Gemini (?.)
- ATDA
- ATS
- Alouette
- Anna
- Apollo
- Ariel
- Atlas-Score
- Biosatellite
- Castor and Pollux
- Comsat
- Cosmos
- Courier
- Diapason
- Discoverer
- ERS
- Early Bird
- Echo
- Elektron
- Explorer
- GATV
- Injun
- Intelsat
- Lofti
- Luna
- Lunar Orbiter
- Lunik
- Mariner
- Mars probes
- Mercury
- Midas
- Nimbus
- OAO
- OGO
- OSO
- Pageos
- Pegasus
- Pioneer
- Proton
- Ranger
- Relay
- Samos
- San Marco
- Secor
- Siamese twins
- Sputnik
- Surveyor
- Syncom
- Telstar
- Transit
- Tweedledum and Tweedledee
- Twin Stars
- Vanguard
- Viking
- Voskhod
- Zond
- artificial satellites
- exact mates
- fraternal twins
- identical twins
- pair of twins
- spacecraft
- twins