From chapter 19:

“Although Project Vela is beginning to show promise for detecting nuclear explosions in space—”

Vela was the name of a group of satellites developed as the Vela Hotel element of Project Vela by the United States to monitor compliance with the 1963 Partial Test Ban Treaty by the Soviet Union. Vela means “[it/he/she] watches over” in Spanish.

—https://en.wikipedia.org/wiki/Vela_(satellite)