Lander 2 was one of four spacecraft attached the Endurance. It was used by the robot CASE to deliver supplies down to Dr. Mann's planet. After Dr. Mann's failed attempt at docking Ranger 1 to the Endurance, Lander 2 was used by Joseph Cooper and Amelia Brand with TARS and CASE to save the Endurance.
Lander 2 was a supply craft that was flown by CASE to deliver colonization equipment from the Endurance to the surface of Mann's planet. When Dr. Mann left Cooper to suffocate on ammonia, Cooper managed to retrieve his transceiver in the snow and radio for help. Brand and CASE used the Lander to rescue him.
With the auto docking sequence disabled, Dr. Mann was unable to achieve perfect docking with Endurance and was killed when opening the airlock hatch. The explosive decompression destroyed Ranger 1, one engine module, and set the Endurance into an uncontrolled spin. Cooper and TARS used Lander 2 to match the spin of the Endurance in order to dock. Cooper used the Lander's main engines to push the Endurance out of Mann's orbit.
Lander 2 was later used by Brand and CASE to reach the surface of Edmunds' planet. With the amount of fuel available after delivering supplies to Mann's planet and pushing the Endurance out of orbit, only two cargo pods could be delivered to the surface of Edmunds. It remains capable of atmospheric flight, but has insufficient fuel to return to orbit. 
- ↑ Interstellar, The Official Novelization