Observation planning for any NASA mission is essential for demonstrating a spacecrafts ability to achieve goals, whether the target is Earth or any other astronomical body. As demands have grown, so has the fidelity, complexity, and precision of spacecraft observations. In addition, modern spacecraft communications bandwidth allows for the transmission of more data than ever. These increased capabilities have placed extra demands on spacecraft science observations; for example, the recent OSIRIS-REx mission regularly executed observation plans with sub-second timing for up to 300 targets each day. Although creating observation plans is usually relegated to the flight operations period of a mission, teams can benefit by considering these observation designs through early stages of mission planning as well. Exceptional collaboration between science teams and operations teams requires a complex web of cumbersome technology for sharing and integrating observation plans and their resulting data. This significant complexity hinders the ability of responsible parties to make informed, sensible, and rapid decisions. Spaceline solves this problem with an application that every party involved can access. Additionally, Spacelines flexible access allows users of both browser-based GUI or WebAPI to work with Spaceline directly or link Spaceline to their own tools, maintaining a known provenance for every kernel. Spaceline is a server- and web-based application developed under two in-progress NASA SBIR Phase II contracts. The Spaceline application consists of three core capabilities: SPICE kernel management, 3D interactive display of a scene, and simulation of science data for any onboard instrument for a given instant in time. We propose to extend the core functionality of Spaceline from supporting only pre-compiled observation plans (in the form of uploaded CKs) to allowing users to create observation plans directly within Spaceline. Potential NASA Applications (Limit 1500 characters, approximately 150 words): This work will be a welcome addition to any NASA mission looking to reduce costs and risks involved with operations planning. Users will have access to an environment in which they can analyze and measure the impact of proposed observation plans against complex scientific phenomena. This work will facilitate NASA in their goal of developing Mission Design Analysis tools to increase the accuracy of science modeling and enable design of future observing systems by predicting and optimizing their impacts on science data collection. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): The expansion of Spaceline to support operations planning would also facilitate mission planning for commercial Earth-orbiting constellations and Space Domain Awareness missions. Spaceline can also be used in classrooms, allowing students to explore a variety of data models for a planet, even adding their own models created from source data. Duration: 24