A two-way satellite communications system includes an Earth station communicating with a plurality of remote terminals using a network access protocol that facilitates low power consumption by the terminals. The devices can include an expandable, fluid-tight bladder configured to be deployed between valve leaflets of the heart valve. The flexible panel is positioned to receive ejected ground material and safely project it laterally from the ground engaging features to prevent the injury of individuals near the digging machine and prevent the ground material from refilling the newly formed opening in the ground. In an embodiment of the invention, copy-never content that exceeds a defined delay between transmission and reception is prevented from being displayed.