Advanced Extremely High Frequency System
The Advanced Extremely High Frequency System ( AEHF ) is a joint satellite communication system of the US armed forces for secure, bandwidth-stable, worldwide communications and is used to secure these in times of crisis and war. It is initially intended to complement and ultimately replace the existing Milstar system.
history
AEHF is used for global secure communication with air, land and naval forces and is protected against disruptions. AEHF offers ten times the network capacity and six times the data rate of the Milstar system.
The original order for the AEHF system was awarded to Lockheed Martin Space Systems and Northrop Grumman Space Technology (formerly TRW ) in November 2001 . In this first phase, two satellites and the associated ground control segment will be developed. Project management is carried out by the MILSATCOM Program Office of the Space and Missile Systems Center of the United States Air Force . In 2006 the third satellite was ordered. There are currently three satellites in orbit.
The final AEHF constellation will consist of three or four satellites in radio contact with one another and cover the earth globally between 65 ° north and 65 ° south.
Originally only three AEHF satellites were ordered as the AEHF system was to be replaced by the more advanced TSAT (Transformational Satellite Communications System) which also provides laser communication links. Since the TSAT program was stopped for cost reasons, two more AEHF satellites were ordered. Meanwhile a sixth was added.
Satellites
The satellites, which weigh around 6,500 kg at launch, were built by Lockheed Martin Space Systems on the basis of the commercial A2100 satellite platform. The cost per satellite is approximately $ 580 million. Originally called Milstar-3, the satellites are backwards compatible with the existing Milstar satellites.
The satellites have a signal processing device that enables the EHF / SHF communications to be interconnected . For communication, the AEHF satellites carry a number of antennas that enable hemispherical coverage as well as narrowly defined spot beams. In addition, there are two further antennas for communication with the neighboring Milstar / AEHF satellite, so that communication from any point on earth (with the exception of the polar regions) with any other point is possible via this constellation. The data rates range from 75 bit / s in the safest mode to 8 Mbit / s with less protection. These comparatively low data rates result from the requirement that communication must be maintained even in the event of a crisis under the influence of jammers . Up to 6000 user terminals are supported. The configuration of the spot beams can be changed within a few minutes.
| satellite | Start time ( UTC ) | Starting place | Launcher | NSSDC ID |
|---|---|---|---|---|
| AEHF 1 | 14 August 2010, 11:07 am | CCAFS SLC-41 | Atlas V (531) | 2010-039A |
| AEHF 2 | May 4, 2012, 6:42 pm | CCAFS SLC-41 | Atlas V (531) | 2012-019A |
| AEHF 3 | September 18, 2013, 8:10 am | CCAFS SLC-41 | Atlas V (531) | 2013-050A |
| AEHF 4 | October 17, 2018, 04:15 | CCAFS SLC-41 | Atlas V (551) | 2018-079A |
| AEHF 5 | 8 August 2019, 10:13 | CCAFS SLC-41 | Atlas V (551) | 2019-051A |
| AEHF 6 | March 26, 2020, 8:18 pm | CCAFS SLC-41 | Atlas V (551) | 2020-022B |
swell
- Advanced Extremely High Frequency System (English)
Individual evidence
- ↑ Lockheed Martin Advanced Extremely High Frequency (Advanced EHF) . Archived from the original on October 11, 2007. Retrieved September 12, 2007. (English)
- ↑ US Department of Defense: Defense Budget Recommendation Statement (Arlington, VA)
- ↑ Satellite for secure war-time communications goes up. Spaceflight Now, May 4, 2012, accessed on June 25, 2012 (English).
- ↑ Justin Ray: Rise and shine: Atlas 5 rocket successfully soars at dawn. Spaceflight Now, August 14, 2010, accessed March 12, 2012 .
- ^ Daniel Maurat: Atlas V successfully launched. raumfahrer.net, May 4, 2012, accessed on May 31, 2012 .
- ^ Space Exploration in 2013. In: Russian Space Web. Retrieved June 28, 2019 .
- ^ Air Force's fourth AEHF communications satellite successfully launched from Florida. In: Spaceflight Now. October 17, 2018, accessed June 28, 2019 .
- ^ United Launch Alliance Successfully Launches Communications Satellite for the US Air Force Space and Missile Systems Center. ULA, August 8, 2019, accessed August 8, 2019 .
- ↑ Stephen Clark: Atlas 5 launch caps deployment of ultra-secure military communications network . Spaceflight Now, March 26, 2020