Which of the following frequency ranges is used for AES to space up-links?

The frequency range of 1626.5 - 1660.5 MHz is designated for Aeronautical Emergency Services (AES) and is commonly utilized for space up-links. This band is specifically allocated for satellite services and enables communication between aircraft and satellite systems, facilitating essential data transmissions such as emergency messages or other critical communications.

This frequency range is part of the broader S-band spectrum used for various satellite communications, providing reliable connectivity for aircraft-to-satellite links. The choice of frequency is vital as it ensures optimal performance, including better signal propagation and resilience against atmospheric interference.

In contrast, other frequency ranges mentioned do not align with the specific uses for AES space up-links:

• The frequency range of 1525.0 - 1559.0 MHz is used for other aeronautical mobile-satellite services, but it is not specifically designated for AES communications to space.

• The ranges of 4 GHz - 6 GHz and 10 GHz - 12 GHz are typically utilized for different applications, such as terrestrial microwave links and other satellite communications, but they do not pertain to the operational frequencies for AES space up-links.

Thus, the correct choice reflects the distinct allocation for aeronautical emergency communications within the satellite spectrum.