Advanced Extremely High Frequency System

Mission

The Advanced Extremely High Frequency System (AEHF) is a joint service satellite communications system that provides survivable, global, secure, protected, and jam-resistant communications for high-priority military ground, sea and air assets. AEHF enables the Department of Defense to control tactical and strategic forces through all levels of conflict and supports the attainment of space superiority for the joint force. 

Background

The AEHF System is the follow-on to the Milstar system, augmenting the capabilities of Milstar, and expanding the MILSATCOM architecture. AEHF provides connectivity across the spectrum of mission areas, including land, air and naval warfare; special operations; strategic nuclear operations; strategic defense; theater missile defense; and space operations and intelligence. Multiple international partners support the AEHF program.

Features

The AEHF system program of record consists of multiple satellites in geosynchronous earth orbit that provides 10 times the throughput of the 1990s-era satellites with a substantial increase in coverage for users. The first AEHF launched on Aug. 14, 2010, followed by launches on May 4, 2012, Sept. 18, 2013, Oct. 17, 2018, Aug. 8, 2019, and Mar. 26, 2020. AEHF provides continuous 24-hour coverage between north and south poles. The AEHF system is composed of three segments: space (the satellites), ground (mission control and associated communications links) and terminals (the users). The segments will provide communications in a specified set of data rates from 75 bps to approximately 8 Mbps. The space segment consists of the on-orbit satellite systems utilizing crosslink communications to allow for full AEHF and other satellites. The mission control segment controls satellites on orbit, monitors vehicle health and provides communication system planning and monitoring. This segment is highly survivable, with both fixed and mobile control stations. System uplinks and crosslinks will operate in the extremely high frequency range. The terminal segment includes fixed and ground mobile terminals, ship and submarine terminals, and airborne terminals used by all of the Services and international partners. MILSATCOM is responsible for acquisition of the space and ground segments as well as the Air Force terminal segments. Other services will acquire their own terminals.

General Characteristics

Primary Function:
 Worldwide, secure, survivable satellite communications
Payload: Onboard signal processing satellite cross-link
Antennas: 2 Downlink Phased Arrays, 2 Crosslinks, 2 Uplink/Downlink Antennas, 1 Uplink Phased Array, 6 Uplink/Downlink Dish Antenna, 1 Each Uplink/Downlink earth coverage horns

(Current as of July 2020)