An atomic clock ensemble in space is a state-of-the-art technology that provides highly precise and stable time measurements. There are several synonyms for this term, such as space-time standard, space-based timing system, and satellite clock network. These expressions refer to the same concept of using a group of atomic clocks placed in orbit to establish a reliable time reference that can be used for scientific research, communication networks, and global navigation systems. This technology has revolutionized the way we measure time and has become essential for many modern industries and applications. Its high accuracy and stability make it an invaluable asset for research and precision timing.