What mode of transmission is commonly used by amateur radio satellites?

Amateur radio satellites are highly versatile and carry a variety of transponders and repeaters to support many different operating modes. Single Sideband (SSB) and Continuous Wave (CW) are heavily used on linear transponder satellites because they are highly bandwidth-efficient and allow multiple users to operate simultaneously. FM is also extremely common, especially on Low Earth Orbit (LEO) satellites that act as single-channel "flying repeaters." These FM satellites are particularly popular for beginners because they can often be accessed with basic handheld transceivers and simple antennas. Additionally, data modes (like packet radio, APRS, or telemetry downlinks) are widely supported across the amateur satellite fleets. Therefore, SSB, FM, CW, and data are all correct answers.