The Redeemer is a combination dropship-gunship developed by Aegis Dynamics for the United Empire of Earth Navy (UEEN). It is an armored spacecraft used to transport and deploy a squad of soldiers while providing battlefield fire support using its turrets and missiles. The Redeemer has been used in extensive operation against the Vanduul. Surplus models are sold in the civilian market.
Now you can own the Next Great Starship! Designed by Star Citizen’s backers, the Aegis Redeemer is a powerful fighting ship capable of holding its own in combat with a powerful weapons payload. Dotted with turrets and missiles, the Redeemer also doubles as an armored landing craft capable of delivering armored soldiers for first-person combat!
Here is a short history of publications about the Aegis Redeemer from the RSI website, which was a ship that won a contest ran by CIG called The Next Great Starship.
This is an excellent video of the history of the Aegis Dynamics ships from in-game lore, by The AstroPub. Please subscribe to his channel as he produces the most thorough and best Star Citizen lore content.