Propulsion pod

Propulsion Pods are bulbous, about 1/10th the size of a Human Freighter looking somewhat like tugboats used to push supertankers out to sea. They connect the rear of the vehicle with a powerful magnetic coupling and are used to give those Human space vehicles (mainly Freighters) that did not have a Shaw-Fujikawa Slipspace Drive built into them the ability to enter Slipspace.

They are also used during the Escape from Harvest. After the first meeting with the Covenant went sour, Sif, following a plan by Jilan al-Cygni, moved hundreds of these Propulsion Pods from the Tiara out into space, to coordinates weeks and months ahead of Harvest, along its orbital path several days before the Covenant Warship, Rapid Conversion arrived.

When the Covenant began attacking Harvest, those who could fled from surrounding cities to Utgard, the capitol of Harvest and the location of the Space Elevator depot. As war waged around them, +250,000 Humans managed to escape the planet by packing into 236 freight containers which where loaded into the Space Elevator along with two "grease buckets", maintenance containers that carried Johnson's and al-Cygni's militia men. The freight containers that survived, along with the two "grease buckets", then traveled the length of the Space Elevator strands, passing the Tiara and jettisoned out into space, where they coupled with the Propulsion Pods, allowing them to enter Slipspace and escape the Covenant.