This document defines a set of standard application layer interfaces called JAUS Core Services. JAUS Services provide the means for software entities in an unmanned system or system of unmanned systems to communicate and coordinate their activities. The Core Services represent the infrastructure commonly found across all domains and types of unmanned systems. At present, seven services are defined in this document: Transport Service: Abstracts the functionality of the underlying communication transport layer; Events Service: Establishes a publish/subscribe mechanism for automatic messaging; Access Control: Manages preemptable exclusive control for safety critical operations; Management: Defines component life-cycle management; Time: Allows clients to query and set the system time for the component; Liveness: Provides a means to maintain connection liveness between communicating components; Discovery: Governs automatic discovery of remote entities and their capabilities Each service is described by a JAUS Service Definition (JSD) which specifies the message set and protocol required for compliance. Each JSD is fully compliant with the JAUS Service Interface Definition Language (JSIDL). The purpose of this document is to facilitate interoperation of unmanned vehicle systems, subsystems, and payloads by standardization of the message set and associated protocol.