View source for Engineering:UFO (satellite)

{{nofootnotes|date=January 2018}}
{{out of date|date=January 2018}}

{{Infobox spacecraft class
|image=UFO satellite.jpg
|caption=Artist's impression of an UFO satellite
|name = Ultra High Frequency Follow On
|country = {{wipe|United States}}
|bus = HS-601
|applications = Military communications
|orbits = [[Astronomy:Geosynchronous orbit|Geosynchronous]]
|operator = {{wipe|United States Air Force}}
|lifetime = 14 years
|status = Active
|orders = 0
|built = 0
|launched = 11
|operational = 
|retired = 
|failed = 
|lost = 1
|first = 
|last = 
|mass =  
}}

The '''Ultra High Frequency Follow-On''' ('''UFO''') system is a United States Department of Defense (DOD) program sponsored and operated by the U.S. Navy to provide communications for airborne, ship, submarine and ground forces. The UFO constellation replaced the U.S. DOD Fleet Satellite Communications System (FLTSATCOM) constellation and will consist of eleven satellites. The ground terminal segment consists of equipment and resident personnel at existing satellite communication stations.  The spacecraft are controlled by the Naval Satellite Operations Center (NAVSOC) located at the Naval Base Ventura County, Point Mugu, CA.

==UHF Follow-On satellites==
The [[Physics:Ultra high frequency|UHF]] satellites will primarily serve tactical users. UFO provides almost twice as many channels as FLTSATCOM and has about 10 percent more power per channel. The [[Physics:Extremely high frequency|EHF]] package on satellites four through eleven have an Earth coverage beam and a steerable five-degree spot beam that enhances its tactical use. The EHF capability also allows the UFO network to connect to the strategic [[Engineering:Milstar|Milstar]] system.  Satellites eight, nine and ten also carry the Global Broadcast Service antennas that operate in the Ka-band.

First launch of the UFO took place on 25 March 1993, with constellation completion dependent on replacement needs for the aging FLTSATCOM constellation. The [[Engineering:Atlas II|Atlas II]] is the current launch vehicle of choice; however, space shuttle compatibility existed. The UFO bus and payload weigh 2,300 pounds (1.04 [[Tonne|tonne]]). The solar array spans 60.5 feet (18.4&nbsp;m) and produce 2,500 watts at the end of the planned 14-year lifetime.

The UHF system supports stationary and mobile users including manportable, ships, submarines, aircraft and other mobile terminals. The UFO Follow-on system is schedule for replacement by the Mobile User Objective System (MUOS).

==References==
{{reflist}}
*Federation of American Scientists: [http://www.fas.org/spp/military/program/com/ufo.htm UFO System]
*Boeing: [https://web.archive.org/web/20070228081235/http://www.boeing.com/defense-space/space/bss/factsheets/601/uhf_followon/uhf_followon.html UFO System]
*GlobalSecurity.org: [http://www.globalsecurity.org/space/library/report/1999/nssrm/initiatives/ufo.htm UFO System]
*GlobalSecurity.org: [http://www.globalsecurity.org/space/systems/muos.htm MUOS]

[[Category:Military communications]]


{{Sourceattribution|UFO (satellite)|1}}