Challenges: High-throughput satellite communications require ground stations and star clusters to maintain ns-level time alignment, and satellite nodes need to be switched quickly.

Challenges: Industrial Internet of Things requires microsecond-level multi-device collaboration and resistance to electromagnetic interference in the workshop.

Challenges: Deep-sea/polar equipment needs to withstand long-term autonomous timing capabilities in high-pressure and ultra-low temperature environments.

Challenges: High-frequency transactions require nanosecond timestamps, and globally distributed data centers require clock drift <100ns.

Challenges: Quantum bit manipulation requires femtosecond laser synchronization, and long-term stability of 10^-18 is required.