Satellite Internet systems are studied, considering the advantages in constructing them with on-board ATM switches. As an effective application, reliable multicast with the satellite Internet systems is discussed, compared to that with the terrestrial Internet systems. Reliable multicast protocols are reviewed, keeping in view of their use in the satellite Internet systems. Full-meshed connections established by the on-board ATM switches can put many-to-many multicast into practice with reliability in transmission. The performance of the satellite Internet systems are evaluated for the reliable multicast with a simplified NACK-based transport protocol as a first step. The results of the evaluation for the satellite Internet systems are compared with those for the terrestrial Internet systems. Finally, the advantages of the satellite Internet systems are clarified in reliable-multicast performance in contrast to the terrestrial Internet systems.