DSP 21


Spacecraft n:

USA satellite n:

Defense Support Programm
Also known as IMEWS-21, DSP 3-8 or USA 159

Launch data:

Designation 26880 / 01033A
Launch date 06 Aug 2001 - 07:28 UT
Launch siteCC, SLC-40
Launch vehicleTitan-402B/IUS (S/N 4B-31 / #32)
MissionMilitary: Early Warning
Geostationary orbit:
Perigee / Apogee 35765 x 35810 km
Eccentricity 5.34E-04
Inclination 3.68 deg
Period 1436.14 min


Prime contractor TRW and Aerojet Electronics Systems
Operator  Air Force
Mass at launch 2380 kg
Mass in orbit  
Dimension 6.7 m dia x 10 m long (deployed)
Solar array  
Stabilization spin stabilized
DC power 1485 W
Design lifetime  7-9 yrs - still active


 April 2010  69.48° E 

Probably downlinks in S- and X-band. Has a wide field infrared telescope to provide real-time warning of missile launches (6000 infrared detectors)
Infrared sensors to detect heat from missile and booster plumes against earth's background; detection capability of smaller missiles; improved warning of attack by short-range missiles against U.S. and allied forces.

Ref: #7, #14, #15, #226 - update: 19.05.10