We have updated the UCS Satellite Database, including launches through September 30, 2019. Lots of movement this time, with 209 satellites added and 53 removed for a total of 2,218 actively working satellites.

UCS Satellite Database Update: More than 2,200 Active Satellites
December 19, 2019 6:09 PM EDT

Record Number of Satellites in Orbit
January 9, 2019 2:01 PM EDT
An updated version of the UCS Satellite Database has been posted. Including launches and deactivations through November 30, 2018, the Database includes information on about 1,957 active satellites. That is 71 more than our previous release last July. Read more >

How to Think about Space-Based Missile Defense
August 22, 2018 12:19 PM EDT
UPDATE: In September 2018, UCS released an animated feature and video that explains how space-based missile defense works. Check it out here.
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The idea of space-based missile defense system has been around for more than 30 years. There are at least two reasons for its continuing appeal. Read More

24 Space-Based Missile Defense Satellites Cannot Defend Against ICBMs
August 10, 2018 7:41 AM EDT
UPDATE: In September 2018, UCS released an animated feature and video that explains how space-based missile defense works. Check it out here.
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Articles citing a classified 2011 report by the Institute for Defense Analysis (IDA) have mistakenly suggested the report finds that a constellation of only 24 satellites can be used for space-based boost-phase missile defense. Read More
More Comments on the IDA Boost-Phase Missile Defense Study
August 10, 2018 7:40 AM EDT
Part 1 of this post discusses one aspect of the 2011 letter from Missile Defense Agency (MDA) to then-Senator Kyl about the IDA study of space-based missile defense. The letter raises several additional issues, which I comment on here. Read more >