1. March 2004 At A Glance Advanced Mission Design (AMD) researches and develops innovative trajectories and the mathematical methods used for optimal designs. Benefits AMD enhances the capabilities of the mission designer to meet stringent science constraints while optimizing spacecraft and mission consumables (fuel, power, flight time, etc.). Methods developed provide fast, accurate, and flexible mission design tools. Features Some features of AMD are new trajectory design tools using direct and indirect methods such as Primer Vector theory and genetic algorithms, unique orbits and transfer manifolds to these orbits, and sound mathematical methods. Advanced Mission Design Summary The ultimate goal of Advanced Mission Design is to develop and integrate improved methods that allow us to design more complex missions and to minimize the cost of flying these missions. From a simple request to reduce the amount of fuel to achieve an orbit or to compute unique trajectories using new mathematical methods, this task aids us in helping spacecraft engineers and scientists to accomplish their goals. From this effort, we incorporate basic components of optimization methods into our mission design software tools. We also add capabilities to directly use a branch of mathematics called dynamical systems. Using these methods, new orbits were established that encouraged science proposals and allowed new missions. Besides designs of single trajectories, this activity also supports a suite of general design tools that enable optimal geometric designs that meet the constraints for Distributed Space Systems (DSS), which have multiple spacecraft in formations. This work crosses many projects at GSFC and NASA enterprises as it involves all orbit types, many spacecraft, and provides for new technologies. A portion of this work was a continuation of the Goddard Mission Services Evolution Center (GMSEC) and Earth Science Technology Office (ESTO) funded activities for applications to both Earth and Space Science Enterprises (ESE and SSE). The Technical Readiness Level (TRL) of the research varies, as some optimization techniques are clearly understood but how we should best apply them to orbit design is not. Recent successful optimization analysis has been performed in support of the Global Precipitation Measurement (GPM) constellation, the Solar Dynamics Observatory (SDO) orbit transfers, the James Webb Space Telescope (JWST) libration orbit, and the Laser Interferometer Space Antenna (LISA). The LISA formation and control optimization consists of three spacecraft flying 5 million kilometers (km) apart in the shape of an equilateral triangle. This work helps satisfy the charter of GSFC to reduce the cost of access to space, provide innovative technologies, build capabilities, and transfer this knowledge to the academic and commercial communities. The technical investigations and developments further support the resident expertise particularly within the context of libration point orbit analysis, transfer trajectory design, and general formation establishment and maintenance. The work enhances the theoretical understanding of the multi-body problem and offers the advantages available by incorporating the dynamical relationships into formation flying design. The models and techniques developed provide immediate results for mission support, thus enhancing GSFC participation in proposals while expanding capabilities. The Advanced Mission Design work described here covers flight dynamics areas important to all trajectory design. These include optimization of orbits to meet science and engineering requirements while minimizing maneuver impacts, application of new mathematical methods to ensure optimal design, investigation of unique orbit design, and the development of new utilities and algorithms to support GSFC missions. NASA GSFC Mission Services Evolution Center, Code 581 Greenbelt, Maryland 20771 http://gmsec.gsfc.nasa.gov email: gmsec@nasa.gov

2. March 2004 Unique Orbits We analyzed unique orbits using a dynamical systems approach. Orbits in the vicinity of the collinear libration points in the Sun-Earth and Earth-Moon systems serve as excellent vantage locations for scientific investigations involving the Sun, planetary, and Earth/Moon environments. We will continue to focus significant development and operations activities for NASA in support of such missions. GSFC missions involving libration point orbits include Constellation-X-ray, Micro- arcsecond X-Ray Imaging Mission formation (Maxim), Stellar Imager formation, and James Webb Space Telescope (JWST). The use of multiple spacecraft in a distributed approach to perform interferometry and optical measurements not achievable by a single spacecraft was one of the major drivers in this effort. Trajectory design and pre-launch analysis, as well as on-orbit operations and performance evaluation, for these missions is increasingly challenging as more complex missions are envisioned throughout the upcoming decades. GMSEC Advanced Mission Design Features Several of these unique and innovative trajectories and optimal methods are shown in the figures. The results of the AMD efforts are used today for the missions described above and for research into new possibilities. Primer Vector Analysis Tool True Multiple Spacecraft Propagator Libration Transfer Manifold Generator Trajectory Optimization Toolbox Earth-Moon Transfers Libration Orbit Transfers Near Retrograde Orbits