Power is not an issue for a very low-bandwidth system like Iridium, which only provides 2400bps. Starlink's bandwidth is 10,000x higher, and in a nutshell that'

Power is not an issue for a very low-bandwidth system like Iridium, which only provides 2400bps. Starlink's bandwidth is 10,000x higher, and in a nutshell that's why they need a lot more power. Starlink also uses an active phased-array antenna, while Iridium uses a passive ("dumb") omnidirectional antenna. This also contributes to a greater power budget for Starlink.