New Horizons Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) Pluto Encounter Raw Data, Version 1.0

This data set contains Raw data taken by the
New Horizons Pluto Energetic Particle Spectrometer Science Investigation
(PEPSSI) instrument during the KEM1 ENCOUNTER mission phase. These data
were migrated from the PDS3 dataset: NH-P-PEPSSI-2-PLUTO-V3.0.

PEPSSI is a particle telescope and a time-of-flight (TOF) spectrometer that
measures ions and electrons over a broad range of energies and
angles. Particle composition and energy spectra are measured for H to
Fe from ~ 30 keV to ~1 MeV (but not all species are uniquely separated)
and for electrons from ~30 keV to 700 keV. PEPSSI comprises a
time-of-flight (TOF) section and a solid-state detector (SSD) array
that measures particle energy. The combination of measured energy and
TOF provides unique particle identification by mass and particle energy
depending on the range: for protons from ~30 keV to ~1 MeV; for heavy
(CNO) ions from ~80 keV to ~1 MeV. Lower-energy (>3 keV) ion fluxes are
measured by TOF only, but without the SSD signal, providing velocity
spectra at these energies as well. Due to storage and bandwidth
limitations, all event data cannot be stored or telemetered to the
ground. Instead, a round-robin algorithm is used to save Energy, TOF,
and timing data for select events. The common data products contain
these event and summary measurements, accumulated over fixed periods of
86,400 seconds, with each period in a single file comprising multiple
binary tables.

During the Pluto Charon Encounter mission phase starting in
January, 2015, there were several sub-phases: three Approach
sub-phases, (AP1, AP2 and AP3); a CORE sequence for the Pluto
flyby on 14 July, 2015 (Day Of Year 195), sometimes also referred
to as NEP (Near-Encounter Phase); three Departure sub-phases
(DP1, DP2, DP3); a Transition sub-phase ending in late October, 2016,
closing out the Pluto Encounter mission phase. For this final PEPSSI
delivery for the Pluto mission phase, this data set includes the
Approach data plus the CORE and Departure sequences' data, as well as
normal operation and Calibration Campaign data during Transition, and
has all data downlinked through the end of October, 2016.

During the Approach phase, PEPSSI performed functional tests including
a memory refresh, and otherwise operated as normal, turning off and on
around spacecraft trajectory correction maneuvers, and taking data
during a series of plasma rolls, on DOY 107, 115, 121, 128, 148, 156,
and 176. There were two other dedicated SWAP and PEPSSI rolls on DOY
163 and 171. PEPSSI was powered on and collecting data throughout the
encounter time frame.

PEPSSI was generally turned on and taking data for the Departure and
Transition sub-phases, the exceptions being when PEPSSI was turned off
during spacecraft events such as 3-axis operations and trajectory
correction maneuvers.

Due to a spacecraft safing event on 04 July, 2015 (DOY 185), the
balance of the science load from then-executing 15184 sequence
(nominal start time on DOY 184 in 2015) was sacrificed to ensure the
15188 CORE load with the flyby sequence could be loaded onto the
spacecraft and started on time. As a result, there is a gap in the
PEPSSI data from approximately DOY 186 to DOY 188.

Labels were redesigned during migration using the .FIT header and PDS3 .LBL
files, but the data files are unchanged from their PDS3 version.