April 4, 2014 Flight Dynamics 1 MMS-THEMIS Phasing An apples-to-apples comparison between the Winter Nominal and THEMIS Launch Block Conrad Schiff MMS SWG Meeting 4 Apr 2014 Significant contributions by: Trevor Williams, Laurie Mann, Edwin Dove, Khasy Parsay, Jason Tichy

April 4, 2014 Flight Dynamics 2 Flight Dynamics Status Flight Dynamics (FD) is currently working the following items 1.Generation of ephemeris files, in five-day steps, for Winter and THEMIS blocks over the prime launch window Mar 3 rd – Apr 3 rd, 2015 (3/5, 3/10, 3/15, 3/20, 3/25, 3/30) 2.Comparisons of these ephemeris files and post-processed results with (in order of priority): a.SWM76 modeling – needed for LV Target Spec b.Analysis produced Stephen Fuselier and Steve Petrinec (Steve 2 ) c.UCB produced ephemeris files 3.Determination of fuel optimal ways to meet formation flying goal in THEMIS Phase 0a science 4.Risk assessment of THEMIS block; including timeline, launch vehicle, fuel and operations considerations Criteria for science comparison of Winter Block (LV Target Spec Rev. D) with proposed THEMIS Block –Phase 0/1 dayside diffusion encounters –Phase 0/1 neutral sheet dwell time (FD currently using a proxy) –Phase 2b neutral sheet dwell time (Fairfield-based) –Phase 2d (extended mission) neutral sheet dwell time (Fairfield-based)

April 4, 2014 Flight Dynamics 3 Timeline Comparison March 7 th Launch The following is a J 2 -based estimate of the timeline of events for a Winter Block v. THEMIS Block launch. March 7 th chosen for ease of comparison with slides present by V. Angelopoulos at the Mar 2014 SWT.

April 4, 2014 Flight Dynamics 4 Science Metric Comparison Summary of current post-processed results –All ephemerides listed here are FDOA-produced –Good agreement on the Mar 15 th data with Steve 2 –Phase 0 night for THEMIS Block occurs in late Nov. –Phase 1 night for Winter Block occurs in mid-June –Phase 1 night for THEMIS Block occurs in mid-Dec Steve 2 to provide?

April 4, 2014 Flight Dynamics 5 Flight Dynamics Open Concerns