In this paper a new multiple access scheme dubbed contention resolution diversity slotted ALOHA (CRDSA) is introduced and its performance and implementation are thoroughly analyzed. The scheme combines diversity transmission of data bursts with efficient interference cancellation techniques. It is shown that CRDSA largely outperforms the classical lotted ALOHA (SA) technique in terms of throughput under equal packet loss ratio conditions (e.g. 17-fold improvement at packet loss ratio = 2 middot 10-2). CRDSA allows to boost the performance of random access (RA) channels in the return link of interactive satellite networks, making RA very efficient and providing low latency for the transmission of small size sparse packets. Implementation-wise it is shown that the CRDSA technique can be easily integrated in systems equipped with digital burst demodulators.