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MILSTAR Block I satellite. USAF Illustration
SMC emblem

Milstar (originally an acronym for Military Strategic and Tactical Relay [satellite], but now a name with no inherent meaning) is a United States government satellite communications system that provides secure, jam resistant, worldwide communications to meet wartime requirements for United States military users.

Overview

The Milstar program was a joint service program conceptually started in 1978 to develop and acquire extremely high frequency (EHF) satellites; a satellite mission control segment; and new or modified Army, Navy and Air Force communications terminals for survivable, jam-resistant, worldwide, secure communications to strategic (global nuclear conflict) and tactical (conventional theatre conflict) warfighters. The Military Satellite Communications (MILSATCOM) division of Air Force Space Command's Space and Missile Systems Center at Los Angeles AFB, California, is responsible for development and acquisition of the Milstar space and mission control segments. The development and production program evolved into two block buys. Milstar (block) I was from industry contract award in 1982 [1] through 1995 and delivered two satellites. Milstar (block) II was from industry contract award in 1992 through the last launch in 2003 and support operations through 2005.

Milstar I satellites 1 and 2 have a low data rate (LDR) payload that supports strategic and tactical forces with emphasis on highly survivable, minimum essential communications. Milstar II satellites 3 through 6 have both LDR and medium data rate (MDR) payloads with increased tactical capabilities, including higher data rates to mobile forces and nulling that will neutralize close-in enemy jammers. Satellite 3 did not reach its proper orbit and the satellite was placed in a non-interference orbit and shutdown. Satellites 4 and 5 were successfully launched and placed into operation. The Milstar program was officially completed in FY05. [2] The operational Milstar satellite constellation consists of these five satellites positioned around the Earth in geosynchronous orbits. Each satellite weighs approximately 10,000 lb (4,536 kg) and has a design life of 10 years.

Milstar Satellite Payloads

Each Milstar satellite serves as a smart "switchboard" in space by directing traffic from terminal to terminal anywhere on the Earth. The satellite establishes, maintains, reconfigures and disassembles required communications circuits as directed by the users.

LDR Payload

The Low Data Rate (LDR) payload offers 192 user channels and relays coded teletype and voice messages at data rates of 75 to 2400 bits per second. The waveform is a modified version of MIL-STD-1582C and is designed for Low Probability of intercept, operation in nuclear environments, and is heavily signal processed.[3][4] The LDR payload was part of Block I and Block II.

  • EHF Receive, 43.5 to 45.5 GHz
  • Signal Processing and Routing
  • SHF Transmit, 20.2 to 21.2 GHz, 25 watts
  • Time and Frequency Reference
  • Dehop and Hopping synthesizers

System supports string or ring satellite to satellite communications. Crosslink operational frequencies are chosen to be at or near Oxygen (O2) transition frequencies. [5] Thus the oxygen in the Earth's atmosphere atmosphere absorbs the signal, preventing detection by Earth-based ground stations.

Crosslink (60 Ghz) on two frequencies for Block I, four frequencies for Block II. Each Satellite has two Crosslink antennas.[6]

UHF Payload

The UHF subsystem utilizes receive and transmit helix antennas providing full earth view coverage. The UHF signals route to the spacecraft processors allowing crossbanding between UHF and EHF/SHF users.[7][8]

  • AFSATCOM AFSATII-R channels frequency hopped; 75 bps[9]
  • One Fleet Broadcast transmitter BPSK 1200 bps channel[10]
  • UHF Transmit 243.7 to 244.5 Mhz
  • UHF Receive 335.6 to 339.6 MHz

MDR Payload

The Medium Data Rate (MDR) payload offers 32 user channels and relays coded teletype,facsimile, and voice messages at data rates of 4800 to 1,540,000 bits per second. The waveform is a modified version of MIL-STD-188-136 and is designed for Low Probability of intercept, operation in nuclear environments, and is heavily signal processed.[11][12] The MDR payload was only on Block II.

  • EHF Receive, 43.5 to 45.5 GHz
  • Signal Processing and Routing
  • SHF Transmit, 20.2 to 21.2 GHz, 60 watts
  • Time and Frequency Reference
  • Dehop and Hopping synthesizers
  • Two Nulling receive antennas

Bus/Satellite Characteristics

  • Power plant: Solar panels generating 8 kW
  • Weight: ~10,000 lb (4,500 kg)
  • Orbit altitude: 22,250 nautical miles (41,200 km) geosynchronous
  • Launch vehicle: Titan IVB/Centaur upper stage
  • Unit Cost: $800 million, then-year dollars

Historical

In November 1978 the Military Satellite Communications Systems Office published an architectural document titled "Framework for MILSATCOM Development." The document set forth three functional classes of military satellite users: (1) wideband, (2) tactical/mobile, and (3) nuclear-capable systems.[13] Today class (3) is known as Protected Communications Systems. Milstar was designed for the nuclear-capable and tactical users; users requiring assured protected communications. Assured means: (1) operation in a nuclear environment that contains EMP, scintillation,and nuclear radiation effects, (2) Operation through jamming. Protected means: Low probability of intercept LPI) and Low Probability of Detection (LPD) for covert missions.

Early Strategic Satellite Systems

Communications with Nuclear-capable weapons systems were initially performed by the US Air Force Satellite Communications (AFSATCOM) system, first launched April 1978, and operational on May 19, 1979. [14] The system provided a global capability for dissemination of Emergency Action Messages (EAMs) to the nuclear-capable forces, and associated report-back communications. Initial users of the AFSATCOM system were small ground-transportable and airborne terminals. The AFSATCOM system was a Ultra-High Frequency (UHF) communications package hosted on five separate satellite systems through the 1980's and even into the 1990's: LEASAT, FLTSAT, satellite data system, DSCS III, and a classified host satellite.[15] It was designed to direct the Single Integrated Operations Plan (SIOP) forces, composed of U.S. Air Force bombers, ICBMs, ALCMs, and the U.S. Navy SLBMs, and would be used in theater strike operations, including an array of U.S. Army weapon systems and the U.S. Air Force GLCMs. There were a number of package configurations, but the basic one consists of 12 frequency hopped narrowband (5 KHz) channels. Data rate is teletype 75 bits per second (bps).[16] A single channel transponder (SCT) is hosted on DSCS III providing for EAM dissemination to the strategic nuclear forces and to the missile launch complexes in the continental United States (CONUS), and it supports the Commander-in-Chief (CINC) EAM dissemination to the special ammunition storage (SAS) sites worldwide.[17] The UHF Payload on the Milstar satellite continues the traditional AFSATCOM mission.

Experimental Strategic Communications Systems

Early on it was recognized that UHF systems had limitations. Although they were easy to setup, their beamwidth (footprint on the Earth) was wide, and their bandwith was low. The US Air Force and US Navy were both looking at the EHF and/or SHF band to solve these problems. At EHF the antenna sizes can become smaller, a particularly attractive feature for the Navy in improving their strategic submarine communications. Smaller beamdwidths also meant that there is less change of a nearby enemy intercepting communications. Wider bandwidths meant that the signal could employ frequency hopping (spread spectrum) to improve anti-jamming[18].

Flight Model, Lincoln Experimental Satellite (LES) 8/9 USAF Photo

The US Navy and US Air Force wanted to try out these concepts. In the early 1970's they contracted MIT Lincoln Laboratory to build a pair of experimental communications satellites, LES-8 and -9, to demonstrate the technology necessary to deploy an EHF satellite communication system for command and control of the SIOP forces. The satellites were designed to operate in a 23 degree inclined circular geosynchronous orbit (non-standard). They were to communicate with fixed and mobile terminals. Uplinks, downlinks, and intersatellite links used the EHF band augmented with standard UHF band links. LES-8 and -9 were launched together on 14 March 1978 aboard a Titan IIIC booster. Signal processing included spread-spectrum modulation and demodulation techniques for improving anti-jam communications links. The use of an intersatellite link was a first and successfully demonstrated, although not at the desired goal of 60 Ghz. LES 8/9 provided a proving of the basic technologies needed for MILSATCOM protected missions such as Milstar.[19]. Many experiments were conducted on these satellites, including the highly successful demonstration of periscope antenna operation from the USS Finback with the satellites, part of Navy operation CLARINET OMEN. LES Payload:[20] The Navy EHF SATCOM Program (NESP) evolved from the CLARINET OMEN 8/9 experiment.[21]

LES Payload:[22]

  • UHF Transmit: 240-400 MHz, 32 watts
  • UHF Receive: 240-400 MHz
  • EHF Transmit: 36/38 GHz ; Fixed Frequency; 0.5 watts
  • EHF Receive: 36/38 GHz ; Fixed or Hopping
  • EHF Crosslinkk: 37 GHz ; Fixed Frequency; Autotrack system
  • Data Rates: 10 or 100kbps
  • Signal Processing: Interleaving / Coding

STRATSAT Study

From 1979 through 1981 the Air Force proposed a new strategic satellite system called STRATSAT to replace the AFSATCOM mission. It was to be a four-satellite constellation, utilizing the technologies demonstrated on LES, designed solely to support nuclear forces. It would avoid potential anti-satellite and nuclear threats by orbiting in a supersynchronous orbit of 110,000 miles. It would operate in the EHF range to provide more bandwidth for anti-jam waveforms. Congress rejected Air Force requests for a STRATSAT program for three consecutive years.[23]Congress viewed the mission for strategic only as too narrow for the cost. A new system, combining strategic and tactical systems emerged in 1981 known as MILSTAR.[24]

Milstar and FEP

Looking beyond the LES 8/9 project, the US Navy continued discussions with MIT Lincoln Laboratory to develop a full scale EHF system design that would provide jam resistant communications to their ships and subs. The Navy formally added this system to their DoD budget. However the Air Force objected, stating that EHF-satellite communications should be exclusive to the Air Force since they had the largest projection of future users. The Secretary of Defense sided with the Air Force, giving them the lead of a joint program office.[25] The Air Force and MIT was given the go ahead in 1974 for the Fleet(satcom) EHF Program (FEP) packages.[26]. were carried aboard the FLTSATCOM (FSC) satellites F7 and F8, launched in 1986 and 1989 respectively.



This successful effort resulted in authorization by Congress and DOD for the Navy to put FEP on FLTSAT's 8 and 9 and UFO's 1 through 4.[27]

MILSTAR Startup

On October, 1, 1981, President Reagan signed National Security Decision Directive 12[28]. the strategic modernization program. The directive called for development of a command and communications system for strategic forces that is able to survive and endure before, during, and after a nuclear attack. This directive, among other things, established the MILSTAR mission and program. The Air Force officially initiated the MILSTAR program in November 1981. Satellite bus and integration validation contracts were awarded In February 1982 to Lockheed, TRW and Ford Aerospace. In July 1982 Ford withdrew from the competition. Contracts for the electronics payload validation were awarded in May 1982 to a Hughes/TRW team, General Electric, and Ford Aerospace. Ford and General Electric subsequently withdrew from the competition.[29] A request for proposal for full-scale engineering development was issued on September 15, 1982. On February 25, 1983, at the end of the concept validation phase, Lockheed was selected by the Air Force for the MILSTAR full-scale engineering development and initial production phase. Hughes/TRW became subcontractors to Lockheed for the electronics payload.[30]


Space Segment

Cold War Years

At the end of the concept validation phase the Milstar system was to include a constellation of eight satellites. Three in geosynchronous orbit. Four in circular polar orbits. One spare. Inter-satellite laser crosslinks were part of the plan. Each satellite would be able to communicate with three neighboring satellites over the laser crosslinks. A highly classified payload was also included in addition to the Crosslink and LDR payload. The projected launch date for the first satellite was 1987. [31] [32]

System studies continued with further changes to the system architecture. The polar missions were eliminated and the Crosslink system was changed from lasers to 60GHz RF.[33]

One year later in 1984, the DoD slipped the launch date (amount unknown) to allow full resolution of new technology risk reduction. Schedule slips and cost overruns continued in 1984 through 1986, prompting Congress to call for an independent cost analysis of the program in 1985. However during this time Milstar had full support and funding from Congress. Starting in 1987 though Congress started to reduce the DoD requested budget for Milstar. This was in part due to Gramm-Rudman acts of 1985 and 1987, but also concerns over system interoperability between the satellite and ground segments and schedule slippage reduced committee support.[34]

Post Cold War

Programmatic problems, coupled with the end of the Cold War and the reduction (but not elimination) of emphasis on nuclear survivability, interest in sustaining Milstar as a program diminished. For the budget year 1990, after continued schedule slippage and cost overruns by the program, the House Appropriations Committee severely cut the Milstar budget and asked for program termination after the launch of the third satellite. The full Congress did not require termination, but did request the deletion of the classified payload, slipped the schedule another year, and greatly reduced the ground terminal work.[35]


In January 1991, DOD reported to the congressional defense committees its plans to restructure the Milstar program rather than develop an alternative advanced system. Key changes associated with lowering Milstar costs included reducing (1) the constellation size from 8 to 6 satellites, (2) the number of ground-based constellation control stations from 25 to 9, and (3) the total terminal quantity from 1,721 to 1,467, particularly the most costly and complex terminals. Also, several survivability features on satellites and ground equipment are to be eliminated. A medium- data rate capability to satellite 4 and beyond to provide greater utility to tactical forces. [36]


In the early 1990s, the Air Force attempted to cancel the program but both the Army and Navy resisted this effort, for the following principal reasons: The Army had made a significant investment in Milstar ground terminals, particularly to support large "trunking" systems needed at the Corps and Echelon-Above-Corp level.The Navy had been forced to forgo all other Arctic satellite communications capabilities because of the Milstar high-elliptical component and had no other option for communicating with forces at northern latitudes[37]



In 1991 the program was restructured in response to congressional directions. From 8 to 6 satellites. Ground based control stations from 25 to 9. Changes in the user terminal complements. (ref 3).


Tactical and mobile users were serviced by FLTSAT, TACSAT

program received "Highest National Priority" status in 1983

Ground Segment

The Electronic Systems Center at Hanscom AFB, Massachusetts, is responsible for the Air Force portion of the terminal segment development and acquisition. The 4th Space Operations Squadron at Schriever AFB, Colorado,and the 148th Space Operations Squadron at Vandenberg AFB, California; are the front line organizations providing real-time satellite platform control and communications payload management.

Airborne and Ground Command Post Terminals

The Milstar Airborne and Ground Command Post Terminals are designed to be rugged, reliable and to survive extreme environments, including modern conventional and nuclear warfare. They provide secure, jam resistant, voice, data and teletype communications to both tactical and strategic commanders. They are also backwards compatible with existing upgraded AFSATCOM Terminals, in order to make full use of existing assets.

In May 1989, the Defense Acquisition Board approved low rate initial production (LRIP) of 43 Command Post terminals. In May 1993, a production contract was awarded for another 44 terminals, bringing the total production quantity to 87. Two prime contractors are producing these terminals, Rockwell International Corporations and Raytheon Company. To date, all LRIP terminals have been delivered and 15 have been installed and are ready for EHF operations. The remaining delivered terminals are currently undergoing installation. Additionally, there are approximately 15 Engineering Development Model (EDM) terminals currently in use by the Milstar community.

The terminals are to be used in several different configurations: 

   * E-4B National Airborne Operations Center
   * E-6B ABNCP/TACAMO
   * Fixed Ground sites
   * Transportable Ground sites

These terminals are fully compatible with the EHF and UHF frequency bands currently used by Milstar, with a SHF band capability in development.

Installation and checkout testing has been performed on multiple airborne and ground terminals. All tests have been fully successful, proving the viability of the technology and interoperability between the Milstar system and other military communication systems. These successes have allowed the program to continue into the current production contracts, which are proceeding on schedule and under cost.

User Terminals

Launch History

  • Milstar 1 launched 1994-02-07 1994-009A USA-99
  • Milstar 2 launched 1995-11-06 1995-060A USA-115
  • Milstar 3 launched 1999-04-30 1999-023A USA-143, Launch system error inserted spacecraft into a useless orbit
  • Milstar 4 launched 2001-02-27 2001-009A USA-157
  • Milstar 5 launched 2002-01-16 2002-001A USA-164
  • Milstar 6 launched 2003-04-08 2003-012A USA-169

Other MILSATCOM systems include (organized by product line):

Protected Comm Wideband Comm Network Comm
Milstar Defense Satellite Communications System (DSCS) Transformational Satellite Communications System (TSAT) -- a future system (also continuing the protected and wideband lines)
Advanced Extremely High Frequency satellite (AEHF) -- a near-future system Wideband GlobalSat Comm System (WGS) -- a near-future system

Notes

  1. ^ GAO (July 31, 1986). "Case Study of the MILSTAR Satellite Communications System". GAO. NSIAD-86-45S-15. {{cite journal}}: Cite journal requires |journal= (help); line feed character in |title= at position 19 (help)
  2. ^ US DOD (2006-02-24). "0604479F MILSTAR LDR/MDR Sat Comm" (PDF). Defense Technology Information Center. Retrieved 2007-08-21.
  3. ^ Donald H. Martin (2000). Communication Satellites. AIAA. ISBN 1884989063.
  4. ^ James H. Hoffman (1994). "Milstar Terminal lnteroperability". AIAA. AIAA-1994-1016-517. {{cite journal}}: Cite journal requires |journal= (help)
  5. ^ Bruce Gary (2007-06-22). "Atmospheric emission sources". Bruce Gary. Retrieved 2008-01-11.
  6. ^ Donald H. Martin (2000). Communication Satellites. AIAA. ISBN 1884989063.
  7. ^ Peter Ayotte, RIck Fields (September 1994). "Milstar DFS-1 On-Orbit Test Results". AIAA. AIAA-94-4520. {{cite journal}}: Cite journal requires |journal= (help)
  8. ^ Donald H. Martin (2000). Communication Satellites. AIAA. ISBN 1884989063.
  9. ^ Peter Ayotte, RIck Fields (September 1994). "Milstar DFS-1 On-Orbit Test Results". AIAA. AIAA-94-4520. {{cite journal}}: Cite journal requires |journal= (help)
  10. ^ Peter Ayotte, RIck Fields (September 1994). "Milstar DFS-1 On-Orbit Test Results". AIAA. AIAA-94-4520. {{cite journal}}: Cite journal requires |journal= (help)
  11. ^ Donald H. Martin (2000). Communication Satellites. AIAA. ISBN 1884989063.
  12. ^ James H. Hoffman (1994). "Milstar Terminal lnteroperability". AIAA. AIAA-1994-1016-517. {{cite journal}}: Cite journal requires |journal= (help)
  13. ^ Allen D. Dayton and Pravin C. Jain (September 1980). "MILSATCOM Architecture". IEEE Transactions on Communications. VOL. COM-28, NO. 9. {{cite journal}}: Cite journal requires |journal= (help)
  14. ^ US DOD (2006-02-24). "CHAPTER V: SATELLITE SYSTEMS" (PDF). Los Angeles Air Force Base. Retrieved 2007-08-21.
  15. ^ Allen D. Dayton and Pravin C. Jain (September 1980). "MILSATCOM Architecture". IEEE Transactions on Communications. VOL. COM-28, NO. 9. {{cite journal}}: Cite journal requires |journal= (help)
  16. ^ Donald H. Martin (2000). Communication Satellites. AIAA. ISBN 1884989063. {{cite book}}: Unknown parameter |Page= ignored (|page= suggested) (help)
  17. ^ Pravin C. Jain (July 1990). "Architectural Trends in Military Satellite Communications Systems". IEEE. Proceedings of the IEEE, Vol 78, No 7. {{cite journal}}: Cite journal requires |journal= (help)
  18. ^ Bruce Gary (June 1972). "From the Sea to the Stars". Department of the Navy. Retrieved 2008-01-11.
  19. ^ NASA (1995). "Beyond the Ionosphere". NASA. Retrieved 2008-01-11.
  20. ^ William W. Ward and Franklin W. Ford (1989). "Thirty Years of Research and Development in Space Communications at Lincoln Laboratory". The Lincoln Laboratory Journal". Vol. 2, No. 1 (Spring 1989) pp. 5-34. {{cite journal}}: Cite journal requires |journal= (help)
  21. ^ Department of the Navy (June 1996). [www.spawar.navy.mil/sti/publications/pubs/td/2899/td2899.pdf "Technical Document 2899. Command History. Calendar Year 1995"] (PDF). Department of the Navy. Retrieved 2008-01-11. {{cite web}}: Check |url= value (help)
  22. ^ Donald H. Martin (2000). Communication Satellites. AIAA. ISBN 1884989063.
  23. ^ GAO (July 31, 1986). "ACQUISITION Case Study of the MILSTAR Satellite Communications System". GAO. NSIAD-86-45S-15. {{cite journal}}: Cite journal requires |journal= (help)
  24. ^ Andrew J. Butrica (1997). Beyond The Ionosphere: Fifty Years of Satellite Communication. NASA. {{cite book}}: Cite has empty unknown parameter: |2= (help); Text "Chapter 7" ignored (help)
  25. ^ Department of the Navy (June 1996). [www.spawar.navy.mil/sti/publications/pubs/td/2899/td2899.pdf "Technical Document 2899. Command History. Calendar Year 1995"] (PDF). Department of the Navy. Retrieved 2008-01-11. {{cite web}}: Check |url= value (help)
  26. ^ Bruce Gary (June 1972). "From the Sea to the Stars". Department of the Navy. Retrieved 2008-01-11.
  27. ^ Bruce Gary (June 1972). "From the Sea to the Stars". Department of the Navy. Retrieved 2008-01-11.
  28. ^ Ronald Reagan (1981-10-01). "Strategic Forces Modernization Program (NSC-NSDD-12)". NSC. Retrieved 2008-01-11.
  29. ^ GAO (July 31, 1986). "ACQUISITION Case Study of the MILSTAR Satellite Communications System". GAO. NSIAD-86-45S-15. {{cite journal}}: Cite journal requires |journal= (help)
  30. ^ GAO (July 31, 1986). "ACQUISITION Case Study of the MILSTAR Satellite Communications System". GAO. NSIAD-86-45S-15. {{cite journal}}: Cite journal requires |journal= (help)
  31. ^ Bruce G. Blair (1985). Strategic Command and Control: Redefining the Nuclear Threat. Brookings Institution Press. ISBN 0815709811.
  32. ^ Paul G. Kaminski, undersecretary of defense for acquisition and technology (March 23, 1995). "Space Forces Essential to Modern Military". Defense Issues. Volume 10, Number 41. {{cite journal}}: Cite journal requires |journal= (help)
  33. ^ Private communication
  34. ^ Davis, Julius W., Jr (March 1995). "Congressional Budget Oversight of the Military Strategic and Tactical Relay (MILSTAR) Satellite Communications System. Fiscal Years 1982-1995". Defense Technical Information Center. ADA298877. {{cite journal}}: Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link)
  35. ^ Davis, Julius W., Jr (March 1995). "Congressional Budget Oversight of the Military Strategic and Tactical Relay (MILSTAR) Satellite Communications System. Fiscal Years 1982-1995". Defense Technical Information Center. ADA298877. {{cite journal}}: Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link)
  36. ^ GAO (June 1992). "Milstar Program Issues and Cost-Saving Opportunities". GAO. NSIAD-92-121. {{cite journal}}: Cite journal requires |journal= (help)
  37. ^ Bruce Gary (June 19972). "From the Sea to the Stars". Department of the Navy. Retrieved 2008-01-11. {{cite web}}: Check date values in: |date= (help)
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