Defense Support Program (DSP)

Missile warning satellite constellationRetiredFielded 1972Pending verification

Fact cardConfidence · Source

System

TypeMissile warning satellite constellation

Date of introduction1972

ProliferationOrigin country only

Satellites2323 deployed; five listed operational (DSP-18 to DSP-22) before sunsetMed^[1]

First launch1970Med^[1]

ContractorsNorthrop Grumman (formerly TRW), AerojetMed^[1]

Program statusDetected Iranian missiles at Al Asad (January 2020) and strikes on Israel (April and October 2024) with SBIRS; sunset reported 1 October 2026Med^[1]

Dimensions and weight

Mass2,359 kg5,201 lbAbout 5,200 lbMed^[1]

Orbit

Orbit regimeGEOMed^[1]

Catalogued on orbit11Payloads with current element sets in the public catalog, active or not.High^[2]

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

Perigee36,126–36,127 kmActive satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Apogee36,137–36,167 kmActive satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Orbital period1,453.8–1,454.6 minActive satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Inclination12.25–13.31 °Active satellites per CelesTrak, element epoch about 2026-11-08.High^[2]

Catalogued satellites · 11^[2]

Name	NORAD	COSPAR	Perigee km	Apogee km	Incl. °	Period min	Status
USA 7 (DSP 12)	15453	1984-129A	36,168	36,206	11.26	1456.6	Inactive
USA 28 (DSP 13)	18583	1987-097A	36,202	36,446	11.93	1463.6	Inactive
USA 39 (DSP 14)	20066	1989-046A	36,180	36,216	12.8	1457.2	Inactive
USA 65 (DSP 15)	20929	1990-095A	36,312	36,330	13.92	1463.5	Inactive
USA 75 (DSP 16)	21805	1991-080B	36,086	36,099	13.93	1451.7	Inactive
USA 107 (DSP 17)	23435	1994-084A	36,084	36,164	14.49	1453.3	Inactive
USA 130 (DSP 18)	24737	1997-008A	36,088	36,189	14.49	1454.1	Inactive
USA 142 (DSP 19)	25669	1999-017A	581	34,723	29.46	617.9	Inactive
USA 149 (DSP 20)	26356	2000-024A	36,126	36,137	13.31	1453.8	Active
USA 159 (DSP 21)	26880	2001-033A	36,081	36,100	12.92	1451.7	Inactive
USA 176 (DSP 22)	28158	2004-004A	36,127	36,167	12.25	1454.6	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

The first U.S. space-based missile launch detection system, operated from 1970; Air & Space Forces reported its sunset in October 2026.

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

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Operators

United States

Sources

Defense Support Program (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): 11 catalogued, 2 active.