Priority inversion in real-time systems occurs when a higher-priority task is delayed by a lower-priority task due to resource contention. This can lead to system failures or degraded performance. The Mars Rover Pathfinder experienced a priority inversion due to a low-priority task holding a resource required by a higher-priority task, causing indefinite loops. The issue was fixed by enabling priority inheritance in the software. To prevent priority inversion, space mission architectures use priority-based scheduling algorithms and priority inheritance or priority ceiling protocols.