In 2019, the archaeologists uncover their first alien fossil buried beneath Mars' surface and another one was soon found on Phobos. Meanwhile, the UAC's archaeology branch was assigned to study and prove whether there was once life on Mars. government, the United States Marine Corps was assigned to oversee the expedition's activities and to serve as a security branch for the facilities by setting a military outpost on Mars. Perhaps their biggest project was inter-dimensional space travel, the ability to teleport from planet to planet. Those experiments included the construction of energy-based weapons and other forms of technologically advanced warfare. Each facility conducted military experiments deemed classified by the government. In 2018, the UAC installed two science facilities on Phobos and Deimos. In addition, the UAC begins to receive all of their funding from the government. After being given the green light, the UAC advanced their operations in space. In 2013, the company moved on to manufacturing weapons for the United States military via congressional approval.

It began as an organization focusing on archaeology.

The company's headquarters resides in San Diego, California. Before the existence of the Union Aerospace Corporation was the Union Media, Kelliher's first major company, which won him enough wealth to found the UAC. Despite the date of its founding, the UAC's roots go back much further. The Union Aerospace Corporation was founded by Thomas Kelliher on April 3, 1998. Mad Squirrel Mods wants to re-create the UAC into a company that has the same mannerism and mindset as the Weyland-Yutani Corporation in Aliens, as a company that tries to contain and control the threat for their own bio-weapons division. In some versions such as the film adaptation from 2005, the UAC is described as a corrupt company with secrets, and that they are not on the same side as the military. Their technology also seems to differ in each reincarnation. In every reincarnation of DOOM, the UAC would be depicted differently but with similar motives. Every title belonging to the DOOM series has the UAC portrayed as a government-funded corporation responsible for the demonic mayhem that begins on Mars.

Doom shut down the portal secrets