# Milstar

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Constellation of American military satellites

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Milstar Artist's impression of a Milstar Block I spacecraft Manufacturer Lockheed Martin (prime, formerly Lockheed Missiles and Space) Northrop Grumman (formerly TRW) Boeing (formerly Hughes) Country of origin United States Operator U.S. Space Force Applications Military communications Specifications Bus Milstar Block I Milstar Block II Launch mass 4,500 kilograms (9,900 lb) Regime Geosynchronous Design life 10 years Production Status Out of production Active Built 6 Launched 6 Operational 5[citation needed] Lost 1 Maiden launch USA-99, 1994-02-07 Last launch USA-169, 2003-04-08

**Milstar** (Military Strategic and Tactical Relay)[1] is a [constellation](/source/Satellite_constellation) of [military](/source/Military_satellite) [communications satellites](/source/Communications_satellites) in [geosynchronous orbit](/source/Geosynchronous_orbit), which are operated by the [United States Space Force](/source/United_States_Space_Force), and provide secure and jam-resistant worldwide communications to meet the requirements of the [Armed Forces of the United States](/source/Armed_Forces_of_the_United_States). Six spacecraft were launched between 1994 and 2003, of which only five were operational after launch; the third launch failed, both damaging the satellite and leaving it in an unusable orbit.

## History

Milstar Block I spacecraft, or Milstar Developmental Flight Satellite (DFS)-1 and -2, were designed with a Low Data Rate (LDR) payload in the +X wing of the satellite that broadcast in the [Super High Frequency](/source/Super_High_Frequency) (SHF) and [Extremely High Frequency](/source/Extremely_High_Frequency) (EHF) ranges, and also a classified communication payload in the -X wing. The DFS-1 satellite was launched on 7 February 1994 aboard the first [Titan IV(401)A](/source/Titan_IV) rocket, but with the classified -X wing payload deactivated. It was followed by the DFS-2 spacecraft on 7 November 1995. DFS-2 was similar to DFS-1, but the classified payload was replaced by [ballast](/source/Ballast) in the form of a precision machined [aluminum](/source/Aluminum) block to maintain the weight and balance characteristics of the satellite. Both Block I satellites (USA-99 and USA-115) are still operational as of March 2025, over 25 years since they were launched.

The four later satellites were Block II spacecraft, which featured an additional medium data-rate payload. The first Block II satellite (DFS-3m, a hybrid mix of largely Block I support systems and LDR payload and a MDR (Medium Data Rate) Block II payload) was launched on 30 April 1999, using a [Titan IV(401)B](/source/Titan_IV) rocket. Due to a database error affecting the attitude control system of the [Centaur](/source/Centaur_(rocket_stage)) upper stage of its carrier rocket, it was placed into a lower orbit than had been planned, and damaged by deployment at excessive rates. It could not be raised into its operational orbit due to fuel limitations. Its orbit was raised as much as possible to increase the expected lifetime and then it was permanently turned off after 10 days.[2][3] It was the third consecutive, and last, failure of a Titan IV rocket. The remaining three satellites (DFS-4, -5, and -6) were launched on 27 February 2001, 15 January 2002, and 8 April 2003.

The Milstar system consists of three segments; the space segment which consists of the six satellites, ground terminals and users, and stations to command and control the satellites. The [Military Satellite Communications Systems Wing](/source/Military_Satellite_Communications_Systems_Wing) (MCSW) division of the [Space and Missile Systems Center](/source/Space_and_Missile_Systems_Center), located at [Los Angeles AFB](/source/Los_Angeles_AFB) was responsible for development and acquisition of the Milstar space and mission control segments. The [Electronic Systems Center](/source/Electronic_Systems_Center) at [Hanscom AFB](/source/Hanscom_Air_Force_Base) is responsible for the US Air Force portion of the terminal segment development and acquisition. The [4th Space Operations Squadron](/source/4th_Space_Operations_Squadron) at [Schriever SFB](/source/Schriever_Space_Force_Base) and the [148th Space Operations Squadron](/source/148th_Space_Operations_Squadron) at [Vandenberg SFB](/source/Vandenberg_SFB) are responsible for providing real-time satellite control and communications payload management.

In August 2010 control of the Milstar system was transferred to the [Advanced Extremely High Frequency](/source/Advanced_Extremely_High_Frequency) program, in preparation for the launch of the first AEHF satellite, [USA-214](/source/USA-214). Advanced Extremely High Frequency satellites are intended to replace Milstar.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## Characteristics

Milstar satellites provide secure, jam resistant, worldwide communications to meet the requirements of the United States military. They were built by [Lockheed Martin Missiles and Space Corporation](/source/Lockheed_Martin), at a cost of [US$](/source/US_dollar)800 million each. Each satellite has a design life of 10 years. Six were built, of which five reached their operational [geosynchronous orbits](/source/Geosynchronous_orbit), and remain in service. Launches were made using [Titan IV](/source/Titan_IV) rockets with Centaur upper stages, and all six occurred from [Space Launch Complex 40](/source/Cape_Canaveral_Air_Force_Station_Space_Launch_Complex_40) at the [Cape Canaveral Air Force Station](/source/Cape_Canaveral_Air_Force_Station). The satellites are designed to provide communications which are hard to detect and intercept, and to be survivable in the event of [nuclear warfare](/source/Nuclear_warfare).

The spacecraft have a mass of 4,500 kilograms (9,900 lb), and are equipped with [solar panels](/source/Solar_panel) which generate eight [kilowatts](/source/Kilowatt) of [electric power](/source/Electric_power) to power its [transponders](/source/Transponder_(satellite_communications)). Both Block I and Block II satellites provide low data-rate communications at bandwidths between 75 bit/s and 2,400 bit/s, whilst the Block II spacecraft can also provide medium data-rate communications between 4.8 kbit/s and 1.544 Mbit/s. The satellites' uplinks operate in the [Q band](/source/Q_band), while their downlinks operate within the [K band](/source/K_band_(IEEE)). The uplink corresponds to the [extremely high frequency](/source/Extremely_high_frequency) band while downlink corresponds to the [super high frequency](/source/Super_high_frequency) radio band.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

### Spacecraft

"USA-99" redirects here. For the World Cup, see [1999 FIFA Women's World Cup](/source/1999_FIFA_Women's_World_Cup).

USA ID Name Block Launch date/time (UTC) COSPAR ID Rocket Remarks USA-99 DFS-1 Block I 1994-02-07, 21:47:01 1994-009A Titan IV(401)A USA-115 DFS-2 Block I 1995-11-06, 05:15:01 1995-060A Titan IV(401)A USA-143 DFS-3M Block I/II hybrid 1999-04-30, 16:30:00 1999-023A Titan IV(401)B Launch failure USA-157 DFS-4 Block II 2001-02-27, 21:20 2001-009A Titan IV(401)B USA-164 DFS-5 Block II 2002-01-16, 00:30:00 2002-001A Titan IV(401)B USA-169 DFS-6 Block II 2003-04-08, 13:43:00 2003-012A Titan IV(401)B

## See also

- [Advanced Extremely High Frequency](/source/Advanced_Extremely_High_Frequency)

- [Defense Satellite Communications System](/source/Defense_Satellite_Communications_System)

- [Transformational Satellite Communications System](/source/Transformational_Satellite_Communications_System)

- [Wideband Global SATCOM system](/source/Wideband_Global_SATCOM_system)

## References

1. **[^](#cite_ref-1)** ["MILITARY STRATEGIC AND TACTICAL RELAY (MILSTAR) SATELLITE SYSTEM - FY00 Activity"](https://www.globalsecurity.org/military/library/budget/fy2000/dot-e/airforce/00milstar.html).

1. **[^](#cite_ref-2)** ["NASA - NSSDCA - Spacecraft - Details"](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1999-023A). *nssdc.gsfc.nasa.gov*. Retrieved 2023-03-23.

1. **[^](#cite_ref-3)** ["Milstar-2 1, 2, 3, 4 (Milstar 3, 4, 5, 6)"](https://space.skyrocket.de/doc_sdat/milstar-2.htm). *Gunter's Space Page*. Retrieved 2023-03-23.

- King, Mak and Riccio, Michael J. (Spring 2010). "Military Satellite Communications: Then and Now". *Crosslinks Magazine*. Aerospace Corp.

## External links

- [U.S. Air Force fact sheet on MILSTAR](https://www.losangeles.spaceforce.mil/?id=5328)

- [MILSTAR 3 / Advanced Extremely High Frequency (AEHF)](https://web.archive.org/web/20110826180043/http://satsin.com/milstar-3-advanced-extremely-high-frequency-aehf/)

v t e USAF and USSF space vehicle designations (since 1962) SLV series SLV-1 (Scout) SLV-2 (Thor) SLV-3 (Atlas) SLV-4 (Titan II) SLV-5 (Titan) SB series SB-1 SB-2 SB-3 SB-4 SB-5 SB-6 SSB-7 SSB-8 SSB-9 SSB-10 ASB-11 Satellites WS-1 WS-2 LS-3 ES-4 ES-5 LS-6 NS-7 ES-8 LS-9 LS-10 (I) XSS-10 (II) XSS-112 XSS-12 S-131 ES-14 LS-153 LS-163 ES-17 EWS-G1 EWS-G2 1 Not assigned 2 Unofficial designation 3 Designation believed to be this type but unconfirmed

v t e Lockheed Martin Headquarters: Bethesda, Maryland People Board of Directors Marillyn Hewson (Executive Chair) Daniel Akerson (Member) David Burritt (Member) Joseph Dunford (Member) Senior management James Taiclet (President & CEO) Frank St. John (COO) Evan Scott (CFO) Corporate headquarters Divisions, subsidiaries Current LM Advanced Technology Laboratories LM Aeronautics (Skunk Works) LM Information Technology LM Missiles and Fire Control LM Rotary and Mission Systems (Sikorsky Aircraft) LM Orincon LM Space Systems Former COMSAT Lockheed Aircraft Argentina SA LM Global Training and Logistics LM Systems Integration – Owego LM Transportation & Security Solutions Neustar Pacific Architects and Engineers Real3D Joint ventures Current Longbow LLC Lockheed Martin–Alenia Tactical Transport Systems Protector USV Tata–Lockheed Martin Aerostructures United Launch Alliance United Space Alliance USC–Lockheed Martin QCC Former International Launch Services Space Imaging Facilities Goodyear Airdock LM Solar and Astrophysics Laboratory Active products Aircraft C-5 Galaxy C-130J Super Hercules CATBird Desert Hawk UAV (Desert Hawk III) F-16 Fighting Falcon F-22 Raptor F-35 Lightning II (JCA) KC-130J tanker LM-100J Hercules LMXT MC-130J Commando II MC-130W Combat Spear Minion UCAV P-3 Orion P-791 airship T-50 Golden Eagle U-2 Dragon Lady VH-92 Patriot X-55 ACCA X-56 X-59 Quesst Electronics AN/AAS-38 Nite Hawk Apache Arrowhead AN/APG-78 Longbow AN/APY-9 AN/FPS-117 AN/SPY-1 AN/TPQ-53 AN/TPY-4 AN/SQQ-89 AN/WLD-1 RMS Auto-GCAS LANTIRN Long Range Discrimination Radar Sniper Advanced Targeting Pod Space Fence Software Prepar3D Radiant Mercury Solarsoft Space systems A2100 Atlas V rocket GPS Block III Milstar MUOS (MUOS-5) Nimiq-1 Orion MPCV SBIRS Weapon systems Aegis Combat System AIM-260 JATM AGM-114 Hellfire AGM-158 JASSM AGM-158C LRASM AGM-169 JCM AGM-179 JAGM ATACMS DAGR FGM-148 Javelin GMARS HELIOS HELLADS M142 HIMARS M270 MLRS Mako MEADS MHTK Mk 41 VLS OpFires PrSM RUM-139 VL-ASROC SACM THAAD Trident missile Other Eureka Streams HULC Perforene Category Commons

v t e United States Air Force system numbers 100–199 100 101 P 102 103 104 105 1061 107 A-1 A-2 1081 1091 110 1111 112 1131 1141 1151 1161 117 L M 118 A L P 119 C/F E L T Y 120 121 122 123 124 125 126 1271 128 129 130 131 132 A B 133 1341 135 1361 1371 138 139 140 1411 142 143–1971 198 199 B C D Y 200–299 200 201 A/L B/W E 202 2031 204 205 206 2071 208 2091 210 2111 212 213 214 2151 216 217 218 2191 220 221 222 A G 2231 224 2251 226 227–2381 239 240–2781 279 280–2981 299 300–399 300 3011 302 303 3041 3051 306 A/L B 307 308 309 3101 3111 3121 3131 314 315 A-1 A-2 316 317 3181 319 3201 321 3221 323 324 L M/N 325 326 327 E 328 E 329 F 3301 3311 3321 3331 3341 335 336 337 338–3791 380 A/B/E/F/N P 381–3971 398 399 A B 400–499 400 B/C/N E G/H M 401 402 4031 404 405 B C D 4061 407 4081 4091 410 E L 411 E L 412 413 414 L M 415 416 L M (I) M (II) P Q 417 418 L M 4191 420 L/W 4211 422 423 424 425 426 L M 427 L M 428 A L 429 430 431 G (I) G (II) 432 433 434 435 A L 436 437 438 439 440 441 A D L 442 443 4441 445 L M 446 447 4481 4491 450 451 D L 452 453 4541 455 456 4571 458 459 460 L 461 462 463 464 465 466 467 468 469 470 471 L (I) L (II) 472 473 474 L N 4751 476 E 477 478 A T 4791 480 481 L 482 E L M/Z 483 484 L M N 485 L Z 486 487 488 489 490 L M 4911 492 493 494 495 L (I) L (II) 496 497 A L (I) L 498 A C D E L 499 A C D 500–599 500 501–5191 520 521–5291 530 531–5411 542 543–5491 550 A E 551–5591 560 A F 561–5691 570 571–5791 580 A E 581–5891 590 591 592 593–5991 600–699 600 601 A L 602 A L 603 A L 604 605 606 607 6081 609 6101 6111 6121 6131 614 6151 616 6171 618 6191 620 621 A/B (I) B (II) 622 623 624 625 6261 627 6281 6291 6301 6311 632 633 634 A B 635 6361 6371 638 639 640 641 642 643 6441 6451 6461 6471 648 A D P 649 A B C D E F L P 650 651 652 6531 6541 655 A (I) A (II) P 656 6571 6581 6591 660 661 6621 6631 664 665 A (I) A (II) 666 A C/P 667 668 6691 670 6711 672 A M/P 6731 674 675 6761 6771 6781 679 680 681 D E 6821 683 A J V 6841 685 686 687 J P 6881 6891 690 691 C X Z 6921 693 6941 695 A C L N P Q R S (I) S (II) 6961 6971 6981 6991 700–799 700–7351 736 7371 7381 7391 7401 741 742 743 7441 745 746–7531 754 755–7991 800–899 8001 8011 802 L (I) L (II) 8031 8041 8051 806 807 808–8161 817 8181 8191 8201 8211 8221 823 824–8311 832 8331 834 835–8451 846 847–8991 900–999 900–9511 952 8531 8541 8551 956 957–9671 968 1 Unknown or not assigned

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Adapted from the Wikipedia article [Milstar](https://en.wikipedia.org/wiki/Milstar) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Milstar?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.