Milstar

Protected military communications constellationIn serviceFielded 1997Pending verification

SpaceUSA

Identification silhouette. Not drawn to scale between entries.

Fact cardConfidence · Source

System

TypeProtected military communications constellation

Date of introduction1997

ProliferationOrigin country only

Satellites5Two Milstar I and three Milstar II (page also mentions six launched through 2003)Med^[1]

First launch1994Med^[1]

Program statusPassed 30 years of operations on 7 February 2024Med^[1]

Dimensions and weight

Mass4,536 kg10,000 lbAbout 10,000 lbMed^[1]

Power8,000 WMed^[1]

Mission

MissionMilstar I: 75 bps–2.5 kbps over 192 EHF channels; Milstar II adds medium data rate up to 1.5 Mbps over 32 channelsMed^[1]

Orbit

Orbit regimeGEOHigh^[1]

Design life10 yearsMed^[1]

Catalogued on orbit6Payloads with current element sets in the public catalog, active or not.High^[2]

Active (CelesTrak)4Count in the CelesTrak active satellites list, which estimates operational status.Med^[2]

Perigee35,373–35,768 kmActive satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Apogee35,806–36,202 kmActive satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Orbital period1,436–1,436.1 minActive satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Inclination11.35–14.12 °Active satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Catalogued satellites · 6^[2]

Name	NORAD	COSPAR	Perigee km	Apogee km	Incl. °	Period min	Status
USA 99 (MILSTAR-1 1)	22988	1994-009A	36,210	36,243	17.84	1458.6	Inactive
USA 115 (MILSTAR-1 2)	23712	1995-060A	35,768	35,806	14.12	1436.1	Active
USA 143 (MILSTAR-2 1)	25724	1999-023A	1,099	5,146	28.23	153.6	Inactive
USA 157 (MILSTAR-2 2)	26715	2001-009A	35,606	35,964	11.7	1436	Active
USA 164 (MILSTAR-2 3)	27168	2002-001A	35,373	36,202	11.35	1436.1	Active
USA 169 (MILSTAR-2 4)	27711	2003-012A	35,386	36,187	12.55	1436.1	Active

Mean elements at epoch 2026-11-08 or later. Perigee and apogee are computed from mean motion and eccentricity and are approximate. Status follows the CelesTrak active list.

Summary

First-generation protected EHF satellite communications system, now operated together with AEHF.

Draft entry. Values come from the cited public sources and are awaiting editor verification.

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Operators

United States

Sources

Milstar Satellite Communications System (weapons and platforms entry), Air & Space Forces Magazine
Tier 3 · checked 2026-11-08
NORAD GP element sets (current data), CelesTrak (data from the U.S. Space Force 18th/19th Space Defense Squadron catalog)
Published/updated 2026-11-08 · Tier 1 · checked 2026-11-08

Change log

2026-11-08 Entry created from cited open sources
2026-11-08 Orbital elements from CelesTrak GP data (epoch about 2026-11-08): 6 catalogued, 4 active.