Bone Trajectories and Model Simulations Kathleen Mandt, Ray Goldstein, Christoph Koenders May 29, 2013 IES Team Meeting – San Antonio

Objectives and Projected Benefits Determine for each planning stage which science objectives can and cannot be achieved – Help frame arguments for pointing, trajectory selection and future bones – Determine what data we will obtain, such as our ability to measure the solar wind parameters Evaluate overall which objectives will not be achieved due to trajectories (e.g. observing the bow shock) Science – Model-data comparisons have important scientific value – How can the models be refined to improve the science return of the data? 2

Plasma model simulations Three models available – MHD – 2D simulations with H 2 O, CO and CO 2 – “Hybrid” – 2D hybrid simulations with H 2 O, CO and CO 2 – “Hybrid-AIKEF” – 3D hybrid simulations with single constituent Distance (AU) ModelOutgassing rate (s -1 ) 1.3 MHD5 x Hybrid5 x MHD8 x Hybrid8 x Hybrid8 x AIKEF1.5 x x AIKEF1.12 x x AIKEF7.36 x x MHD6 x x AIKEF3.6 x

Trajectory planning (so far…) 4 Three types of trajectories – Icosahedral – Orbit – Flyby Available trajectories – Prelanding: all of 2014 including comet approach – High Activity Case (HAC) 8 month plan – Low Activity Case (LAC – in progress)

Sample of predicted observations for the comet approach Distance to sun ~3.5 AU 6/25/14-8/25/14 Hybrid model – 3.3 AU – Limit 400 km 5 Approach from behind the comet heading toward the Sun Approach close to the comet and maneuver – may require too much fuel

The results for the comet approach and characterization Total ion density Cometary ion density Solar wind ion density Solar wind ion density is predicted by the model to be nearly constant over the entire range Cometary ion density increases by two orders of magnitude between 350 km and closest approach 6

Sample of predicted observations with a 10 km orbit (now ruled out by FD) Distance to sun ~2.9 AU Orbit the comet at ~10 km Any orbit distance (10-30 km) is too close to see any of the boundaries or to identify the ion tail We can watch for temporal and spatial variability in the coma 7 Hybrid-AIKEF simulation Total ion velocity Cometary ion velocity Solar wind ion velocity

More work to be done Keep up with changes in the planning process – e.g. Icosahedral now ruled out by FD Evaluate what distance is needed to see boundaries of interest Determine what new science can be gained within trajectory limitations 8 Total magnetic field B x B y B z

Backup slides 9

Rosetta distance to the Earth and to the Sun over the time of the mission 10

11 IES Team Meeting