First Strike - Cortana 5

Instead of partaking in the slow and inefficient conversation, she analyzed the Covenant pattern of movement in the Epsilon Eridani system and discerned three important things.

First, the Covenant warships had extremely regular elliptical orbits about Reach. There were a total of thirteen heavy cruisers and three carriers moving three hundred kilometers above the surface of the planet. Two exceptions to this patrol pattern were a pair of light cruisers hovering over Menachite Mountain— trapped at the bottom of the gravity well and therefore not an im- mediate threat to her ship.

 Second, there was a blind spot in their patrol patterns that would make a perfect rendezvous location to extract the Chief and the others from their soon-to-be-executed surface mission. She plotted ingress and egress courses, and started the precise calculations she would need if she was to initiate a Slipspace jump so close to Reach.

- Halo: First Strike, Chapter 18