Document title: Project Data Management Plan (PDMP) for Solar,
Anomalous, and

Magnetospheric Particle Explorer (SAMPEX)

Project: SAMPEX

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SAMPEX_30S_FLUX_CDF

SAMPEX_30S_RATE_ASCII

SAMPEX_POLCAP_FLUX_ASCII

SAMPEX_POLCAP_FLUX_CDF

SAMPEX_POLCAP_RATE_ASCII

EID: PDMP

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1998\.

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\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

GODDARD SPACE FLIGHT CENTER

PROJECT DATA MANAGEMENT PLAN (PDMP)

FOR

SOLAR, ANOMALOUS, AND

MAGNETOSPHERIC PARTICLE EXPLORER

(SAMPEX)

FOREWORD

The National Aeronautics and Space Administration (NASA) has initiated
the Small Explorer (SMEX) Program to launch small and moderate sized
space payloads to provide frequent opportunities for highly focused and
relatively inexpensive space science missions. This program will also
allow training opportunities for the next generation of scientists and
engineers.

Dr. Lennard A. Fisk, then Associate Administrator for NASA\'s Office of
Space Science and Applications (OSSA), announced on April 4, 1989, the
selection of the first series of SMEX to study some of the most
important questions in space physics, astrophysics, and upper atmosphere
science. The Solar Anomalous and Magnetospheric Particle Explorer
(SAMPEX) was one of the selected missions. SAMPEX was launched on July
3, 1992.

Prepared by:
[                                                                                        ]{.underline}
[                       ]{.underline}\
Richard Hollenhorst Date\
SMEX Software Manager

Approved by:
[                                                                                        ]{.underline}
[                       ]{.underline}\
Daniel Baker Date\
SMEX Project Scientist

Approved by:
[                                                                                        ]{.underline}
[                       ]{.underline}\
Glenn Mason Date\
SAMPEX Principal Investigator

Approved by:
[                                                                                        ]{.underline}
[                       \
]{.underline}George Withbroe Date\
Director, Space Physics Division

Approved by:
[                                                                                        ]{.underline}
[                       \
]{.underline}Joseph King Date\
Director, National Space Science Data Center

**TABLE OF CONTENTS**

1.0 PROJECT OVERVIEW 1

1.1 INTRODUCTION 1

1.1.1 Scope 1

1.2 PROJECT DESCRIPTION 1

1.2.1 Project Objectives 1

1.2.2 Project Operations Summary 4

1.2.3 Spacecraft Description 4

1.3 INSTRUMENT OVERVIEW 11

1.3.1 Low Energy Ion Composition Analyzer (LEICA) 13

1.3.2. Heavy Ion Large Telescope (HILT) 14

1.3.3 Mass Spectrometer Telescope (MAST) 15

1.3.4 Proton/Electron Telescope (PET) 16

2.0 PROJECT DATA MANAGEMENT REQUIREMENTS 18

2.1 END-TO-END DATA FLOW 18

2.1.1 Planning and Scheduling 18

2.1.1.1 Planning 18

2.1.2 Operational Data Flow 19

2.1.3 Space Segment 20

2.1.4 Ground Segment 21

2.1.4.1 Data Handling 21

2.1.4.2 Data Archives 23

2.1.4.3 Network 24

2.2 DATA DESCRIPTION 24

2.2.1 LEICA Data Overview 27

2.2.1.1 Raw Data 27

2.2.1.2 Analyzed Science Data 28

2.2.2 HILT Data Overview 29

2.2.2.1 Raw Data 29

2.2.2.2 Analyzed Science Data 30

2.2.3 MAST Data Overview 30

2.2.3.1 Raw Data 30

2.2.3.2 Analyzed Science Data 31

2.2.4 PET Data Overview 31

2.2.4.1 Raw Data 31

2.2.4.2 Analyzed Science Data 31

2.3 DATA ARCHIVING AND ACCESSIBILITY 32

2.3.1 Data and Software Archiving Plan 32

2.3.1.1 Master Data Files 32

2.3.1.2 30-Second Rate and Flux Averages 32

2.3.1.3 Polar Cap Rate and Flux Averages 33

2.3.1.4 Formats 33

2.3.1.5 Caveats 33

2.3.1.6 Period of Archival at the UMSOC 33

2.3.2 Schedule for Data Delivery 35

2.3.3 Data Format Standards 35

2.3.4 Archive Media 36

2.3.5 Data Quality 36

2.3.6 Data Disposition 36

3.0 PDMP IMPLEMENTATION, MAINTENANCE AND MANAGEMENT 36

3.1 ROLES AND RESPONSIBILITIES 36

3.2 CHANGE CONTROL 36

3.3 RELEVANT DOCUMENTATION 37

#   {#section .unnumbered}

# ![](media/image1.wmf){width="6.763888888888889in" height="9.63888888888889in"}

# 1.0 PROJECT OVERVIEW

## 1.1 INTRODUCTION

The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) will
carry out energetic particle studies of outstanding scientific questions
in the fields of space plasma physics, solar physics, heliospheric
physics, cosmic ray physics, and middle atmospheric physics. SAMPEX will
determine the ionization state of the Anomalous Cosmic Ray component in
order to identify the source of these mysterious cosmic rays, and the
method of their energization in astrophysical plasmas. SAMPEX will
provide new information on the composition of the solar atmosphere so
that we may learn more about the origin of our solar system and about
the relation between the material making up the sun with that of the
planets. SAMPEX will make the first detailed survey of relativistic
electrons which plunge from the radiation belts into our atmosphere and
may decisively influence the chemistry of the atmospheric ozone.
Finally, SAMPEX will provide unprecedented detail about the composition
of cosmic rays entering the solar system from outside sources in order
to determine whether cosmic rays originate in supernovae explosions or
in other types of processes in the galaxy. SAMPEX will measure the
particle flux and composition over a substantial portion of the solar
cycle (Figure 1-1).

### 1.1.1 Scope

This document describes the SAMPEX mission Project Data Management Plan
for the SMEX Project. Each SMEX mission will develop its own PDMP.

## 1.2 PROJECT DESCRIPTION

### 1.2.1 Project Objectives

SAMPEX will measure the electron and ion composition of energetic
particle populations from \~0.4 MeV/nucleon to hundreds of MeV/nucleon
from a zenith oriented satellite in near-polar orbit, using a
coordinated set of detectors with excellent charge and mass resolution,
and with much higher sensitivity than previously flown instruments.
While over the Earth\'s magnetic poles, the instruments will study the
composition of anomalous cosmic rays, solar energetic particles, and
galactic cosmic rays. At lower magnetic latitudes, the properties of
Earth\'s magnetic field will allow determination of the ionization state
of three particles at energies much higher than can be studied from
interplanetary spacecraft. At subauroral latitudes, SAMPEX will also
observe precipitating relativistic magnetospheric electrons, which
undergo crucial interactions within the middle atmosphere.

In the energy range below \~ 50 MeV/nucleon, there are at least six
elements (He, C, N, O, Ne, and Ar) whose energy spectra show large
increases in flux above the quite-time galactic cosmic ray spectrum.
This \"anomalous\" cosmic ray (ACR) component is generally believed to
represent neutral interstellar particles that drift into our solar
system (i.e., the heliosphere), become ionized by solar wind
interactions or solar UV radiation, and are than accelerated. This model
makes a unique prediction: the ACR should be singly ionized, (an
assertion for which there is only limited evidence). SAMPEX will make
direct measurements of the ACR charge state by using the Earth\'s
magnetic field as a giant charge-state spectrometer. Indeed, by
organizing the particle fluxes by magnetic cutoff rigidity, SAMPEX
measurements will be able to distinguish amongst a number of possible
charge states for ACR nuclei. If the ACR are indeed singly ionized, then
this component represents a direct sample of the local interstellar
medium.

![](media/image2.wmf){width="5.986111111111111in"
height="3.1666666666666665in"}

Figure 1-1

Solar flares frequently inject large populations of energetic heavy
nuclei into the interplanetary medium. The elemental and isotopic
composition of these particles provide crucial information for
understanding the history of solar system material and to the study of
solar flare acceleration and propagation processes. High sensitivity
spectrometers on SAMPEX will have 1-2 orders of magnitude more
collecting power than previous instruments.

The number of electrons stripped off solar energetic particle (SEP)
nuclei within the sun\'s atmosphere is determined by plasma conditions
at the acceleration site; thus, detailed determinations of the
individual ionic species can be derived, in principle, from the charge
state distribution measured far from the sun. Large solar flares show
ionization states directly related to coronal temperatures, although it
has not been possible to associate the observed distribution with a
single equilibrium temperature. In addition to large solar flares, there
is also a class of small, impulsive solar flares with enormous
enhancements in the 3He/4He ratio (103 - 104) as well are large (\~ 20)
enrichments of heavy nuclei such as Fe.

Observations at geosynchronous orbit have found that relativistic (\>1
MeV) electron intensities can increase by orders of magnitude for
periods of several days. These enhancements are related to the presence
of recurrent high-speed solar wind streams, and show a strong solar
cycle (11-year) dependence. Numerical modeling shows that when these
electrons precipitate they can cause large energy depositions at 40-60
km altitude in the atmosphere, dominating other ionization sources at
these heights.

Precipitating relativistic electrons may lead to substantial long-term
increases in the levels of odd nitrogen compounds (NOx) at these heights
with an attendant impact on local ozone levels via the reactions NO + O3
→ NO2 + O2, and NO2 + O → NO + O2. Thus, relativistic electrons may
provide a mechanism for coupling the 11-year solar activity cycle into
the middle and lower atmosphere. It is therefore a critical problem to
determine the actual intensity and spatial extent of relativistic
electron precipitation, vital information that SAMPEX will provide.

Galactic cosmic rays are a directly accessible sample of matter from
outside the solar system. A spectrometer on SAMPEX will carry out
measurements of the isotopic composition of this sample of high energy
matter, which contains a record of the nuclear history of cosmic rays.
Cosmic ray isotope observations have already revolutionized our thinking
about both cosmic ray origin and propagation. As an example, prior
measurements have shown that 22Ne is more than a factor of 3 times more
abundant in cosmic ray source material than in the solar system. The
abundances of 25Mg, 26 Mg, 29Si, and 30Si are all enhanced by a factor
of \~1.5. The exposure obtained on SAMPEX will make it possible to
extend the search for isotopic differences between galactic and solar
cosmic ray material to many other key elements.

SAMPEX will make measurements over energy, charge-state, and sensitivity
ranges not planned for by any other cosmic ray mission. For example, by
using the magnetic fields available in low-Earth orbit, it complements
the Advanced Composition Explorer (ACE) that will be flown far upstream
of the Earth\'s magnetosphere later in this decade. Moreover, in making
measurements of particles directly penetrating the atmosphere, SAMPEX
allows examination of crucial solar-terrestrial linkages. To achieve
these diverse objectives, SAMPEX is slated for a minimum 3-year mission
lifetime, with the objective of extending the mission to six years or
more.

This broad range of inquiries can only be addressed using experimental
measurements obtained on a low altitude near-polar orbiting spacecraft.
The SAMPEX mission uses a single spacecraft developed by the Small
Explorer (SMEX) Project at NASA/Goddard Space Flight Center. The
spacecraft provides the total support (power, data, thermal, structural,
etc.) to four scientific instruments. The spacecraft is designed as a
single string system. Redundancy is almost non-existent. A system design
has been selected that uses proven design concepts and flight qualified
or readily available hardware wherever possible. A Class C Performance
Assurance (PA) program was implemented for the SAMPEX payload.

Development of the instrument and spacecraft began immediately after the
selection of SAMPEX by the Associate Administrator for Space Science and
Applications in April 1989. The selection of SAMPEX completed the
process begun with the release of NASA\'s Announcement of Opportunity
OSSA 2-88.

### 1.2.2 Project Operations Summary

The SAMPEX spacecraft is operated through the Operations Control Center
located at Goddard Space Flight Center. The mission is operated 24 hours
a day, seven days a week. The data is transmitted to the ground twice
per day through the Wallops Flight Facility. The data is transmitted as
a series of CCSDS transfer frames. Commanding is performed once per day.
Command data is also CCSDS compliant. SAMPEX is the first NASA mission
to fully exercise the CCSDS data system recommendations for packetized
command and telemetry.

### 1.2.3 Spacecraft Description

Due to the weight, power, and cost constraints the SAMPEX spacecraft was
designed as a single string system. It was built in the \"in house\"
mode by Code 700 personnel with support from Codes 300 and 500. The flow
diagram of the data and electrical systems of the spacecraft are shown
in Figure 1-2. The SAMPEX payload underwent a full test and verification
program including an Engineering Test Unit (ETU).

  ---------------------------------------------------- ----------------------------------------------------
  ![](media/image3.wmf){width="3.0965277777777778in"   ![](media/image4.wmf){width="2.8465277777777778in"
  height="4.736111111111111in"}                        height="4.902777777777778in"}

  ---------------------------------------------------- ----------------------------------------------------

Figure 1-2\
Spacecraft Electrical Diagrams

[Structural/Mechanical]{.underline}

The SAMPEX mechanical subsystem supports the SAMPEX instruments and
subsystem components and fit within the Scout small heat shield. The
mechanical system consists of the primary structure, instrument support
structure, isobutane tank, deployable solar arrays, and the yo-yo despin
mechanism. The SAMPEX bus structure contains most of the subsystem
components and provides the interface to the Scout 200-E adapter on the
fourth stage of the Scout launch vehicle. The SAMPEX Spacecraft is shown
in Figure 1-3.

[Power System]{.underline}

The on-orbit average output power of the system is 102 watts using a
Gallium Arsenide solar array with no shadowing and minimum solar
intensity at end of minimum mission life (3 years). During the launch
phase into a full sun orbit, the power system supplied 200 W-HR of
energy. This is based on an 80 percent battery depth of discharge and a
9 A-HR battery.

[Power Distribution/Pyro Control Unit (PD/PCU)]{.underline}

The primary function of the PD/PCU is to provide primary power
distribution and fusing to other spacecraft subsystems, and control and
power to spacecraft\'s separation and deployment pyrotechnic devices.
Primary power from the power subsystem is received over the three power
busses: essential, non-essential, and pyrotechnic. The PD/PCU
distributes the power to the subsystems through appropriate relay and
fuse circuits.

The PD/PCU electronics provides for receipt of power relay commands from
the SEDS, monitoring of relay status, collection of internal
housekeeping data, primary current sensing, and signal conditioning for
the CTT, RPP, ACE, and transponder. The PD/PCU receives commands and
transmits data via the 1773 data bus.

[Small Explorer Data System (SEDS)]{.underline}

The Small Explorer Data System (SEDS) is comprised of a
Recorder/Processor/Packetizer (RPP) and a Command and Telemetry Terminal
(CTT).

SEDS (Figure 1-4) provides on-board computers that can be programmed to
perform mission unique functions as required and provides autonomous
operation of the spacecraft when it is not in contact with the ground.
It controls the spacecraft attitude and provides primary command and
control of experiments and spacecraft subsystems, and interfaces with
the spacecraft communications system.

SEDS collects data from the different subsystems and instruments, stores
the data, processes it, and sends it to the ground using recognized
packet telemetry standards. The data system uses solid-state memory to
record spacecraft telemetry data when the spacecraft is out of contact
with the ground.

  ---------------------------------------------------- ----------------------------------------------------
  ![](media/image5.wmf){width="3.0833333333333335in"   ![](media/image6.wmf){width="3.0555555555555554in"
  height="2.69375in"}                                  height="3.0833333333333335in"}

  ![](media/image7.wmf){width="3.013888888888889in"    ![](media/image8.wmf){width="3.125in"
  height="4.513888888888889in"}                        height="3.7222222222222223in"}
  ---------------------------------------------------- ----------------------------------------------------

Figure 1-3

SAMPEX Spacecraft

[Recorder/Processor/Packetizer (RPP)]{.underline}

The Recorder/Processor/Packetizer (RPP) provides storage for 26.5
Mbytes, packetizes commands and telemetry and is used as a general
purpose processor.

The RPP supports general spacecraft control functions and specific
control functions such as attitude control.

For general spacecraft control, the RPP monitors data to determine the
general status of the spacecraft, instruments and the data system. The
RPP checks critical parameters to determine if limit conditions have
been exceeded. If they have, the RPP executes predefined stored command
sequences. Working in conjunctions with safehold mechanisms, the RPP
periodically performs a variety of self tests and reports its status to
watchdog systems such as attitude control safehold system.

[Command and Telemetry Terminal (CTT)]{.underline}

The Command and Telemetry Terminal (CTT) is a remote terminal that has
been configured to connect the transponder to the rest of the data
system.

The CTT provides:

o uplink command processing

o downlink telemetry encoding

o spacecraft time management

o local telemetry acquisition and command distribution

o system monitoring

The CTT provides processing for commands and telemetry and can acquire
control of the spacecraft if the RPP fails.

CTT supports low rate (\<100 kbps) communication requirements of
instrument; provides telemetry data acquisition; provides command output
distribution; and provides debug interfaces for integration and test
(I&T) support.

CTT provides command interpretation, 1553/1773 depacketization, sensor
read/condition, housekeeping, attitude determination, self diagnostics,
etc.

![](media/image9.wmf){width="4.805555555555555in"
height="6.305555555555555in"}

Figure 1-4\
SEDS Block Diagram

[Attitude Control System]{.underline}

The Attitude Control System (ACS) is designed as a solar
pointed/momentum biased system using the momentum wheel to orient the
experiment viewing axis about the sun vector. The sensor and actuator
complement consists of one Fine Sun Sensor, five Coarse Sun Sensors, and
Magnetometer, three Torque Rods, and one Momentum Wheel. The spacecraft
pitch axis is kept within 5 degrees of sun line at all times. The
spacecraft yaw axis (experiment boresight) should approach the zenith
(local vertical) vector in the polar regions during science operations.
The spacecraft yaw axis is maintained at an angle greater than 45
degrees from spacecraft velocity vector during science operations.
Ground reconstruction of the spacecraft attitude is required to be less
than 2 degrees.

An Attitude Control Electronics (ACE) Box which contains signal
conditioning electronics and an independent analog safehold mode
completes the ACS hardware manifest. SEDS performs closed loop real-time
attitude determination and control processing. Three-axis attitude
determination is provided by comparing the local measured sun vector and
magnetic field vector with an on-board ephemeris model. Digital control
of the spacecraft attitude is completed by sending appropriate command
signals across the spacecraft data bus to the actuators.

[Antenna System]{.underline}

The SAMPEX antenna system is composed of two quadrifilar helices, two
90° hybrid junctions, and a power divider. These omnidirectional
antennas are located on the top of the spacecraft and on the bottom of a
solar panel. The top antenna is a half-turn quadrifilar with a 150°
beamwidth. The bottom antenna is a three-turn quadrifilar with a 210°
beamwidth. (In this context, the beamwidth is defined as that view
sector of a principle plane where the gain meets or exceeds -5 dBi as
required). Each antenna is fed with a 90° hybrid junction to create the
proper phasing between elements. A power divider feeds each hybrid
junction to create the proper phasing between elements. A power divider
feeds each hybrid junction with a single of equal amplitude and phase.
This system is designed to operate over a 2025-2300 MHz frequency range.

[Transponder]{.underline}

An S-Band transponder operating in full duplex mode provides the
reception of uplinked commands, transmission of telemetry data and
support of the Doppler tracking by the designated ground station. The
received uplink is transmitted as Non-Return to Zero (NRZ) bi-phase
modulated synchronously on a 16 Kilohertz (KHz) subcarrier. The command
data rate is 2 kilobits/second (kbps). The telemetry output signal is
modulated on the transmitter to produce the downlink signal. The
transmitter modulation bandwidth is 3 Megahertz (MHz) and its output
power is 5 watts. The S-band transponder interfaces with the S-band
antenna and the SEDS CTT.

[LAUNCH VEHICLE]{.underline}

The standard Scout launch vehicle is a solid-propellant, four-stage
booster system providing an efficient means of boosting a spacecraft on
a planned trajectory.

[LAUNCH SITE]{.underline}

The launch site for the SAMPEX mission was located at the Western Test
Range (WTR) at Vandenberg Air Force Base (VAFB), California. The Scout
support facilities consist of the NASA Spacecraft Laboratory Ordnance
Assembly Building (OAB) and Spin Test Facility (STF).

## 1.3 INSTRUMENT OVERVIEW

The four SAMPEX scientific sensors each address a subset of the required
measurements with enough overlap in energy range and response to allow
intercalibration and partial redundancy.

The four sensors, and the major institutional responsibilities are the
Low Energy Ion Composition Analyzer (LEICA), the Heavy Ion Large
Telescope (HILT), the Mass Spectrometer Telescope (MAST), and the
Proton/Electron Telescope, (PET). LEICA is being provided by the
University of Maryland, HILT by the Max-Planck-Institut fur
Exterrestrische Physik, MAST/PET by Caltech and GSFC Codes 660/690, and
the DPU by the Aerospace Corporation.

As shown in figure 1-5, the four sensors are serviced by a common Data
Processing Unit (DPU), provided by the Aerospace Corporation. The DPU
has the single data interface with the Small Explorer Data System
(SEDS). Spacecraft housekeeping data is sampled through a 1773B fiber
optic data bus. A one Hertz timing pulse is sent to the Attitude Control
Electronics (ACE) box and the DPU, providing a fiducial from which the
exact timing of each second is obtained.

The measurements made by these four instruments for electrons, and for
typical ion species are summarized in the Table 1-1. The basic
techniques used are time-of-flight vs. energy (LEICA), or dE/dx versus
residual energy (HILT, MAST/PET).

More detailed descriptions of the SAMPEX mission, the four sensors, and
the DPU may be found in a series of six articles in the May/June 1993
issue of IEEE Transactions on Geoscience and Remote Sensing (Vol. 31,
No. 3).

![](media/image10.wmf){width="6.44375in" height="4.736111111111111in"}

Figure 1-5\
Instruments and Major Subsystems

### 1.3.1 Low Energy Ion Composition Analyzer (LEICA)

LEICA is provided by the University of Maryland. LEICA measures
elemental and isotopic abundances over the range from about 0.35 to 10
MeV/nucleon. The instrument is a time-of-flight mass spectrometer that
identifies incident ion mass M and energy by simultaneously measuring
the time-of-flight and residual kinetic energy E of particles that enter
the telescope and stop in one of the array of four Si solid state
detectors. Figure 1-6 shows the basic construction of the LEICA
instrument.

[Low Energy Ion Composition Analyzer (LEICA)]{.underline}

![](media/image11.wmf){width="4.708333333333333in"
height="5.222222222222222in"}

Figure 1-6\
LEICA Instrument Diagram

### 1.3.2. Heavy Ion Large Telescope (HILT)

HILT is provided by the Max-Planck-Institut fur Extraterrestrische
Physik and Aerospace Corporation. The HILT sensor is a large geometry
factor (50 cm2 sr) instrument designed to measure anomalous cosmic rays
near the intensity maximum of their spectrum. This will allow
statistically accurate heavy nuclei spectral and cutoff measurements
required for determination of the ACR charge state, as well as the
charge states of solar energetic particles. HILT determines particle
type by the dE/dx vs. E method; particle trajectory angle is also
determined allowing magnetic cutoff rigidity determination to be done by
ground-based computers. Figure 1-7 shows the construction and major
detector parts of HILT.

[Heavy Ion Large Telescope (HILT)]{.underline}

![](media/image12.wmf){width="5.19375in" height="5.666666666666667in"}

Figure 1-7\
HILT Diagram

### 1.3.3 Mass Spectrometer Telescope (MAST)

MAST is provided by the California Institute of Technology, and Goddard
Space Flight Center. MAST measures the isotopic composition of elements
from Li to Ni in the range from \~ 10 MeV/nucleon to several hundred
MeV/nucleon. MAST consists of a combination of surface barrier and
lithium-drifted solid-state detectors. The first four detectors are
one-dimensional position-sensitive detectors that accurately determine
particle trajectories in order to permit corrections for path length and
detector non-uniformities. Isotope identification is accomplished by the
standard dE/dx vs. E technique and a resolution of sm \~ 0.3 amu will be
achieved, sufficient to resolve isotopes with abundance differences of
\~ 100:1. The MAST detector layout is shown in figure 1-8.

[Mass Spectrometer Telescope (MAST)]{.underline}

![](media/image13.wmf){width="5.166666666666667in"
height="5.416666666666667in"}

Figure 1-8\
MAST Diagram

### 1.3.4 Proton/Electron Telescope (PET)

PET, the Proton/Electron Telescope, is provided by the California
Institute of Technology and Goddard Space Flight Center. The PET system
is an all-solid state detector telescope to allow the measurement of
electron spectra from \~ 1-30 MeV and H and He spectra from \~20 to
several hundred MeV/nucleon. As shown in Figure 1-9, PET has a field of
view of 58°.

[Proton/Electron Telescope (PET)]{.underline}

![](media/image14.wmf){width="3.5in" height="5.138888888888889in"}

Figure 1-9\
PET Diagram

Table 1-1.

SAMPEX SCIENTIFIC INSTRUMENTS

+-------------+-------------+-------------+-------------+-------------+
|             | [LEICA]{    | [HILT]{     | [MAST]{     | [PET]{      |
|             | .underline} | .underline} | .underline} | .underline} |
+-------------+-------------+-------------+-------------+-------------+
| Energy      | \--         | \--         | \--         | 1-30 MeV    |
| range for:  |             |             |             |             |
|             |             |             |             |             |
| electrons\* |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| H\*         | 0.75-8      | \--         |             | 18-250 MeV  |
+-------------+-------------+-------------+-------------+-------------+
| He\*        | 0.4-8       | 3.9-90      | 7-15        | 18-350      |
|             |             |             |             | Mev/nuc     |
+-------------+-------------+-------------+-------------+-------------+
| C\*         | 0.35-12     | 7.2-160     | 12-140      |             |
+-------------+-------------+-------------+-------------+-------------+
| Si\*        | 0.26-18     | 9.6-177     | 19-345      | 54-195      |
|             |             |             |             | MeV/nuc     |
+-------------+-------------+-------------+-------------+-------------+
| Fe\*        | 0.16-25     | 11.0-90     | 24-470      |             |
+-------------+-------------+-------------+-------------+-------------+
| Charge      | 1-28        | 2-28        | 2-28        | 1-28        |
| range for   |             |             |             |             |
| elements\*  |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Charge      | 2-16        | 2           | 2-28        | 1-2         |
| range for   |             |             |             |             |
| isotopes\*  |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Geometry    | 1.0         | 50          | 7-14        | 0.3-1.6     |
| factor      |             |             |             |             |
|             |             |             |             |             |
| (cm2 sr)\*  |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Field of    | 24 x 20     | 90 x 90     | 101         | 58          |
| View (deg   |             |             |             |             |
| full angle) |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Mass (kg)   | 7.4         | 22.7        | 8.8         | (incl. with |
|             |             |             |             |             |
|             |             |             |             | MAST)       |
+-------------+-------------+-------------+-------------+-------------+
| Power (W)   | 4.9         | 7.0         | 5.3         | (incl. with |
|             |             |             |             |             |
|             |             |             |             | MAST)       |
+-------------+-------------+-------------+-------------+-------------+
| Telemetry   | 1.3         | 0.9         | 1.3         | 0.4         |
| (kbps)      |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

\*-Controlled, Level 1 requirement.

Total experiment mass: 38.9 kg (scientific sensors)

[4.0]{.underline} kg (DPU + LVPS)

Subtotal: 42.96 kg

Total experiment power: 17.2 W (from above) + 5.3 W (DPU) = 22.5 W

Isobutane Tank and 3 year gas supply for HILT sensor: 9.33 kg

# 2.0 PROJECT DATA MANAGEMENT REQUIREMENTS

## 2.1 END-TO-END DATA FLOW

### 2.1.1 Planning and Scheduling

Spacecraft planning and scheduling refer to the determination of
spacecraft operations and the coordination of ground system elements to
ensure successful science data collection. Science operations for the
SAMPEX mission can be described as routine (as opposed to missions which
have a campaign or an interactive style of operations). There is no
daily interaction planned between instrument representatives and the
spacecraft, and instrument command functions for routine operations will
be performed by the onboard Data Processing Unit (DPU). The DPU is
responsible for overall control of the science payload and controls the
data acquisition from each instrument and packetizes science data for
recording by the Small Explorer Data System (SEDS).

#### 2.1.1.1 Planning

The scheduling of instrument observations is performed autonomously by
the spacecraft. Routine instrument operations are performed by the
onboard DPU. No additional instrument command activity occurs on a daily
basis. HILT and LEICA in-flight calibrations are performed on a monthly
basis. All other requests for instrument activities to be performed are
on a special request basis. Requests for special operations originate
from the instrument representatives and are transmitted to the Flight
Operations Team (FOT) using the University of Maryland Science
Operations Center (UMSOC) as intermediary. The UMSOC is the primary
point of contact between the FOT and the experimenters; however, the
UMSOC may instruct the FOT to accept requests for instrument commands
directly from designated members of the individual instrument teams.
Requests for special operations are transmitted to the FOT by means of
the Space Physics Analysis Network (SPAN) or by means of fax
transmission.

Science data are recorded onboard the spacecraft in the SEDS. The
precise details of the data sampling and recording scheme is described
in section 2.1.3, the Space Segment. With respect to planning and
scheduling operations it is important to note that:

a\. Science partition playbacks may only be done when the RPP is in
normal mode and the downlink data rate is 900 Kbps.

b\. The science partition is sized to nominally fill up every 12 hours.

The data are played back twice per day at the Wallops Island Orbital
Tracking Station. Playback data quality statistics from ground system
elements are compared against spacecraft telemetry to verify the quality
of the downlink. Should the recorder dump quality be unacceptably low a
Wallops support on the following orbit will be scheduled. Next-orbit
playback opportunities occur approximately 40% of the time. If the
science partition is not successfully dumped at Wallops on the primary
or next-orbit opportunity, the partition will not be released.
Additional science data will be recorded and playback will be attempted
again at the next Wallops acquisition, approximately 12 hours later.
Since only about one third of the science partition is filled during
quiet periods, science return is maximized by not releasing the science
partition. After October 1993, the DSN provides a secondary backup
capability for science recorder operations.

### 2.1.2 Operational Data Flow

This section provides a high level definition of the flow of data from
the instrument package to the University of Maryland Science Operation
Center (UMSOC), the primary science data distribution center for SAMPEX.
Figure 2-1 illustrates the operational data flow of the SAMPEX mission.
The SAMPEX data transmission system includes a space segment and a
ground segment.

![](media/image15.wmf){width="6.722222222222222in"
height="4.930555555555555in"}

Figure 2-1\
Operational Data Flow

The science payload is controlled by the Data Processing Unit (DPU). The
DPU collects and packetizes science data for delivery to the spacecraft.
The DPU routes appropriate data to the Small Explorer Data System (SEDS)
for recording. A solid state recorder dump occurs twice per day at the
Wallops Flight Facility (WFF). WFF transfers the data stream to the
Goddard Space Flight Center (GSFC). The Packet Processor (PACOR)
interfaces with the ground station via NASCOM, and records all incoming
data. All data transfers to PACOR occur during real-time contacts with
the spacecraft or by playback from the ground station.

PACOR performs level zero processing on the incoming telemetry, and
extracts the science data. PACOR transmits the science data sets to the
UMSOC in 24 hour blocks. The UMSOC is responsible for routing the
science data to the various science investigators. UMSOC establishes the
timeline for distribution of instrument specific data sets.

### 2.1.3 Space Segment

The SAMPEX spacecraft was placed by the SCOUT launch vehicle into an 82
degrees inclined, polar, elliptical orbit on July 3, 1992. The final
spacecraft orbit was 512 x 685 km. This orbit is not sun-synchronous.
The minimum anticipated mission duration is 3 years with a strong
objective of achieving a six year mission. With the successful launch,
the payload has a better than 98.5% probability of achieving 9 years in
orbit. Table 2-1 describes various SAMPEX tracking and data acquisition
parameters.

The space segment transports data from the instruments, through on-board
data processing and communication systems, and through transmission to
the ground. The spacecraft subsystems involved in the space segment data
flow are the instruments, DPU, SEDS, and the transponder. The DPU
collects data from the instrument package and transfers it to the SEDS
for recording.

Table 2-1

+-----------------------------------+-----------------------------------+
| Orbital Parameters                | Apogee: 685 Km                    |
|                                   |                                   |
|                                   | Perigee: 512                      |
|                                   |                                   |
|                                   | Inclination: 82°                  |
+-----------------------------------+-----------------------------------+
| Data Rate                         | Peak: Playback + R/T = 900 Kbps   |
|                                   |                                   |
|                                   | Average: R/T = 16 Kbps            |
+-----------------------------------+-----------------------------------+
| Contact Frequency & Duration      | 4 contacts/day                    |
|                                   |                                   |
|                                   | 8-14 min/contact                  |
|                                   |                                   |
|                                   | Orbital Fraction: 2.7%            |
+-----------------------------------+-----------------------------------+
| Contact Period Constraints        | Limited by orbital period (ground |
|                                   | station visibilities)             |
+-----------------------------------+-----------------------------------+

### 2.1.4 Ground Segment

The SAMPEX ground segment elements directly involved in the transmission
and processing of science data are the ground stations, the POCC, PACOR
and the UMSOC. Spacecraft telemetry data are downlinked to the receiving
ground station, where the data are transferred via NASCOM to the POCC
and PACOR. A high level diagram of the relationships and interfaces
between these ground segment elements can be seen in Figure 2-2.

#### 2.1.4.1 Data Handling

a\) [Level Zero Processing]{.underline}. The following list outlines the
Level Zero Processing (LZP) and functions performed by PACOR:

\- Data capture

\- Transfer frame extraction from NASCOM blocks

\- Checking of cyclical redundancy code (CRC)

\- Separation of virtual channels, packet extraction and reassembly

\- Logging of received playback transfer frames to magnetic media

\- Grouping and time ordering of data sets by APID for users

\- Deletion of redundant data (optional)

\- Quality and accounting data generation

\- Store and forward prepared data sets to users via electronic transfer

b\) [Data Quality Checks]{.underline}. Data transmission quality checks
are performed during real-time and playback transmissions from WPS to
the POCC and PACOR by each participating node. At a minimum, the
transmission checks include the processing and data quality checks shown
in Table 2-2.

Telemetry data are monitored as received to detect any data
loss/problems. The POCC, PACOR and WPS uses voice nets to coordinate
data quality and accounting information.

PACOR provides quality accounting information to UMSOC for the level
zero processed data. The message trailer for each data set transmitted
to UMSOC from PACOR includes a quality and accounting capsule (QAC)
containing information on each packet in the data set for which an error
was detected. The entry will identify the packet and error detected,
such as:

\- Application process ID incorrect

\- Packet length code incorrect

\- Mission ID incorrect

\- Source sequence count discontinuity/error

\- Detect frame errors during this packet

UMSOC provides PACOR with reports on transmission status and quality of
data:

\- A weekly summary of quality and quantity of data.

\- UMSOC will provide timely response on suspected anomalous
transmissions.

![](media/image16.wmf){width="5.375in" height="7.402777777777778in"}

Figure 2-2\
SAMPEX Ground Segment

If the data quality is determined to be inadequate, retransmission
occurs:

\- During real-time, PACOR provides data quality information to the FOT
(in the POCC) in time to re-dump the spacecraft recorder if necessary.

\- If the data recorded at the ground station are adequate, a post pass
playback will be scheduled.

\- For data transmitted from PACOR to the UMSOC:

UMSOC can request data retransmission via phone call or FAX request

For data ≤ 30 days old, retransmission will occur within 4-8 hours of
the request.

For data \> 30 days old, retransmission will occur within 3 working days
of the request.

c\) [Physical Data Handling.]{.underline} Data are transmitted via
electronic links between the ground station and the POCC, the ground
station and PACOR, and PACOR and the UMSOC. The data are stored on
analog tapes at the ground station and on optical disk (short term) and
magnetic tape (long term) by PACOR. UMSOC distributes the science data
on rewritable magneto-optical disks to all the co-investigators (Langley
Research Center, Max Planck Institute, Caltech, Aerospace Corp. and
Goddard Space Flight Center).

Table 2-2.

Quality Checks Performed at Various Ground System Elements

  -------------------------------------- ---------- ---------- ----------
  Data Quality Check                     WPS        POCC       PACOR

  Total \# of NASCOM blocks              X          X          X
  sent/received                                                

  Total \# of valid NASCOM blocks                   X          X
  received                                                     

  Total \# of command echo blocks        X          X          
  sent/received                                                

  Total \# of non-telemetry blocks       X          X          
  sent/received                                                

  Total \# of CRC error blocks                      X          X

  Total \# of sequential error blocks               X          X

  Total \# of telemetry transfer frames  X          X          X
  received                                                     

  Total \# of valid telemetry transfer   X          X          X
  frames received                                              

  Total \# of valid telemetry transfer   X          X          X
  frames received for each virtual                             
  channel                                                      

  Total \# of CRC error frames for each             X          X
  virtual channel                                              

  Total \# of sequential error frames               X          X
  for each virtual channel                                     
  -------------------------------------- ---------- ---------- ----------

#### 2.1.4.2 Data Archives

Table 2-3 provides information regarding data archival parameters.

#### 2.1.4.3 Network

a\) [Sites]{.underline}. SAMPEX is supported by the Wallops Island
Orbital Tracking Station and the Deep Space Network (Madrid and Canberra
ground stations). Wallops facilitates recorder dumps, spacecraft
housekeeping data and attitude data twice per day. The DSN sites
accommodate only the spacecraft housekeeping and attitude data.
Spacecraft data from these sites are forwarded to the POCC and PACOR in
parallel via NASCOM.

b\) [Data Types]{.underline} SAMPEX science and housekeeping data are
downlinked as raw telemetry data in CCSDS format and transmitted to the
POCC and PACOR in NASCOM blocks.

c\) [Required Capacity]{.underline}. WPS supports science data recorder
dumps, and receives the 4K, 16K and 900 Kbps downlink telemetry rate.
The DSN sites only receive the 4K and 16 Kbps downlink telemetry rate.
The DSN anticipates station upgraded in October 1993, which will allow
for the 900 Kbps telemetry rate. Note: Downlink rates stated are for
spacecraft data prior to Bi-phase and Viterbi encoding.

The data are transmitted from the ground station to the POCC and PACOR
on a 1.544 Mbps NASCOM T-1 link. Level Zero processed data are
transmitted from PACOR to the UMSOC on a 56 Kbps NASCOM DDCS X.25 link

d\) [Standards and Protocol]{.underline}. All SAMPEX data will be in
CCSDS format. Data are transmitted from the ground station to the POCC
and PACOR in NASCOM blocks. Data are transmitted from PACOR to the UMSOC
in NASCOM DDCS X.25 protocol.

Table 2-3

Data Archival Parameters

+---------+--------------+--------------+--------------+-------------+
| [       | [Data        | [Data        | Storage      | [Storage    |
| Locatio | Type]        | Volume]{.    |              | Media]{     |
| n]{.und | {.underline} | underline}\* | [Duration]   | .underline} |
| erline} |              |              | {.underline} |             |
+---------+--------------+--------------+--------------+-------------+
| WPS     | Raw Data     | 21           | 72 hours     | Analog Tape |
|         |              | Mb           |              |             |
|         | (NASCOM      | ytes/contact |              |             |
|         | blocks)      |              |              |             |
|         |              | \~ 2         |              |             |
|         |              | contacts/day |              |             |
+---------+--------------+--------------+--------------+-------------+
| PACOR   | Raw Data     | 44           | 30 days - on | Optical     |
|         |              | Mbytes/day   | site         | disk and    |
|         | (NASCOM      |              |              | magnetic    |
|         | blocks)      | 16.1         | 2 years -    | tape        |
|         |              | Gbytes/year  | off site     |             |
+---------+--------------+--------------+--------------+-------------+
|         | LZP Data     | 42           | 10 days - on |             |
|         |              | Mbytes/day   | site         |             |
|         |              |              |              |             |
|         |              | 15.3         |              |             |
|         |              | Gbytes/year  |              |             |
+---------+--------------+--------------+--------------+-------------+

\* Does not include fill data or NASCOM overhead

## 2.2 DATA DESCRIPTION

The Instrument Data Processing Unit reads data from each of the four
instruments, performs a selection algorithm on the sensor data, and
forwards the approved data to the SEDS for storage. The selection
algorithm provides efficient use of the solid-state memory aboard the
spacecraft. The instruments can generate very high, event-driven data
rates and the spacecraft can record only a small interval of data at the
highest rates. The algorithms apportion the available data storage on a
periodic basis and prevent the spacecraft recorder from filling up the
full day\'s allocation of memory due to a unusually intense burst of
radiation. Data storage allocation is based on a bytes per orbit
allocation, where an orbit is loosely defined as 90 minutes. There are a
total of 6 orbit-based memory quotas decremented when the associated
data packet is output to the SEDS. Independent memory quotas are
maintained for each of the four instrument\'s event packets, as well as
the HILT and PET high resolution rate packets.

The DPU also generates orbital history data, which are comprised of 48
or 96 second averages of the selected counting rates and housekeeping
parameters over the latest 96 minutes. These history data are downlinked
in VC0 during each acquisition and serve as a quick check of instrument
health and particle intensities over the latest orbit. Instrument
housekeeping data are collected by the DPU. The data are packaged in the
subcommed science packets and in the DPU housekeeping packets.

The SAMPEX spacecraft and instruments generate a variety of housekeeping
telemetry and ancillary data, including voltage monitors, current
monitors, thermistors, relay statuses, mode indications, and various
counters. There is detailed information covering the behavior of the
flight data system and software. The Attitude Control System also
generates a large quantity of telemetry, including attitude quaternions,
orbit propagator results, intermediate ACS algorithm results, actuator
commands and ACS sensor data. The exact content of each SAMPEX packet
can be found in the SAMPEX Telemetry and Command Handbook
(GSFC-S-740-90-968). Additional information is contained in various
subsystem telemetry and command descriptions and users\' guides,
including the SEDS Flight Software Users\' Guide, the Telemetry Packet
Description for the SAMPEX Data Processing Unit, the DPU and Sensor
Command Description. The Instrument processing schemes and algorithms
are presented in the Data Handling Strategy for the SAMPEX DPU.

Table 2-4 defines the packets generated by SAMPEX, with the packets to
be delivered to the UMSOC identified by shading. The UMSOC ingests the
level 0 data from PACOR via an X.25 network link. The incoming data are
stored by a Vaxstation 3100, Model 72 onto a 426 Megabyte Winchester
disk drive and later archived (for the duration of the mission) onto 600
Megabyte rewritable optical disks. Level 1 processing is performed by
the University of Maryland to produce Master Data Files (MDF), which
includes all the level 0 data plus calculated ephemeris and magnetic
parameters. The Master Data Files are formatted using the \"Tennis
Standard\" adopted by the SAMPEX Science Team. At approximately 10 day
intervals, the UMSOC mails rewritable optical disks containing
accumulated MDFs to the co-investigators and to the NSSDC. The UMSOC
includes an additional Vaxstation 4000, Model 60, which is primarily
used for Level 1 processing, the generation of standard rate plots, and
the production of MDF copies, and a third Vaxstation 4000, Model 90,
which is primarily used for LEICA science analysis (Figure 2-3). Access
is provided via 8 terminal ports, and network logins. Bulk I/O devices
include a streamer tape drive, a CD-ROM optical disk reader, two single
rewritable optical disk drives, two rewritable optical disk jukeboxes
(16 disk capacity) with single drives, an 8mm tape drive, and magnetic
disks.

Table 2-4\
SAMPEX Packet List

  ------ ----- ------ ----------------------- ------ ----- ------ ----------------------
  APID   VC    Size   Description             APID   VC    Size   Description

  1      0,1   304    SEDS FSW Mode           22     0,1   50     ACE Safehold Status
                      Independent Status Data                     

  2      0,1   784    Normal Mode Status      23     0,1   54     ACE Diagnostic Command
                      Packet                                      Response

  3      0,1   528    Launch Mode Status      24     0,1   50     ACE Raw Sensor Data
                      Packet                                      

  4      0     80     Real-time Significant   26     0,1   160    ACS Contamination &
                      Event Packet                                Calibration Matrices

  5      0     80     Playback Significant    30     0     144    CTT Memory Dwell
                      Event Message Packet                        Packet

  6      0     228    RPP Table Dump Packet   31     0     144    RPP Memory Dwell
                                                                  Packet

  7      0     228    RPP Memory Dump Packet  32     0,1   72     SEDS Data Type
                                                                  Diagnostic Packet

  8      0     228    CTT Table Dump Packet   33     0     500    HILT History Packet

  9      0     228    CTT Memory Dump Packet  34     0     500    LEICA History Packet

  10     0,1   18     ACS Mode Status Message 35     0     512    MAST History Packet

  11     0,1   42     ACS Attitude            36     0     506    PET History Packet
                      Determination                               

  12     0,1   100    ACS Command Status      37     0     380    DPU History Packet
                      Message                                     

  13     0,1   132    ACS Orbit Data          38     0     96     Real Time DPU
                                                                  Housekeeping

  14     0,1   224    ACS Statistics          39     0     122    Real Time Status
                      Diagnostics                                 

  15     0,1   528    ACS Attitude            40     0     30     Real Time Command
                      Diagnostics                                 Error Echo

  16     0,1   184    ACS Control Diagnostics 41     0     20     Real Time DPU State
                                                                  Change

  17     0,1   320    ACS Configuration       42     2     var.   Subcommed Instrument
                      Diagnostics                                 Data

  18     0,1   150    CTT I/O Card            43     0     278    EEPROM/LCA Memory Dump

  19     0,1   66     PD/PCU Analog and Relay 44     0     276    DPU memory Dump
                      Status                                      

  20     0,1   86     PSE Analog and Bilevel  45     0     60     DPU Parameter Dump
                      Telemetry Status                            

  21     0,1   60     ACE Housekeeping Data                       
  ------ ----- ------ ----------------------- ------ ----- ------ ----------------------

Note: Shaded packets are delivered to the UMSOC.

![](media/image17.wmf){width="5.319444444444445in"
height="6.596527777777778in"}

FIGURE 2-3

University of Maryland Science Operations Center

### 2.2.1 LEICA Data Overview

#### 2.2.1.1 Raw Data

The Low Energy Ion Composition Spectrometer (LEICA) returns data of four
types: rate data, event data, housekeeping data, and status data.

RATE DATA consist of counts of various LEICA detectors or combination of
detectors accumulated over 6-second periods. The 12 LEICA counting rates
are listed in Table\
2-5.

The LEICA EVENTS return detailed information on a single ion including
time-of-flight, energy signal, SSD ID, priority ID, and directional
information. Since in general only a sample of detailed events can be
accommodated by the telemetry, the instrument uses the priority ID to
ensure a reasonable representation of light and heavy nuclei.

LEICA HOUSEKEEPING DATA include information on temperatures, low and
high voltage monitors. The LEICA STATUS DATA include enable/disable
information on the detectors and the high voltage and values specifying
the slope of the slant discriminator. LEICA history data include a
selection of rates and housekeeping values for use in quickly
determining instrument health and general particle environment.

Table 2-5\
LEICA Rate Data

  ---------------- ------------- ----------------- ------------------------
  Rate Acronym     Type          Response          Energy Range

  D1               Single        All ions &        \>800 keV (P); \>600 (e)
                                 electrons         

  D2               Single        All ions &        \>800 keV (P); \>600 (e)
                                 electrons         

  D3               Single        All ions &        \>800 keV (P); \>600 (e)
                                 electrons         

  D4               Single        All ions &        \>800 keV (P); \>600 (e)
                                 electrons         

  START            Single        All ions &        \>250 keV(P);\>30 keV(e)
                                 electrons         

  STOP             Single        All ions &        \>250 keV(P);\>30 keV(e)
                                 electrons         

  DCR              Coincidence   All ions          \>250 keV (P)

  TCR              Coincidence   All ions          0.8-6.0 MeV (P)

  Hi Priority      Coincidence   Z\>2 ions         0.49-8.3 MeV/nuc

  Lo Priority      Coincidence   He                0.5-6.6 MeV/nuc

  Protons          Coincidence   H                 0.8-6 MeV

  IFC Counter      Not a                           
                   particle rate                   
  ---------------- ------------- ----------------- ------------------------

#### 2.2.1.2 Analyzed Science Data

LEICA is designed to measure the elemental abundances, energy spectra,
and direction of incidence of ions from helium to iron in the
approximate energy range 0.5 - 10 MeV/nucleon. The information from the
LEICA Event Data determines the charge, kinetic energy, and direction of
arrival of each analyzed event. Fluxes as a function of species, energy,
and time are constructed by combining the Event Data with the Lo and Hi
Priority normalizing rates. Solar energetic particles, anomalous cosmic
rays, and magnetospheric particles are separated using their temporal
and spatial variations.

### 2.2.2 HILT Data Overview

#### 2.2.2.1 Raw Data

The Heavy Ion Large Telescope (HILT) returns four types of data: rate
data, pulse-height event data, housekeeping data, and status data. The
time resolution and characteristics of HILT rate data are summarized in
Table 2-6.

The EVENT data provide the response of all sensor elements to individual
ions. The 12 parameters measured for each event allow the determination
of the ion\'s energy, nuclear charge, atomic mass (for light ions), and
direction of incidence. The HILT event selection logic defines a total
of 4 event types, corresponding to four coincidence rates (see Table
2-6). The maximum number of events per second of every event type can be
defined by ground command, and the total number of HILT events per orbit
is determined by the memory allocation algorithms of the DPU. This
allows the optimization of the operation of the instrument under various
conditions, e.g., in the magnetosphere and during solar flares.

Table 2-6\
HILT Rate Data

+--------+--------------+-------------+----------+------------+------+
| Rate   | Time         | Rate Type   | Ion      | > Energy   |      |
| A      | R            |             |          | > Range    |      |
| cronym | esolution(s) |             |          | > (Me      |      |
|        |              |             |          | V/nucleon) |      |
+--------+--------------+-------------+----------+------------+------+
| HE1    | 6            | Coincidence | He       | 4.3 - 9.0  |      |
+--------+--------------+-------------+----------+------------+------+
| HE2    | 6            | Coincidence | He       | 9.0 - 38   |      |
+--------+--------------+-------------+----------+------------+------+
| HZ1    | 6            | Coincidence | Z\>2     | 8.2 - 42   |      |
+--------+--------------+-------------+----------+------------+------+
| HZ2    | 6            | Coincidence | Z\>2     | 42.0 - 220 |      |
+--------+--------------+-------------+----------+------------+------+
| SSD1   | 24           | Single      | All ions | \>5        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| SSD2   | 24           | Single      | All ions | \>5        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| SSD3   | 24           | Single      | All ions | \>5        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| SSD4   | 24           | Single      | All ions | \>5        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| PCFE   | 48           | Single      | All ions | 2.5 - 8    | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| PCRE   | 48           | Single      | All ions | 2.5 - 8    | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| IK     | 48           | Single      | Z≥2      | 3.0 - 9    | (He) |
+--------+--------------+-------------+----------+------------+------+
| CsI    | 48           | Single      | All ions | \>22       | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| HSS1   | 0.1          | Single      | All ions | \>4        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| HSS2   | 0.1          | Single      | All ions | \>4        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| HSS3   | 0.1          | Single      | All ions | \>4        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| HSS4   | 0.1          | Single      | All ions | \>4        | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| HPCRE  | 0.1          | Single      | All ions | 2.5 - 21   | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+
| HIK    | 0.1          | Single      | All ions | 2.5 - 7    | \    |
|        |              |             |          |            | (P\) |
+--------+--------------+-------------+----------+------------+------+

The DPU generates HOUSEKEEPING DATA of a number of HILT voltages and
temperatures and thus provides a continuous record on health and safety
of the experiment. A detailed description of all parameters monitored
may be found in the Telemetry Packet Description for the SAMPEX Data
Processing Unit (DPU). The HILT STATUS DATA include information on the
status of the HILT High Voltage, HILT Valve and Cover Motors, in-flight
calibration, solid state detectors, and HILT EEPROM Memory and XILINX.

#### 2.2.2.2 Analyzed Science Data

HILT is designed to measure heavy ion elemental abundances, energy
spectra, and direction of incidence in the mass range from helium to
iron and in the energy range 4 to 220 MeV/nucleon. From the pulse
heights in the HILT Event Data it is possible to determine the nuclear
charge (Z), the kinetic energy, and the direction of arrival of each
analyzed event. The Event Data are combined with the Rate Date to
produce fluxes of the various species over the instrument energy
interval as a function of time. Distinctive spatial and temporal
variations will permit the separate identification of particle
populations of magnetospheric, solar, galactic, and interplanetary
origin.

### 2.2.3 MAST Data Overview

#### 2.2.3.1 Raw Data

The Mass Spectrometer Telescope (MAST) consists of a telescope composed
of 11 silicon solid state detectors, including four position sensitive
devices, and its associated electronics. There are several categories of
raw data from MAST, as summarized below.

RATE DATA consist of scaled counting rates of various MAST signals,
including coincidence rates involving various detector combinations,
discriminator rates, and an instrument live time scaler. Some rates,
best described as \"engineering data\", include individual detector
count rates, while others provide \"physics\" measurements of the fluxes
of interplanetary H, He, and Z\>2 nuclei in several different energy
ranges. All 75 rates are accumulated over a period of 6 seconds. Because
some rates are subcommutated, it takes 96 seconds to sample them all.
STATUS DATA, giving the status of the MAST internal calibrator, are
contained in one byte appended to the Rate Data. The MAST History Packet
includes 192 second samples of 38 of these rates as

well as Housekeeping Data.

EVENT DATA consist mainly of energy loss measurements for individual
nuclei that are analyzed by the instrument. The 184 bit format includes
fourteen 12-bit pulse heights from detectors M1 to M4 and D1 to D6. The
remainder of the Event Data is devoted to bits describing the event type
(H, He, Z\>2, etc.), \'range\' in the telescope (last detector
triggered), and various discriminators. Because the actual event rate in
MAST is sometimes many thousand per second, only a prioritized sample of
events is transmitted to the ground.

HOUSEKEEPING DATA include values for four thermistors located at various
points within the MAST telescope and electronics.

#### 2.2.3.2 Analyzed Science Data

MAST is designed to measure the elemental and isotopic composition of
energetic nuclei from He to Ni (Z = 2 to 28). From the pulse heights in
the MAST Event Data it is possible to determine the nuclear charge (Z),
the mass (M), and the kinetic energy of each analyzed event. These data
will be used to measure the composition of energetic nuclei from
galactic, solar, and magnetospheric sources in the energy range from
\~15 to 200 MeV/nuc. With the MAST Rate Data, the time history of
various species will be plotted, thereby aiding in the identification of
solar events and trapped particle populations. The Rate Data are also
necessary to normalize the analyzed event data to obtain differential
energy spectra.

### 2.2.4 PET Data Overview

#### 2.2.4.1 Raw Data

The Proton-Electron Telescope (PET) consists of a telescope composed of
8 silicon solid state detectors and its associated electronics. The
categories of raw data obtained from PET are listed below.

RATE DATA consist of scaled counting rates of various PET signals,
including coincidence rates involving various detector combinations,
discriminator count rates, and an instrument live time scaler. Some rate
provide \'engineering data\' such as individual detector count rates,
while others provide \'physics\' measurements of the fluxes of energetic
electrons, protons, and heavier nuclei in several different energy
ranges. The 32 PET rates are accumulated over periods of either 3 or 6
seconds. In addition there is a single rate with 0.1 sec time
resolution. Some rates are subcommutated, and it takes 96 seconds to
sample them all. STATUS DATA, giving the status of the PET internal
calibrator are contained in one byte appended to the Rate Data. PET
History Packets include 192 second samples of 25 of the rates as well as
Housekeeping Data.

EVENT DATA consist mainly of energy loss measurements for individual
electrons and nuclei that are analyzed by the instrument. The 56-bit
format includes four 10-bit pulse heights from detectors P1 to P3, and
the sum of P4 to P7. Most of the remaining bits describe the state of
various discriminators. The PET bit rate allocation allows only a
fraction of PET events to be telemetered, and a built-in priority system
selects a

representative sample of electron and nuclei events in different energy

intervals.

HOUSEKEEPING DATA include values for two thermistors located in the PET
telescope and on the analog electronics board.

#### 2.2.4.2 Analyzed Science Data

PET is designed to measure the energy spectra of electrons from 0.3 to
30 MeV and of H and He isotopes from \~18 to 70 MeV/nuc. In addition a
PET backup mode can identify elements from H to Ni (Z=1 to 28) with
limited isotope resolution from Z = 1 to 10. These data are used to
study the origin, acceleration, and transport of energetic particles
from solar, galactic, and magnetospheric sources, including high energy
electrons that may play a role in the chemistry of the upper atmosphere.
Among the PET counting rates are electron and proton rates that will
provide the time history of both solar and magnetospheric particle
fluxes.

## 2.3 DATA ARCHIVING AND ACCESSIBILITY

The University of Maryland is the single point of delivery for Goddard
Space Flight Center to the Science Working Group. The University of
Maryland operates the Science Operations Center (UMSOC). Level 1
processing of the data is done at the UMSOC. The Level 0 data received
from PACOR are archived at the UMSOC on rewritable optical disk. The
Level 1 data product (Master Data Files) are archived at the UMSOC, and
copies containing approximately 10 days of data are delivered to the
Co-I institutions for further analysis and to the NSSDC for long-term
archival. The Co-I institutions are located at Goddard Spaceflight
Center, Aerospace Corporation, Langley Research Center,
Max-Planck-Institut at Garching, and Caltech.

An advisory committee has been formed for SAMPEX for the purpose of
establishing a coordinated data processing and archiving plan. The
committee includes Project Scientist Daniel Baker, Project Software
Manager Richard Hollenhorst, NSSDC Representative Raghaviyenga
Parthasarathy, and Co-Investigators Douglas Hamilton, Richard Mewaldt,
and Berndt Klecker.

### 2.3.1 Data and Software Archiving Plan

The SAMPEX Science Working Group plans to deliver one Level 1 data set
and four Level 2 data sets to the NSSDC as listed in Table 2-7.

#### 2.3.1.1 Master Data Files

The Level 1 Master Data Files will be supplied to the NSSDC on
rewritable optical disk at the same time they are distributed to the
co-investigator institutions. These daily data files are written with
the VMS operating system using the Tennis Format. Currently, the NSSDC
does not have the capability to read or copy these disks. Storage of
this complete, basic SAMPEX science data set at the NSSDC is thus being
undertaken to provide for the secure, long-term archiving of the data
set and to provide eventual access to future users who may need more
than the derived Level 2 products discussed below. A document describing
the SAMPEX MDF files and a library of Tennis read routines will also be
supplied. The Tennis Format is self documenting.

#### 2.3.1.2 30-Second Rate and Flux Averages

A complete set of SAMPEX counting rates from the four sensors, typically
averaged over 30 second periods, will be supplied. These averages will
cover the complete orbit, although their interpretation may vary with
location as the relative fluxes of ions and electrons vary. A subset of
these counting rates, as listed in Table 2-8, will be converted to
fluxes in physical units. Conversion factors appropriate to the polar
cap regions (e.g., low background) will be used. The validity of these
flux calculations at lower latitudes will depend on conditions, and at
times (e.g., during South Atlantic Anomaly passages) will be incorrect.
The 30-s rate and flux average files will be accompanied by spacecraft
position and attitude data, along with magnetic parameters derived from
the IGRF 90 field model, which are necessary for proper interpretation
of the data.

#### 2.3.1.3 Polar Cap Rate and Flux Averages

In addition to the 30-second averages, a complete set of SAMPEX counting
rates will be supplied, averaged over each polar cap pass. The subset of
these counting rates given in Table 2-8 will be converted fluxes in
physical units, which may be used as a monitor of interplanetary
conditions.

#### 2.3.1.4 Formats

The Level 2 data products will be delivered in Standard Formatted Data
Units (SFDUs). The SFDU headers will uniquely indicate the format of the
record. An SFDU format catalog will be delivered identifying each SFDU
record format. Special unpacking software shall be delivered for all
compressed data, subcommed data and the data field formats which do not
comply with IEEE standard data types.

#### 2.3.1.5 Caveats

The SAMPEX Science Working Group will make every effort to supply
accurate fluxes to the NSSDC. However, considerable care must be taken
in their interpretation because of the vastly differing particle
environments encountered over an orbit. To facilitate the interpretation
of the data supplied to the NSSDC, detailed descriptions of the various
channels will be supplied with the Level 2 data. In addition the UMSOC
will maintain a log containing the times or time intervals of
significant S/C events (e.g. safehold periods), instrument status
changes (e.g. changes in microchannel plate bias or periods of gradual
gain change), and other instrument information which may be useful.
Copies of this log will accompany Level 2 data submissions.

#### 2.3.1.6 Period of Archival at the UMSOC

The UMSOC will archive the Level 0, Level 1 and Level 2 data products
for a period of 10 years after receipt of the data.

Table 2-7

SAMPEX Data To Be Delivered to the NSSDC

+------------------+------------------------+-------------------------+
|                  | Data Type              | Format/Media            |
+------------------+------------------------+-------------------------+
| LEVEL 1 DATA     | MDF Files              | Tennis Fmt, VMS         |
|                  |                        | written/                |
|                  |                        |                         |
|                  |                        | Rewritable Optical Disk |
+------------------+------------------------+-------------------------+
|                  |                        |                         |
+------------------+------------------------+-------------------------+
| LEVEL 2 DATA     | 30-sec Rate Averages   | SFDU / 8mm tape or      |
|                  |                        | electronic              |
|                  | All Rate Channels      |                         |
+------------------+------------------------+-------------------------+
|                  |                        |                         |
+------------------+------------------------+-------------------------+
|                  | 30-sec Flux Averages   | SFDU / 8mm tape or      |
|                  |                        | electronic              |
|                  | Selected Channels      |                         |
+------------------+------------------------+-------------------------+
|                  |                        |                         |
+------------------+------------------------+-------------------------+
|                  | Polar Cap Averaged     | SFDU / 8mm tape or      |
|                  | Rates                  | electronic              |
|                  |                        |                         |
|                  | All Rate Channels      |                         |
+------------------+------------------------+-------------------------+
|                  |                        |                         |
+------------------+------------------------+-------------------------+
|                  | Polar Cap Averaged     | SFDU / 8mm tape or      |
|                  | Fluxes                 | electronic              |
|                  |                        |                         |
|                  | Selected Channels      |                         |
+------------------+------------------------+-------------------------+

Table 2-8

Selected SAMPEX Counting Rate Channels to Be Converted to Fluxes

  ------------- ------------ ----------------- -----------------------------
  Instrument    Channel      Energy Range      Dominant Particle Type

  LEICA         SSD          \> 0.8 MeV        Ions

                             \> 0.6 MeV        Electrons

                LoPriority   0.5-6.6 MeV/nuc   Z≥2 (mainly helium)

                HiPriority   0.49-8.3 MeV/nuc  Z\>2

                                               

  HILT          HE1          4-9 MeV/nuc       Helium

                HE2          9-38 MeV/nuc      Helium

                HZ1          8.2-42 MeV/nuc    Z\>2

                HZ2          42-220 MeV/nuc    Z\>2

                                               

  MAST          M12          5-10 MeV          Z≥1 (mainly protons)

                Z2           8-15 MeV/nuc      Helium

                Hi-Z         18-50 MeV/nuc     Z\>2

                                               

  PET           ELO          2-6 MeV           Electrons

                EHI          4-15 MeV          Electrons

                PLO          19-28 MeV/nuc     Z≥1 (mainly protons)
  ------------- ------------ ----------------- -----------------------------

Note: Z\>2 energy ranges are for oxygen.

### 2.3.2 Schedule for Data Delivery

The Level 1 Master Data Files will be delivered to the NSSDC within
approximately two months of receipt of data. The four Level 2 data
products will be supplied to the NSSDC within two years of receipt data
to allow for calibration verification and data validation.

### 2.3.3 Data Format Standards

The data format standards which apply to SAMPEX housekeeping data can be
found in the SAMPEX Telemetry and Command Handbook (GSFC-S-740-90-968).
Science packet standards, data formats and conventions are documented in
the Telemetry Packet Description for the SAMPEX Data Processing Unit and
the DPU and Sensor Command Description. The instrument processing
schemes and algorithms are presented in the DATA Handling Strategy for
the SAMPEX DPU.

### 2.3.4 Archive Media

The Level 2 data products will be delivered to the NSSDC on 8mm tape, or
electronically, or on another medium acceptable to the NSSDC. The Level
1 Master Data Files will be delivered to the NSSDC on 5.25\" rewritable
optical disks.

### 2.3.5 Data Quality

Data quality is maintained at three levels: through the transfer frame
and packet level processing provided by PACOR, through limit checks and
continuity checks performed at the UMSOC and finally, through analysis
of the science instrument data performed during the level 2 processing
and analysis efforts.

### 2.3.6 Data Disposition

At the conclusion of the data archiving period, the SAMPEX data archives
housed at the University of Maryland may be discarded at the discretion
of the University of Maryland/Department of Physics. Disposition of data
archived at NSSDC will be the prerogative of NSSDC and is outside the
scope of this PDMP.

# 

# 3.0 PDMP IMPLEMENTATION, MAINTENANCE AND MANAGEMENT

## 3.1 ROLES AND RESPONSIBILITIES

The Project Data Management Plan is a level 1 requirements document
outlining the major data processing roles for the SMEX Project, the
Principal Investigator\'s team and the Co-Investigator teams. The PDMP
is developed as a joint effort between the Project Scientist, the
Principal Investigator and the Software Manager. The Principal
Investigator is responsible for defining the science data processing
requirements, defining Analyzed Science Data Sets, and assigning the
overall data analysis tasks. The Principal Investigator and the Project
Scientist work with the Project Manager and headquarters personnel in
defining delivery products, schedule and prelaunch budget data. The
Software Manager assists in these activities and assists the SWG in
development of practical approaches to meeting these goals.

## 3.2 CHANGE CONTROL

The PDMP should be baselined and placed under control of the SMEX
Project Level 1 Configuration Control Board. Changes to the PDMP should
be proposed through the SAMPEX Science Working Group and submitted to
the SMEX Project through a Level 1 Change Control Request (available at
the SMEX Project Office).

## 3.3 RELEVANT DOCUMENTATION

A complete list of SAMPEX mission documents can be obtained through the
Small Explorer Project Configuration Management Office, Goddard Space
Flight Center, Code 740.4, Greenbelt, MD, 20771. The SMEX Project office
can be contacted by telephone during normal business hours at
301-286-7417 (Project office) or at 301-286-7599 (CM office).