Command shuttle

"We have survivors to transport to the command shuttle."

- Cortana during the events of Installation 04.

The Command Shuttle was a vessel type in use by the United Nations Space Command. It was likely designed for the purpose of transporting senior officers from ship to land.

Battle of Installation 04
During the opening phases of the Battle of Installation 04, the command shuttle is the lifeboat that brought down all the vital bridge crew from the to the surface of Installation 04.

Speculation
This could be where Captain Jacob Keyes was transmitting his message to MCPO John-117 during the Battle of the Silent Cartographer. He couldn't have been on the Autumn because it had crashed. However, he could have been on a Pelican Dropship, or it may refer to Alpha Base. This theory has been disproved. During the time of the assault on the Cartographer, Keyes was in Alpha Base, overseeing the assault. He also was readying for the attack on the "weapons cache" in the Swamp.

The Command Shuttle may have been an SKT-13 Shuttlecraft, a larger version of the Bumblebee Lifepod, used to transfer the survivors to the Firebase.