Why "The Reach"?

The term "The Reach" was first coined by Earth's extrastellar authority The Terran Mandate as a project name for their expansion into this sector.
Peleus Theta was a large frontier sector full of independent planets like so many other sectors during the Golden Age of humanity. Back then there was no centralised authority of the sector - Lamela was just a tiny colony founded by a few idealists, already struggling due to their non-reliance on psi-tech.
However, the last couple hundred years before the Scream saw Peleus Theta host one of the Terran Mandate's attempts - from the now lost homeworld of Earth - to regain their authority over a chunk of mankind. If you will: this was Earth's attempt to "Reach" out to one of its more distant subjects.
The system of Jala became the site of a new jump-gate, through which the Terran Mandate stretched their influence to many systems such as Adonie, Aintzane, Xenthra, and beyond. Their expansion, though brutal, was going well. The TM name for Peleus Theta "The Reach" was even adopted informally by many across the sector. Then the Scream hit.
Unlike many of the other Frontier worlds in The Reach, the Terran Mandate made almost exclusive use of psi-tech and psychic minifacturing to assert its dominance - and so when all their psychics suddenly died or went insane their infrastructure collapsed within days. Very few TM leaders survived the Scream and its following Silence, their bones being picked clean by the very frontiersman they had sought to control.
Now, only the Mandate's old halls and tech stand as a reminder of what once unified Peleus Theta under one name. At least the name itself survives, but very few even remember what it means.