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PEPSSI 10 keV to 1 MeV particle environment of MU69


 * Example MT from a similar observation at Pluto
 * https://www.spaceops.swri.org/nh/wiki/index.php/MT1.3e-1.2


 * Version
 * 1.0


 * Last Revised
 * [2017-01-02 Matt Hill]


 * Reviewers
 * [INSERT INITIALS HERE]


 * Last Reviewed
 * [INSERT DATE + INITIALS HERE (e.g., 2018-12-31 by JRS)]


 * Time, distance, resolution, or phase constraints
 * OC Outer Core (approach and departure) K-7 to K-1 d; K+1 to K+2
 * IC Near Encounter Phase K-1 to K+1 d


 * General Description
 * Operate PEPSSI in nominal science mode throughout the MU69 encounter at sufficient data rate.


 * Scientific Motivation
 * PEPSSI is sensitive to the plasma, suprathermal, and energetic particles environment and can potentially detect changes in these populations due to their interaction with MU69.


 * Detailed Information
 * Nominal Science. PEPSSI should be operated analogously to at Pluto and similarly to cruise, that is in the NORMAL (not DIAGNOSTIC or boot) mode, with nominal  LV and HV settings as established, typically, by the PEPSSI internal macro # 10 (0xA).  Whenever possible New Horizons should maintain the HGA-to-Earth attitude as it is our nominal attitude at which more measurements have been taken and therefore allowing best comparison with any encounter data.  Having a baseline attitude through the encounter whenever possible will be very helpful for looking for variations arising from the MU69 interaction.  PEPSSI being powered on in nominal science mode as continuously as possible is very important for understanding the measurements.  We desire no power cycles during the encounter.
 * K-7 to K-2 day. PEPSSI should use these data rates (integration intervals) N1,N2,N3,status = 3600,40,7200,300 s. As a shorthand we refer to this as N2 = 40s since the other rates are usually much lower, not contributing significantly to the data volume, and are usually at the same values.
 * K-2d to K+2 day. PEPSSI should use these data rates, N1,N2,N3,status = 3600,1,7200,300 s.
 * Plasma Rolls (during any KBO mission phase). To obtain sufficient angular resolution PEPSSI should be in N2 = 1 s mode during all Plasma Rolls, and should otherwise ride along with the SWAP plasma roll plan. PEPSSI should enter N2 = 1s mode at least 5 minutes before the slew to the role begins and remain in N2=1s mode for at least 5 minutes after the operation ends.  The 5 minute provides a baseline for disentangling the  angular variations from any temporal or spatial variations that could be underway.
 * Flow direction scan. It would be useful to perform a scan similar to the Pluto therm scan (2015-195 approx. 11:50 - 12:05) which at Pluto allowed PEPSSI to detect a plasma deflection as evidenced in the suprathermal ions and could help identify such a flow variation at MU69 as well. If there is not already a scan from another instrument (for which PEPSSI would be a ride along), it should be considered whether a particles & plasma scan should be conducted.
 * N2 resets. As at Pluto, the PEPSSI N2=1s command should be given during each "command clump" to reset N2 to the encounter rate in the event that PEPSSI is powered off during the encounter. If PEPSSI is powered off it would result in PEPSSI's data rate being set to N2 = 40s, far too low for encounter.
 * Data Volume. The N2 = 40 data rate is 4.5 Mbits/day and the N2 = 1 s data rate is 155 Mbits/day.  Note that these data volumes are the interplanetary data volumes used during cruise.  IMPORTANT: At Pluto we estimated the data volumes more conservatively, using Jupiter as the best analogy.  So at Pluto the N2 = 1s data rate estimate was over 200 Mbits/day.  To prevent adding margin on top of margin the current best estimate data volume is used here, but that should be noted by those tracking data volume, so that enough margin is included.  (Explanation for variable data volume estimate:  Since the PEPSSI data are compressed by PEPSSI the data volume is dependent on the type of data being taken.  That is, particle fluxes and composition can result in a different compression rate and therefore a different data volume.)