Milstar-2 [Northrop Grumman]
Milstar (Military Strategic & Tactical Relay) is the tactical and strategic multiservice satellite system designed to provide survivable communications for U.S. forces worldwide. The program is managed by the U.S. Air Force Space and Missile Center.
The Milstar-1 satellites carry a secure, robust low-data-rate (LDR) communications payload, and a crosslink payload that allows the satellites to communicate globally without using a ground station. The Milstar-2 satellites extend the communications capabilities to higher data rates by adding a medium-data-rate (MDR) payload. The Milstar-1 and -2 satellites are fully interoperable for LDR communications and crosslinks.
Boeing has the prime responsibility for supplying the MDR and crosslink payloads to prime contractor Lockheed Martin Missiles and Space Company. BSS subcontracts with TRW Space and Electronics Group for the MDR antennas and digital subsystem, and provides portions of the LDR payload under subcontract to TRW.
Milstar satellites use a unique bus, consisting of three boxes, which are folded during launch and deploy in orbit.
The Milstar system provides uplink communications at extremely high frequency (EHF), 44 GHz, and ultrahigh frequency (UHF), 300 MHz, and downlink communications at super-high frequency (SHF), 20 GHz, and UHF, 250 MHz. The crosslinks operate in the 60 GHz region. Survivability and endurability requirements are satisfied by anti-jam, hardening and system autonomy features.
Originally the full Milstar system was to contain ten satellites, which were cut to four.
Milstar-2 1 was launched on 30 April 1999, but was stranded in a into a lower orbit than had been planned, and damaged by deployment at excessive rates due to a database error affecting the attitude control system of the Centaur upper stage. 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.
Milstar was succeded by the AEHF (Advanced Extreme High Frequency Satellite) satellites.
|Type / Application:||Comsat|
|Contractors:||Lockheed Martin (Bus), TRW (LDR payload), Hughes / Boeing (MDR payload)|
|Equipment:||LDR, MDR and Crosslink payloads|
|Propulsion:||2 × R-4D-12|
|Power:||2 deployable solar arrays, batteries|
|Mass:||4500 kg (design)|
|Milstar-2 1 (Milstar 3, USA 143)||1999-023A||30.04.1999||CC LC-40||f||Titan-4(01)B Centaur-T|
|Milstar-2 2 (Milstar 4, USA 157)||2001-009A||27.02.2001||CC SLC-40||Titan-4(01)B Centaur-T|
|Milstar-2 3 (Milstar 5, USA 164)||2002-001A||16.01.2002||CC SLC-40||Titan-4(01)B Centaur-T|
|Milstar-2 4 (Milstar 6, USA 169)||2003-012A||08.04.2003||CC SLC-40||Titan-4(01)B Centaur-T|
|Milstar-2 5 (Milstar 7)||-||cancelled||CC SLC-40||Titan-4(01)B Centaur-T|
|Milstar-2 6 (Milstar 8)||-||cancelled||CC SLC-40||Titan-4(01)B Centaur-T|
|Milstar-2 7 (Milstar 9)||-||cancelled||CC SLC-40||Titan-4(01)B Centaur-T|
|Milstar-2 8 (Milstar 10)||-||cancelled||CC SLC-40||Titan-4(01)B Centaur-T|