Encyclopedia Astronautica
Milstar



milstar.jpg
Milstar
Credit: USAF
American military communications satellite. 6 launches, 1994.02.07 (USA 99) to 2003.04.08 (USA 169). Milstar was a series of advanced US military communications satellites designed to provide global jam-resistant communications for military users.

The Milstar system consisted of four Block 2 satellites in low-inclination, geosynchronous orbits. The operational system accommodated direct links to numerous, highly mobile Milstar ground terminals installed on vehicles, ships, submarines and aircraft. The first two Block 1 spacecraft, launched in 1995, were eventually replaced by the Block 2 Milstar 3 through 6, which were launched beginning in 1999. The full Block 2 constellation allowed as many as 10,000 users to access the system at any given time.

The spacecraft was 3-axis stabilized, with two large solar arrays. The second spacecraft (F2) carried 398 kg of ballast to replace a classified payload which was removed. The Block 1 satellites had costly nuclear hardness and survivability features which were not included in the four Block 2 satellites. Two crosslink dish antennas located at opposite ends of each spacecraft connected all four Block 2 satellites to form a secure constellation controlled from a single fixed or mobile control station. Crosslink operations were performed at or near frequencies that were absorbed by Earth's atmosphere, preventing detection by Earth-based ground stations. The satellite and ground station designs also incorporated advanced signal processing/encryption technologies to deny access of downlinked signals to unauthorized users.

The Low data rate (LDR) EHF payload was built by TRW and had 192 channels with rates between 75 and 2400 bps. Block 2 spacecraft carried the LDR in addition to a Medium Data Rate (MDR) payload built by Hughes. The MDR provided rates of 4800 bps to 1.544 Mbps per channel. The MDR payload also included two nulling spot antennas that could identify and pinpoint the location of a jammer and electronically isolate its signal, allowing Milstar users to operate normally and at full capacity with no loss in signal quality or speed, despite any attempt by hostile forces to jam or intercept its signal.

The Defense Department's Milstar, distinguished itself as the first of its kind in several groundbreaking advancements: the first satellite system to allow all branches of the U.S. Armed Services to communicate with one another on the same secure network; the first to operate at extremely high frequencies; and the first to provide satellite-to-satellite communications. Milstar's "switchboard-in-the sky" operational concept was considered revolutionary because the satellites handled all processing and traffic management chores without ground station relays, greatly enhancing data security and jam resistance.

Lockheed Missiles and Space, as prime contractor and systems integrator, led a team responsible for designing, building and launching the system. Two Milstar satellites were launched in 1994 and 1995 aboard Titan IV-Centaur boosters built by Lockheed Martin Astronautics. Software updates to the satellite memory increased Milstar's flexibility and operation.

AKA: Military Strategic and Tactical Relay System.
Gross mass: 4,500 kg (9,900 lb).
Height: 12.00 m (39.00 ft).
First Launch: 1994.02.07.
Last Launch: 2003.04.08.
Number: 6 .

More... - Chronology...


Associated Countries
See also
  • Titan The Titan launch vehicle family was developed by the United States Air Force to meet its medium lift requirements in the 1960's. The designs finally put into production were derived from the Titan II ICBM. Titan outlived the competing NASA Saturn I launch vehicle and the Space Shuttle for military launches. It was finally replaced by the USAF's EELV boosters, the Atlas V and Delta IV. Although conceived as a low-cost, quick-reaction system, Titan was not successful as a commercial launch vehicle. Air Force requirements growth over the years drove its costs up - the Ariane using similar technology provided lower-cost access to space. More...

Associated Launch Vehicles
  • Titan American orbital launch vehicle. The Titan launch vehicle family was developed by the United States Air Force to meet its medium lift requirements in the 1960's. The designs finally put into production were derived from the Titan II ICBM. Titan outlived the competing NASA Saturn I launch vehicle and the Space Shuttle for military launches. It was finally replaced by the USAF's EELV boosters, the Atlas V and Delta IV. Although conceived as a low-cost, quick-reaction system, Titan was not successful as a commercial launch vehicle. Air Force requirements growth over the years drove its costs up - the Ariane using similar technology provided lower-cost access to space. More...
  • Titan 4 American orbital launch vehicle. Developed to handle military payloads designed for launch on Shuttle from Vandenberg before the USAF pulled out of the Shuttle program after the Challenger disaster. Further stretch of core from Titan 34, 7-segment solid rocket motors (developed for MOL but not used until 25 years later). Enlarged Centaur G used as upper stage (variant of stage designed for Shuttle but prohibited for flight safety reasons after Challenger). Completely revised electronics. All the changes resulted in major increase in cost of launch vehicle and launch operations. More...
  • Titan 4B American orbital launch vehicle. Titan 4 with Upgraded Solid Rocket Motors replacing UA1207. Developed to improve performance for certain missions, and reduce number of field joints in motor after Challenger and Titan 34D explosions involving segmented motors. More...

Associated Manufacturers and Agencies
  • USAF American agency overseeing development of rockets and spacecraft. United States Air Force, USA. More...
  • Hughes American manufacturer of rockets, spacecraft, and rocket engines. Hughes Aircraft Co. , USA More...
  • TRW American manufacturer of rockets, spacecraft, and rocket engines. TRW Corporation, Redondo Beach, CA, USA. More...
  • Lockheed American manufacturer of rockets, spacecraft, and rocket engines. Lockheed Martin, Sunnyvale, CA, USA. More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: here.
  • National Space Science Center Planetary Page, As of 19 February 1999.. Web Address when accessed: here.
  • NASA/GSFC Orbital Information Group Website, Web Address when accessed: here.
  • Space-Launcher.com, Orbital Report News Agency. Web Address when accessed: here.

Associated Launch Sites
  • Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...
  • Cape Canaveral LC40 Titan launch complex. Constructed as part of the Titan Integrate-Transfer-Launch (ITL) facility at the north end of Cape Canaveral in the early 1960s. Supported a wide variety of military space missions involving Titan IIIC, Titan 34D and Titan IV vehicles. More...

Milstar Chronology


1994 February 7 - . 21:47 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC40. LV Family: Titan. Launch Vehicle: Titan Centaur 401A. LV Configuration: Titan 401A/Centaur K-10/TC-12 (45E-3).
  • USA 99 - . Payload: Milstar 1-01 / DFS 1. Mass: 4,500 kg (9,900 lb). Nation: USA. Agency: USAF. Class: Communications. Type: Military communications satellite. Spacecraft: Milstar. USAF Sat Cat: 22988 . COSPAR: 1994-009A. Apogee: 35,790 km (22,230 mi). Perigee: 35,733 km (22,203 mi). Inclination: 12.0000 deg. Period: 1,434.00 min. Summary: Military communications. Positioned in geosynchronous orbit at 90 deg W in 1994; 120 deg W in 1995-1999..

1995 November 6 - . 05:15 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC40. LV Family: Titan. Launch Vehicle: Titan Centaur 401A. LV Configuration: Titan 401A/Centaur K-21/TC-13 (45E-7).
  • USA 115 - . Payload: Milstar DFS 2. Mass: 4,500 kg (9,900 lb). Nation: USA. Agency: USAF. Class: Communications. Type: Military communications satellite. Spacecraft: Milstar. USAF Sat Cat: 23712 . COSPAR: 1995-060A. Apogee: 35,787 km (22,236 mi). Perigee: 35,787 km (22,236 mi). Inclination: 10.0000 deg. Summary: Secure military communication. Positioned in geosynchronous orbit at 4 deg E in 1995-2001. As of 2005 Mar 14 located at 10.26E drifting at 0.012E degrees per day..

1999 April 30 - . 16:30 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC40. LV Family: Titan. Launch Vehicle: Titan Centaur 401B. LV Configuration: Titan 401B/Centaur 4B-32/TC-14 (K-26). FAILURE: Centaur software programming error.. Failed Stage: 3.
  • USA 143 - . Payload: Milstar-2 F1 / DFS 3. Nation: USA. Agency: USAF. Manufacturer: Lockheed. Class: Communications. Type: Military communications satellite. Spacecraft: Milstar. USAF Sat Cat: 25724 . COSPAR: 1999-023A. Apogee: 5,149 km (3,199 mi). Perigee: 1,097 km (681 mi). Inclination: 28.2000 deg. The Titan core vehicle operated correctly, but a software error in the Centaur stage resulted in all three planned burns being made at the wrong times, during the first orbit instead of over a six hour period. The three burns planned to place Milstar successively in a 170 x 190 km parking orbit, a geostationary transfer orbit, and finally geosynchronous orbit. Instead, at 19:00 GMT, several hours before the scheduled third burn, Milstar separated into a useless 740 km x 5000 km orbit. Milstar-2 F1 was the first upgraded Milstar with an extra Medium Data Rate payload with a higher throughput. The payload included EHF (44 GHz), SHF (20 GHz) and UHF communications transponders and satellite-to-satellite crosslinks, with narrow beams to avoid jamming.

2001 February 27 - . 21:20 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC40. Launch Pad: SLC40. LV Family: Titan. Launch Vehicle: Titan Centaur 401B. LV Configuration: Titan 401B/Centaur 4B-41/TC-22 (K-30).
  • USA 157 - . Payload: Milstar-2 DFS 4. Mass: 4,670 kg (10,290 lb). Nation: USA. Agency: USAF. Manufacturer: Lockheed. Class: Communications. Type: Military communications satellite. Spacecraft: Milstar. USAF Sat Cat: 26715 . COSPAR: 2001-009A. Apogee: 35,768 km (22,225 mi). Perigee: 35,764 km (22,222 mi). Inclination: 4.5000 deg. Period: 1,435.05 min. Military Communications satellite. Launch delayed from October 30, December 14, 2000, and February 2 and February 24, 2001. The Milstar DFS 4 satellite (the second Milstar Block 2) provided secure communications for the US Department of Defense, with UHF, EHF and SHF band transmitters. Titan 4B-41 with core stage K-30 took off from Cape Canaveral and placed Milstar and the Centaur TC-22 upper stage in a suborbital trajectory. TC-22 then ignited to enter a 200 km parking orbit, and after two more burns delivered Milstar to geosynchronous drift orbit. Small engines on board the Milstar placed it at its targeted geostationary position. USA 157, a 4.5 tonne spacecraft, was the first in the Milstar 2 series which was capable of higher data rates and was more secure against disabling efforts.

2002 January 16 - . 00:30 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC40. Launch Pad: SLC40. LV Family: Titan. Launch Vehicle: Titan Centaur 401B. LV Configuration: Titan 401B/Centaur 4B-38/TC-19.
  • USA 164 - . Payload: Milstar 2-F3 / Milstar FLT-5 / DFS-5. Mass: 4,550 kg (10,030 lb). Nation: USA. Agency: USAF. Manufacturer: Lockheed. Class: Communications. Type: Military communications satellite. Spacecraft: Milstar. USAF Sat Cat: 27168 . COSPAR: 2002-001A. Apogee: 35,800 km (22,200 mi). Perigee: 35,773 km (22,228 mi). Inclination: 1.4600 deg. Period: 1,436.12 min. Military Communications satellite. Launch delayed from December 2001. The Titan core stage shut down 9 min after launch on a suborbital trajectory, and separated from the upper stage, Centaur TC-19. TC-19 made three burns to parking orbit, geostationary transfer orbit, and finally geostationary orbit. It then released Milstar Flt-5. Milstar provided secure communications in the EHF, SHF and UHF bands and would be stationed over European longitudes. As of 2007 Feb 16 located at 29.98E drifting at 0.014W degrees per day.

2003 April 8 - . 13:43 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC40. Launch Pad: SLC40. LV Family: Titan. Launch Vehicle: Titan Centaur 401B. LV Configuration: Titan 401B/Centaur 4B-35/TC-23.
  • USA 169 - . Payload: Milstar 6 / Milstar 2-F4. Mass: 4,500 kg (9,900 lb). Nation: USA. Agency: USAF. Manufacturer: Lockheed. Class: Communications. Type: Military communications satellite. Spacecraft: Milstar. USAF Sat Cat: 27711 . COSPAR: 2003-012A. Apogee: 35,811 km (22,251 mi). Perigee: 35,762 km (22,221 mi). Inclination: 0.9100 deg. Period: 1,436.13 min. Summary: Delayed from November 4, 2002, and January 21, February 2 and 4, March 5, 8 and 21, and April 6, 2003. As of 2007 Feb 4 located at 89.84W drifting at 0.014W degrees per day..

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