What is the primary goal achieved by propelling a spent upper stage into a graveyard orbit?

Posing minimal collision risk to operational satellites.

A graveyard orbit is a solution specifically designated for spent upper stages that have delivered payloads into high orbits, such as Geostationary Orbit (GEO), where initiating a deorbit burn is prohibitively fuel-intensive. Because these high orbits are crucial operational zones for active satellites, leaving debris there is unacceptable. The command to propel the stage into a graveyard orbit—a higher, stable orbit—is executed to move the large, defunct hardware away from the active traffic lanes. This action minimizes the probability of a dangerous collision with operational assets, effectively isolating the retired hardware from primary mission areas for centuries.