Major Tahira Nagi was the flight engineer for mission MME-3233. In an audio recording made before she died, she mentions going numb after being heavily in pain, as well as being proud that whatever group she was a part of accomplished their mission, stating "Humankind has a new planet to call home".
Given that 'MME' likely stands for "Manned Mars Exploraton" as well as her words about humanity having a new planet to call home, Maj. Nagi was most likely in a group of astronauts that were among some of the earliest explorers of Mars prior to colonization in 2050. It is unknown how she was injured, or what her group may have been trying to accomplish, but they were likely the last explorers before colonization, given that she seemed certain that Mars would be suitable for human life.
The insignia on her ID card does not belong to the Ultor Corporation or the Earth Defence Force, implying that the original manned Mars missions were conducted by another group prior to 2050, possibly a government organization or space agency.