest that the original games take place in a now alternate history. For example, there is the concept of building advanced-tech science facilities on Mars' moons in the year 2018.undefined In the real-life 2018, no such thing has happened and may not happen. DOOM: Reawakened will have its own timeline with only The Ultimate DOOM and DOOM II: Hell on Earth being part of the canon.

Pre-1990s

 * Before 1998 - Thomas Kelliher creates the Union Media.

1990s

 * April 3, 1998 - The Union Aerospace Corporation (UAC) is founded.
 * May 11, 1998 - The UAC begin their first archaeological expedition.

2010s

 * July 7, 2013 - The UAC receives congressional approval to expand their company into making weapons for the United States military. They permit the military to oversee all of their operations.
 * February 27, 2017 - The UAC begin working on space travel.
 * November 2, 2017 - The Mars expedition is approved.
 * March 15, 2018 - The top secret science facilities on Phobos and Deimos have been built.
 * March 16, 2018 - The United States Marine Corps establish a base on Mars to serve as security and military advisers for all top secret projects.
 * March 18, 2018 - The Mars expedition facilities are operational.
 * April 4, 2019 - Doomguy assaults his superior officer. As punishment, he is assigned to the military outpost on Mars. A few days or so after his trial, his son is born.

2020s

 * October 21, 2020 - UAC archaeologists uncover the first Martian Hell Portal but do not report it to the authorities.
 * December 8, 2020 - The UAC scientists of the inter-dimensional space travel project begin to experiment with the technology of the Hell Portal.
 * August 6, 2021 - After the inter-dimensional space travel project sees multiple failures, the UAC attempts to merge the Martian technology into their own.
 * January 22, 2022 - The expedition mysteriously loses contact with the Deimos Facility.
 * February 5, 2022 - The first attempt in testing inter-dimensional space travel (secretly with the technology of the Hell Portal) brings disastrous results. The gateway to Hell is opened, and the Phobos Facility sends a distress call to the marines on Mars. A squad of marines go to Phobos to investigate the problem. Many of them die, leaving Doomguy as the only surviving member of the team. He battles his way throughout the Phobos Facility.
 * February 6, 2022 - Doomguy finds himself in the Deimos Facility. Fighting and surviving, he encounters and defeats a Cyberdemon. He then ends up in Hell kills many demons while trying to find a way to escape.
 * February 7, 2022 - Doomguy returns to Earth, witnessing the demonic invasion that is later signified as the First Demonic War and returning home to find his family dead.
 * February 9, 2022 - The military discovers the existence of a Hell Portal in the middle of Doomguy's hometown.
 * February 10, 2022 - The UAC defy the military by sending security patrols assigned to retrieve the second Hell Portal. The security patrols fail and are turned into zombies.
 * February 13, 2022 - Doomguy returns to Hell, destroys the Icon of Sin, and puts a stop to the war.
 * February 22, 2022 - After being treated of his injuries, Doomguy is given a hero's welcome.
 * June 18, 2022 - The truth about the first Hell Portal being used for the UAC's teleportation experiments is revealed.
 * September 27, 2022 - After charges have been filed in court, Thomas Kelliher is forced to step down as head of the UAC.
 * November 11, 2022 - Doomguy retires from the USMC.
 * January 12, 2023 - Ian Kelliher becomes the new head of the UAC.
 * September 3, 2025 - The Hero's Monument (or the Doomguy Monument) has been built.
 * March 19, 2026 - The UAC return to manufacturing weapons but with the military constantly spying on them.
 * August 24, 2028 - All of Earth's nations form a prosperous alliance.

2040s

 * March 31, 2044 - Jeremiah Bellwhether becomes the new head of the UAC.
 * April 12, 2044 - Bellwhether recovers a backup copy of the Mars expedition's research on the first Hell Portal.
 * November 16, 2044 - The UAC creates their first successful teleporters in secret and implements them to the design specs of the Milano.
 * February 11, 2045 - The UAC launches the science vessel Milano in search for the third Hell Portal.

2050s

 * May 6, 2051 - Bellwhether dies of natural causes.
 * May 13, 2051 - Silas Hildern becomes the new head of the UAC.
 * April 7, 2052 - The Milano returns to Earth with the third Hell Portal and with all crew members deceased.
 * April 10, 2052 - Old Doomguy is pulled from retirement.
 * April 11, 2052 - The events of DOOM: Reawakened begin.

Trivia

 * Some events of Mad Squirrel Mods' DOOM timeline respectfully match events of id Software's timeline for the original games but with a few modifications.
 * In id Software's timeline for the original games, there is no mention of Martian technology being implemented into the UAC's teleportation experiments. Mad Squirrel Mods felt that having the teleportation technology being 100% human instead of part alien would have too many similarities with the sci-fi horror film Event Horizon and wanted to give it a somewhat more realistic approach.