Experiment Requirements
Document (ERD)
for the
OPREX Spacecraft
Evaluation Module (OSEM)
Version 1.2
18 June 1997
"DISTRIBUTION C. Distribution authorized to US Government agencies and their contractors; Administrative or Operational Use; 3 Oct 96. Other requests for this document shall be referred to SMC/TELS, 3550 Aberdeen Ave SE, Kirtland AFB NM, 87117-5776."
"DESTRUCTION NOTICE- Destroy by any method that will prevent disclosure of contents or reconstruction of the document."
Approved By: __________
Col Thomas Mead Date
Program Manager
Space Test Program
__________
Col TBD Date
OSEM Program Manager
Rome Laboratory
TABLE OF CONTENTS1. SCOPE 61.1 NOMENCLATURE 62. EXPERIMENT DESCRIPTION 72.1 Purpose 72.2 Objectives 72.3 Orbit Selection 72.4 Launch Window 72.5 Concept of Operations 82.6 On-orbit Life 83. PHYSICAL DESCRIPTION 93.1 Components 93.2 Axial Conventions 93.3 Dimensions 93.4 Mass Properties 93.5 Interconnections 113.6 Mounting and Alignment 113.6.1 Mounting 113.6.2 Alignment 123.6.3 Field of View, Field of Regard 123.7 Component Motions 144. ENVIRONMENT REQUIREMENTS 154.1 Static Load Constraints 154.2 Vibration Constraints 154.3 Shock Constraints 154.4 Radiation Constraints 164.5 Electromagnetic Interference 164.6 Magnetic Fields 164.7 Atmospheric Pressure Constraints 174.8 Cleanliness Constraints 174.9 Humidity Constraints 174.10 Thermal Constraints 174.10.1 Temperature Limits 174.10.2 Component Thermal Characteristics 174.10.2.1 Heat Sources 174.10.2.2 Thermal Mass 174.10.2.3 External Surfaces 175. ELECTRICAL INTERFACES 195.1 Electrical Power 195.1.1 Power Supply 195.1.2 Power Conditioning and Regulation 195.1.3 Power Supply Circuit 195.1.4 Grounding and Isolation 205.1.5 Power Consumption 205.2 Electrical Signals 215.2.1 Analog Signals 215.2.1.1 OSEM Analog Outputs 215.2.1.2 OSEM Analog Inputs 215.2.2 Discrete Digital Signals 215.2.2.1 OSEM Digital Outputs 215.2.2.2 OSEM Digital Inputs 215.2.3 Serial Digital Signals 225.2.3.1 RS-422A Characteristics 225.2.4 Data Ground Reference 226. ATTITUDE CONTROL REQUIREMENTS 296.1 Accuracy 296.2 Knowledge 296.3 Rotation Rates 296.4 Pointing Duty Cycle 297. COMMAND AND DATA HANDLING 307.1 General Requirement 307.1.1 Data Packet Size 307.1.2 Telemetry Data Sample Rate 307.1.3 Memory 307.1.4 On-Orbit Programming 317.1.5 Time Code Generation 317.2 Telemetry Data Collection 317.3 Redundant Command Capability 318. COMMUNICATION REQUIREMENTS 328.1 Frequency Allocation 328.2 On-orbit Frequency Selection 328.3 Spacecraft Support Contacts 328.4 Data Encryption 329. GROUND SYSTEMS 339.1 Architecture 339.2 Human Machine Interface 349.3 Crewing 349.4 Training 3410. GROUND INTEGRATION AND TEST REQUIREMENTS 3510.1 Potential Hazards 3510.2 Payload Integration and Test 3510.3 Launch Base Processing 3611. LAUNCH AND ORBIT REQUIREMENTS 3711.1 Launch Phase 3711.1.1 Trajectory Parameters 3711.1.2 Operation 3711.2 On-Orbit Check-Out 3711.3 Nominal Operations 3711.3.1 Payload Data Storage 3712. SECURITY 3813. RECEIVABLES AND DELIVERABLES 3913.1 Receivable from Experimenter 3913.2 Deliverables to Experimenter 39APPENDIX A: Interface Drawings 40APPENDIX B: RS-442A Interface 44
List of Figures
Figure 3.4-1 Spacecraft Axis Definitions 10Figure 3.6-1 OSEM Interconnection Diagram 12Figure 5.2-1 DA Voltage Monitor Output Circuits 23Figure 5.2-2 SC Telemetry Monitor Input Circuit 23Figure 5.2-3 RFA Voltage Monitor Output Circuits (1 of 2) 24Figure 5.2-4 RFA Voltage Monitor Output Circuits (2 of 2) 25Figure 5.2-5 OSEM Temperature Monitor Output Circuits 26Figure A-1 PMDA Mechanical Interface (1) 40Figure A-2 PMDA Mechanical Interface (2) 41Figure A-3 PMDA Mechanical Interface (3) 42Figure A-4 PEDA Mechanical Interface 43
List of Tables
Table 2.3-1 Orbit Parameters for OSEM 7Table 3.4-1 OSEM Component Dimensions and Mass Properties 10Table 3.6-1 OSEM Electrical Interface 13Table 4.1-1 Static Load Constraints 15Table 4.2-1 Vibration Constraints 15Table 4.3-1 Shock Constraints 15Table 4.5-1 Ferromagnetic Composition 16Table 4.10-1 Temperature Limits 17Table 4.10-2 Thermal Power Dissipation 18Table 4.10-3 Thermal Mass 18Table 5.1-1 Power Supply Requirements 19Table 5.1-2 Power Consumption Profile 21Table 5.2-1 Analog Output Signals 22Table 5.2-2 Discrete Digital Outputs from OSEM 27Table 5.2-3 Discrete Digital Inputs to OSEM 27Table 5.2-4 RS-422A Characteristics 28
This document contains the specific requirements of the OPREX Spacecraft Evaluation Module (OSEM) experiment. It provides experiment requirements in the areas of flight systems, interfaces, integration and test, and flight operations. All requirements identified in this document shall be contractually binding. Specific text within this document that is informational in nature or could constitute a derived requirement is identified with italics.
For the purposes of this document, the following nomenclature has been adopted. The OPREX Spacecraft Evaluation Module (OSEM) refers to an experiment, part of which consists of flight hardware to be incorporated on a spacecraft (SC) built by the SC contractor. OSEM technical and management personnel are known collectively as experimenters, with associated OSEM contractors.
The following nomenclature terms are found in this document.
ACS SC Attitude Control System (attitude sensors and closed-loop attitude
control elements)
CDH Command and Data Handling System (SC assembly containing one or more
CPUs used to monitor and control SC functions)
GCS SC Ground Control Station (contractor furnished stations used to
communicate with UHFT)
DA Digital Assembly (part of the experiment)
GPSA GPS Antenna (part of the experiment)
MEGS Mission Experiment Ground Station (experimenter built and operated
unit)
OPREX Optical Radiation Experiment
OSEM OPREX Spacecraft Evaluation Module (the Experiment)
PA Parabolic Antenna (experimenter furnished narrow-beam antenna)
PAA Parabolic Antenna Assembly (Assembly consisting of the PA, PMDA, &
PEDA)
PCCA, Power, Signal, and Antenna Cross-Connect Assemblies (experimenter
SCCA, furnished units which provide for cross-connection of the redundant
ACCA experiment assemblies under command from the CDH)
PEDA Parabolic Electrical Drive Assembly (experimenter furnished control
unit which accepts commands from the DA and provides power and
steering commands to the PMDA)
PMDA Parabolic Mechanical Drive Assembly (experimenter furnished
electro-mechanical assembly which supports and points the PA using
power and commands from the PEDA)
PSA Power Supply Assembly (part of the experiment)
RFA RF Assembly (part of the experiment)
SC The TSX-6 spacecraft
SV Space Vehicle: The TSX-6 spacecraft with all experiments integrated
UHFT The SC UHF Transceiver (used with the CDH to communicate command and
telemetry data with a GCS). UHF is for nomenclature only. Actual
frequency to be used is TBD.
UHFA UHF Antenna (SC Antenna for the UHFT)
WBA Wide Beam Antenna (experimenter furnished)
- EXPERIMENT DESCRIPTION
- Purpose
The purpose of OSEM is to evaluate small-signal detection methods and multi-modulation techniques in a dense signal environment. The need for reliable closed loop communication between spacecraft to a ground station back to a spacecraft with minimal error is an ever present need. Being able to perform and calibrate this activity worldwide and in all LEO environments requires substantial exploration of communication methods and techniques to overcome the impediments posed in the layered ionosphere. Assessment of link data between flight hardware and OSEM ground stations will allow for correlation with other ionospheric research programs.The TSX-6 Spacecraft shall support this purpose.
The principal objective is to collect and evaluate a data-base of selected, scientific information associated with small- signal links between spacecraft and ground stations. These objectives are realized by use of a spacecraft (SC) which will support the OSEM electronics boxes and externally mounted antennas. These antennas include a narrow beam Parabolic Antenna, a Wide Beam Antenna, and a GPS antenna.
The experiment utilizes and evaluates several modulation and detection techniques under a variety of natural, man-made, earth, and deep space interference conditions to determine the frequency and power density required to optimally perform closed-loop communications. OSEM will measure and calibrate the amount of absorbed energy in the laminate layers between a space based energy source and the Earth's surface and to quantify the amount of RF attenuation along that same path. Experiment data will assess and quantify communications phenomena.
Requirements of OSEM are shown in Table 2.3-1. The primary goal is a circular orbit at an altitude of 450 nmi. The final orbit shall not be harmonic (exactly 14 orbits per 24 hrs). (For a 98.6 inclination, an altitude of 475+/-5 nmi should be excluded). The SC shall be designed to operate in the space environment defined by these orbits and shall ensure these requirements are presented to the launch vehicle contractor.
Table 2.3-1 Orbit Parameters for OSEM
Parameter Nominal Tolerance Units
Value
Apogee 450 -50 +50 (nmi)
Perigee 450 -50 +50 (nmi)
Inclination 90 -8 +8.6 (deg)
Eccentricit 0.000 -0 +0.013
y
- Launch Window
Launch of OSEM carries no coordination constraint with any other event or activity.
The experiment consists of a unique orbiting transponder system which communicates with a dedicated Mission Experiment Ground Station (MEGS). The MEGS uploads experiment commands, test parameters, and test schedules to the experiment for a particular investigation. The experiment executes the tests as scheduled, including subsequent exchanges with the MEGS, and then downloads the test results to the MEGS. Experiment command, control, and data communications are independent of the SC command and control link (CDH, UHFT) and ground station (GCS), except for the alternate data path described later.
The MEGS is used with OSEM both as a command and control link and a closed-loop test link. Both a wide-beam antenna and a steerable narrow-beam parabolic antenna are used by the experiment to communicate with the MEGS and to collect experiment data based on both spatially dispersed and spatially concentrated radiation and noise patterns. A zenith-facing antenna is used with the GPS receiver to maintain knowledge of the location of the spacecraft.
Control and monitoring of the SC will be accomplished using any GCS over the UHFT-CDH link. The SC contractor is responsible for providing the three GCS sets and their supporting hardware, software, and operator training, as described in Section 9. One GCS will be co-located at the MEGS site while another will be used by the SC contractor for pre-launch checkout and initial post launch operation, SC checkout, and anomaly resolution. At the experimenter's discretion, it will then be transferred to a TBD location. The third GCS will be delivered to the experimenter and installed at a TBD location. The experimenter will operate the SC from any GCS as needed. The SC contractor will provide post launch support on an as needed basis for the life of the SC.
As a backup to the MEGS, Experiment data may also be transmitted through the GCS to the CDH. A serial data connection between the experiment and the CDH function permits blocks of data to be transferred between the experiment and the GCS via the CDH-UHFT. This capability requires that the UHFT to GCS link be covered by government approved encryption. The experiment provides additional encryption on the data transferred between the experiment and the CDH function as well as on the experiment to MEGS link.
The SC will have an emergency command capability as described in section 7.3.
On-orbit life shall be a minimum of three years, with a goal of five years. Life is measured beginning from the time the SC and OSEM are on orbit and have completed initial checkout to the satisfaction of the government. The entire SC shall have a demonstrated reliability of 90% over the three year life of the SC. Reliability should be determined using MIL-HDBK-217F as a guideline.
The experiment consists of a dual redundant communication transceiver and power supply, a dedicated GPS receiver and its antenna, a steerable narrow-beam parabolic antenna, a fixed wide-beam communications antenna, and a cross-connect assembly. Specifically, these consist of two RF Assemblies (RFA), two Digital Assemblies (DA), two Power Supply Assemblies (PSA), three Cross-Connect Assemblies (PCCA, SCCA, ACCA), a Parabolic Antenna Assembly (PAA) comprised of the Parabolic Antenna (PA), the Parabolic Mechanical Drive Assembly (PMDA) and the Parabolic Electrical Drive Assembly (PEDA), a Wide Beam Antenna (WBA), and a GPS Antenna (GPSA). OSEM components and the PAA are illustrated in Figure 3.6-1. The SC ground support equipment is described in section 9.
The cross-connect assembly provides for selection of one RFA, one DA, and one PSA and their interconnection, and for their connection to the single GPSA, the WBA, PAA, and the SC such that one complete set of experiment elements is operational at one time.
The GPSA is a planar patch type antenna which provides nearly hemispheric coverage looking away from earth. This antenna is in addition to any other GPS antennas required by the spacecraft. The WBA is a bifilar helix antenna mounted to face the earth and provide coverage over a half-angle cone of 67°. RF energy is furnished to the WBA by the experiment RFA.
The PAA provides a narrow-beam steerable parabolic antenna (PA), which can slew to any visible point on the earth. Mobility is provided by the PMDA's cross-track and in-track (roll and pitch) drive units which compensate for the angular momentum and center of mass motion of the PA and associated movable antenna mounting structures. The PEDA is a microprocessor controlled stepper motor driver which accepts pointing commands from the experiment DA and powers and controls the two PMDA stepper motors to mechanically steer the PA. The PEDA provides limited status discretes back to the DA and provides full status and position information to the CDH for delivery as telemetry to a GCS. RF energy is furnished to the PA by the RFA.
The SC shall provide all physical parameters necessary for installation and functioning of these components.
In this document, SC axes are defined as shown in Figure 3.4-1.
Dimensions of OSEM components are given in Table 3.4-1. change to requirements language
Masses of the components are listed in Table 3.4-1. The not to exceed (NTE) weight of all OSEM components is 180 lbs. Weights are based on actual hardware measurements or estimations for new or upgraded components. The CG of each assembly may be assumed to be in its geometric center. Inertia properties are TBD. The PMDA mass moments of inertia in the caged position are Ixx = 2738 lbm-in2, Iyy = 1947 lbm-in2, and Izz = 4078 lbm-in2. change to requirements language
Figure 3.4-1 Spacecraft Axis Definitions
Table 3.4-1 OSEM Component Dimensions and Mass Properties
Qty Length* Width* Height Weight Weight Reference
(in) (in) (in) (lbs) (lbs)
each total
RFA 2 12.82 12.11 3.77 19.0 38.0 1
DA 2 12.74 12.0 3.9 12.4 24.8 1
PSA 2 12.74 12.0 3.0 10.0 20.0 1
PCCA 1 6.0 4.0 3.5 3.0 3.0 2
SCCA 1 12.0 4.0 3.5 3.0 3.0 2
ACCA 1 5.0 6.0 3.5 5.0 5.0 2
GPSA 1 5.25 diameter 1.23 0.63 0.63 1
PA 1 36.12 diameter 17.14 1,5
PEDA 1 9.4 2.25 5.1 4.0 4.0 2
PMDA 1 31.5 36.3 38.2 41.0 41.0 2,4
WBA 1 2.63 diameter 12.66 0.75 0.75 1
Experiment Set N/A N/A N/A N/A 15.0 2,3
Interconnect
Cables
Management N/A N/A N/A N/A N/A 24.82
Reserve
Total 180.0
* The length and width dimensions represent the mounting face of each component.
(1) Weight determined from measurement of previous flight.
(2) Estimated weight.
(3) Includes only cables provided by experimenter.
(4) Caged position of PMDA including PA. The PMDA weight includes
the weight of the PA.
(5) The weight of the PA is included in the PMDA.
The experimenter will provide all intra-experiment cables. The experimenter will furnish both halves of mating connectors for all intra-experiment cables and the experiment side of all SC cables that interface to the experiment. The experimenter will provide one flight and two spare sets of mating connectors to the SC contractor. The experimenter will provide the SC bulkhead connectors for all experiment GSE ports and any required flight jumpers. The SC contractor shall provide GSE cables from the experiment GSE connectors to the SC bulkhead connectors. The experimenter will be responsible for all RF cables with lengths to be provided by the SC contractor. Responsibility for different cables and connectors is identified in Figure 3.6-1. The SC contractor shall use connector savers on all experiment interfaces until final mating before launch.
Figure 3.6-1 schematically represents the OSEM and PAA interconnections. Table 3.6-1 lists the connections between the SC and OSEM components. The RS-422 cable between the SCCA and CDH includes an external test connector. Connection of experiment GSE to this connector disconnects the experiment from the SC RS-422 bus. The experimenter will provide the flight jumper and two spares for this connector.
Internal and external clearances for experiment connectors and cables are TBD. Test connectors identified in Figure 3.6-1 shall be made available to the experimenter for integration and test purposes. Experiment test connectors shall be accessible from the exterior of the SC. The PEDA contains three D-Subminiature connectors requiring 1.5 in clearance on the 9.4 x 2.25 in side.
RF cable runs shall be selected so that transmission loss between the ACCA and the bulkhead connector is less than 0.4 dB for the PA signal and less than 1.2 dB for the WBA.
The SC shall accommodate internal mounting of two RFAs, two DAs, two PSAs and three cross-connect assemblies - the PCCA, SCCA, and ACCA. The RFA and DA can either be mounted separately or stacked with the DA on top of the RFA with only the RFA mounted to the SC. The SC contractor has the option of installing these assemblies in either configuration as necessary to meet footprint, balance, or thermal constraints. A stacked DA-RFA is designed to accommodate heat dissipation of both units.
The SC contractor shall be responsible for positioning the antennas on the spacecraft and providing bandpass filtering and shielding as needed on the UHFT link to prevent interference from and interference to experiment signals.
The SC contractor shall design suitable hardware to mount the PAA to the SC. Interface drawings of the PAA are located in Appendix A. The PMDA shall be mounted using eight #10-32 mounting bolts. The mounting face of the PMDA is 6.73 in x 10.69 in. The PMDA also includes four alignment pins to provide repeatable, accurate mounting. The PEDA shall be mounted internally using four #8-32 bolts.
Figure 3.6-1 OSEM Interconnection Diagram
Mounting alignment of the antennas must allow the aggregate system to meet the steering resolution requirements. The PMDA shall be attached to the nadir facing side of the SC, aligned to within 0.1° half-angle cone about the nadir pointing axis of the SC, and aligned to within 0.1° of an established yaw reference. The alignment shall be measured to within 0.05° at the time of installation and after environmental testing. The GPSA boresight shall be aligned within a 1.0° half-angle cone about the zenith. The WBA boresight shall be aligned within a 1.0° half-angle cone about the nadir in its operational configuration. Alignment of the electronic packages inside the SC is not important providing EMI requirements are met.
Field of View, Field of Regard
The GPSA shall be provided an unobstructed field of view (FOV) within the zenith-facing hemisphere whose axis is the boresight of the antenna.
The WBA shall be provided an unobstructed FOV within an earth-facing, 67° half-angle cone about the boresight of the antenna.
The PMDA shall be provided an unobstructed field of regard (FOR) within an earth-facing, 67° half-angle cone about the nadir axis of the antenna assembly. The base of the cone is defined to be the center of rotation of the PA gimbals. In addition, no SC or experiment components shall intrude in the radiation zone (a 12° half-angle cone centered at the base of the antenna feedhorn) of the PA at any position.
Table 3.6-1 OSEM Electrical Interface
Experiment Seq Spacecraft Function Cable Connector Type
Assembly # Element Description
PEDA 1 CDH Power, Control, 37 Wires #20 DCM37P
Feedback
PMDA 1 RF Signal PA RF Signal RG 142/U 3101-7341-10
(M/A-COM)
2 Pyro 1 Bolt cutter control TBD D Subminiature
3 Pyro 2 Bolt cutter control TBD D Subminiature
PSA-1 1 Power Bus 1 +28V DC Input Power 6 Wires #20 MS27508E10F98P
(QPL)
PSA-2 1 Power Bus 2 +28V DC Input Power 6 Wires #20 MS27508E10F98P
(QPL)
PCCA 1 Power Bus 1 +28V DC Input Power 2 Wires #20 TBD
2 Power Bus 2 +28V DC Input Power 2 Wires #20 TBD
3 CDH Cross-Connect 8 Wires #22 TBD
Command and Status
SCCA 1 CDH/Test TT&C Serial 16 Wires #22 TBD
Connector Interface (RS-422)
2 CDH Telemetry Monitor 30 Wires #22 TBD
Signals
3 CDH PEDA Power Enable 2 Wires #22 TBD
ACCA 1 Bulkhead WBA RF Signal RG 142/U 3101-7341-10
Pass-thru (M/A-COM)
2 Bulkhead PA RF Signal RG 142/U 3101-7341-10
Pass-thru (M/A-COM)
3 Bulkhead GPSA RF Signal TBD TBD
Pass-thru
DA-1 1 Bulkhead Ground Diagnostic 66 Wires #22 TBD
Test Telem/Control
2 Connector 1 Ground Diagnostic 66 Wires #22 TBD
Bulkhead Telem/Control
Test
Connector 2
DA-2 1 Bulkhead Ground Diagnostic 66 Wires #22 TBD
Test Telem/Control
2 Connector 1 Ground Diagnostic 66 Wires #22 TBD
Bulkhead Telem/Control
Test
Connector 2
The PMDA shall have an unobstructed range of motion of 66° off the nadir. The PMDA is software controlled to not slew beyond 63.75° and has hard mechanical stops at 66°. The maximum slew rate is 7.3 °/s. The maximum slew acceleration is 5.44 °/s2.
The dynamic envelope of the PAA is 41.8 in long x 37.1 in wide x 38.2 in tall and is shown in Appendix A. There are no covers that must be removed before flight. However, each time the PMDA is uncaged, the caging mechanism (which contains two pyrotechnic bolt cutters that cut a retainer bolt) shall be refurbished with two new cutters and a retainer bolt. In its stowed configuration, the PMDA shall be rotated 66° in one axis and 0° in the other.
The PMDA is designed to be angular momentum compensated. The residual torque is estimated based on balancing each gimbal axis when the antenna boresight is pointed normal to the PMDA mounting plane. Based on this assumption, the maximum unbalance load inertia on the gimbal motor is approximately 1.5 lbm-in-s2. When attempting a gimbal axis slew acceleration or deceleration of 5.44°/s2, the resulting torque reaction imparted to the spacecraft is 0.14 in-lbf. The SC Attitude Control System shall be designed to accept any torque imparted to the SC as a result of PA motions and still maintain the pointing requirements identified in section 6.
No other components contain moving parts other than small RF switching relays.
OSEM has been designed to withstand loads up to those given in Table 4.1-1. This assumes the OSEM boxes are mounted with the mounting surface normal to the SC Z axis.
Table 4.1-1 Static Load Constraints
Axis Maximum Load (g) x +/-8.5 y +/-8.5 z +/-10.0
- Vibration Constraints
OSEM components have been designed to withstand random vibration spectral densities up to those given in Table 4.2-1. The SC structure shall be designed to preclude OSEM components from experiencing loads greater than these.
Table 4.2-1 Vibration Constraints
Frequency Range Requirement 10 Hz to 20 Hz +6 dB/octave slope 20 Hz to 100 Hz 0.015 G ˆ 2/Hz 100 Hz to 200 Hz +6 dB/octave slope 200 Hz to 1475 Hz 0.05 G ˆ 2/Hz 1475 Hz to 2000 Hz –9 dB/octave slope
- Shock Constraints
SC contractor shall ensure OSEM components are not subjected to shock levels (due to either LV separation or any explosive actuators) greater than those given in Table 4.3-1. In addition, the PMDA contains two bolt cutters to uncage the PA after launch. The shock due to these bolt cutters will also be less than the levels in Table 4.3-1.
Table 4.3-1 Shock Constraints
Frequency Range Requirement 20 Hz 50 G 20 Hz to 1600 Hz 3 dB/octave slope 1600 Hz to 10000 Hz 3600 G
- Radiation Constraints
SC contractor shall ensure OSEM components, except for external antennas, do not receive a total integrated radiation dose of greater than 2,000 RADs silicon per year measured from the outside surface of each component. Analysis shall assume worst case conditions of solar max.
OSEM shall comply with the requirements of MIL-STD-461B, Table 3-2, Class A2a. The experiment shall be tested according to MIL-STD-462. The SC contractor shall ensure OSEM components are not subjected to an EMI environment which exceeds the tolerance level of these requirements.
The power consumed by all oscillators and/or converters within the DA and the RFA (excluding that which is radiated by the transmitting antennas), is estimated to not exceed a total of 0.5 watts. The power consumed by all oscillators and/or converters within the PSA is estimated to not exceed 1 watt (TBD). The power consumed by all oscillators and/or converters within the cross connect assemblies is estimated to not exceed 1.0 watts (TBD). The power consumed by all oscillators and/or converters within the PAA is estimated to not exceed 1 watt (TBD).
The experiment includes digital equipment operating at a variety of clock rates. Also contained are frequency synthesizers, multipliers, and dividers which generate event clocks, mixer injection frequencies, I.F. frequencies, and data frequencies. These signals are in the band from 1 kHz to 1 GHz .
Square wave and pulsed electromagnetic fields are generated by the PSA with a frequency of approximately 200 kHz and odd harmonics. Sinusoidal fields are generated by the RFA in the range from l kHz to 1 GHz, arising from normal use of inductors as circuit elements. Pulsed DC fields exist as the actuating fields of latching coaxial relays. There are no magnetic fields generated other than as a by-product of normal circuit implementations. Some shielding has been incorporated into the design of the RFA, DA, PSA and the PAA. Additional shielding within these packages is not feasible. The SC shall provide any additional external shielding found to be required for OSEM.
The experiment uses only that ferromagnetic material as required in circuit elements such as transformers and inductors. No chassis components are constructed of ferromagnetic materials.The ferromagnetic material composition of OSEM components is identified in Table 4.5-1.
Table 4.5-1 Ferromagnetic Composition
DA negligible RFA 0.2 lbs PSA 0.6 lbs PAA 15.4 lbs (TBD) PCCA TBD SCCA TBD ACCA TBD
- Magnetic Fields
OSEM has no unusual sensitivity to magnetic fields. Squarewave fields will be generated near the roll and pitch motors on the PMDA with frequencies from 0-12.5 kHz. Pulse DC magnetic fields exist which are derived from the DC-DC converters in the PEDA. Use of a resolver as a position indicator will generate sinusoidal magnetic fields at 5kHz.
Atmospheric Pressure Constraints
SC contractor shall ensure OSEM components are maintained in atmospheric pressures of 1 atm or less with a maximum rate of change of 760 torr/per minute.
OSEM components shall be maintained in a class 100k environment. Short periods of exposure to dirtier environments may be allowed with experimenter coordination.
SC contractor shall ensure OSEM components are maintained in 0 to 60 percent relative humidity. SC contractor may briefly allow OSEM components to be exposed to 60 to 95 percent relative humidity, but shall limit such exposure to periods of less than 8 consecutive hours. SC contractor shall ensure no water condenses on any OSEM components. OSEM shall not be operated at humidity levels greater than 75%.
The SC contractor shall ensure that there is adequate thermal conductance between OSEM components and the SC mounting platform to maintain the temperature limits described below.
The SC contractor shall ensure the baseplates of all OSEM components are maintained within the maximum operational temperature range defined in Table 4.10-1 while power is applied to OSEM. When power is not applied, OSEM components shall be maintained within the survival temperature range identified in Table 4.10-1. SC contractor should endeavor to keep component temperature ranges within the nominal range as much as possible. Temperature limits for the PAA are currently TBD, but are expected to fall in the same range as indicated in Table 4.10-1.
Table 4.10-1 Temperature Limits
Range Low (C) High (C) Nominal Temperature -25 +30 Max. Operational Range -25 +45 Survival (Non-operational) -30 +60 Range
- Component Thermal Characteristics
- Heat Sources
Power dissipation levels for OSEM are shown in Table 4.10-2. For a description of power modes and duty cycles refer to section 5.1.5.
The thermal mass of OSEM components by material type is shown in Table 4.10-3.
Surface Finish on all OSEM Internal Components is 32 micro-inches surface roughness, 0.005 inches surface flatness. Surface finishes are painted flat black (FED-STD-595 COLOR 37083) per MIL-F-18264 using primer MIL-P-23377 and a topcoat MIL-C-83286. Exception is the PEDA which is painted black using Lord Corp Z306 low outgassing paint. Mounting surfaces are coated with Chemical Conversion Coating, per MIL-C-5541, Class 3.
Materials used to construct the chassis of OSEM Internal Components are:
DA: 2219-T37 Aluminum per QQ-A-250/30
RFA: 6061-T6 Aluminum per QQ-A-250/11
PSA: 6061-T6 Aluminum per QQ-A-250/11
PCCA: 6061-T6 Aluminum per QQ-A-250/11 (TBD)
SCCA: 6061-T6 Aluminum per QQ-A-250/11(TBD)
ACCA: 6061-T6 Aluminum per QQ-A-250/11(TBD)
PEDA: TBD
PMDA: TBD
Table 4.10-2 Thermal Power Dissipation
Unit Inactive Orbit Typical Orbit Maximum Power
Power (W) Power (W) Orbit (W)
PSA 15.1 15.7 17.1
DA 7.0 7.3 8.1
RFA 6.7 7.3 8.9
PMDA* 0 5.4 17.8
PEDA* 0 0.7 2.0
PCCA* 2.5 2.5 2.5
SCCA* 5.0 5.0 5.0
ACCA* 2.5 2.5 2.5
Total 38.8 46.4 63.9
* Values are TBD
Table 4.10-3 Thermal Mass
Material \ % by DA RFA PSA PCCA ACCA SCCA PEDA PMDA/PA Weight Aluminum 52 57 59 60 60 60 44 8 Copper and Alloys 15 20 15 15 15 15 0 34 Polimide/Glass 26 6 5 5 5 5 30 0 Stainless Steel 3 3 3 5 5 5 4 5 Ferromagnetic 0 2 6 5 5 5 22 28 Material Miscellaneous 4 12 12 10 10 10 0 25 Non-Metals
- ELECTRICAL INTERFACES
- Electrical Power
Primary power will be applied to the experiment shortly after a stable orbit is achieved and will not be removed except for occasional tests or a spacecraft anomaly which requires emergency load shedding to maintain the health of the SC.
The experiment operates in a variety of modes and combinations of modes, as commanded by the MEGS, and the power dissipated varies with mode. For the purpose of defining the power input and heat dissipation requirements, each orbit period of experiment operation is classified as either Inactive, Typical Active, or Maximum Active. A sequence of orbits may consist of any combination of single or repeated orbit types.
For the planned orbit altitude, the orbit period is approximately 101 minutes.
The SC shall supply +28 VDC power to PSA-1, PSA-2, and the PEDA through separate power supply cables. The power supply shall comply with Table 5.1-1. The active PSA provides power to the active DA and RFA. The PCCA receives power from the SC via the PSA power lines and supplies power to the SCCA and the ACCA (TBD). The PEDA provides power for the PAA.
Table 5.1-1 Power Supply Requirements
Line Volts Max. Current Fuse Rating - Fuse Rating -
(DC) (amps) Primary (amps) Secondary (amps)
PSA-1 +28 +/- 6.76 15 25
4
PSA-2 +28 +/- 6.76 15 25
4
PEDA +28+/- 4 7.5 15 25
Power Conditioning and Regulation
The SC electrical power provided to the PSA and the PEDA shall vary no more than a +/- 4V from the required 28V supply voltage.
The PSA contains an inrush protection circuit such that the input current will attain steady-state after 25 milliseconds with no overshoot. The inrush current on the PEDA is TBD. Ripple on the SC power provided to the experiment shall not exceed 100mV peak-to-peak. Power to OSEM shall also be compatible with MIL-STD-461B, Table 3-II Class A2a.
Power to each load shall be delivered through either of two (primary and secondary) redundant power relays. The primary relay for each circuit is that used in normal operation while the secondary relay is used as an alternate power path in case of failure of the primary relay or its fuse. The primary and secondary power circuits are fused independently with the unequal fuse values in Table 5.1-1. Each power relay is operated by the SC power subsystem under control of the CDH.
The CDH function commands the SC power system to apply or remove power to either or both PSA's as requested via the GCS. In normal operation, only one PSA at a time will be active. Both PSA's may be powered for limited durations for the purposes of anomaly resolution, however power consumption will increase only marginally (TBD). The CDH commands the SC power system to apply or remove power to the PEDA either when requested by a discrete line from the DA, or when requested via the GCS.
For emergency load shedding, the SC power subsystem may command PSA and PEDA power off autonomously. Under all conditions of power turn-off to the experiment, both commanded and automatic, a warm reset discrete (see 5.2.2.2) followed by a serial command message shall be given by the CDH function to the DA not less than eight seconds before the removal of power to permit the DA to save critical data into non-volatile memory. Details of the serial command message and timing are TBD.
An electromagnetic interference (EMI) filter is located within the PSA on the +28 VDC input line from the SC. The filter's characteristics are such that the power supply complies with MIL-STD-461B, Table 3-II, Class A2a.
Grounding and Isolation
The SC shall provide a single-point grounding system for all SC and experiment components.
The chassis of each OSEM component shall be grounded to the SC structure. The resistance between any experiment component and the SC structure shall be less the 2.5 milliohms. A ground lug and ground strap are provided for each component to further enhance grounding to the structure.
RF signals are grounded through the RF cable to the RFA. The antenna is grounded to the SC structure using a ground strap on the base of the PMDA.
Grounding within the DA is accomplished by dedicated ground plane layers within each digital circuit board and the back plane interconnect board. This ground is connected at a single point in the box which is in turn connected to the metal chassis. Voltage outputs from the PSA are floating within the PSA and are single-point grounded in the EMI cavities of the DA and RFA. No current is returned through the chassis.
The PEDA contains two +28V power inputs (used to select primary or redundant controller) that share a common power return. The motor has a separate ground on the PEDA power interface that must be within 0.7 V (TBD) of the power return. An internal jumper will short these grounds if this cannot be accomplished on the SC.
Both the +28 VDC power input line and its return line shall be isolated from the chassis of the PSA and the PAA and from all other circuits and equipment within OSEM with an isolation resistance of greater than 1 Mohm. AC isolation of OSEM shall be such that capacitance less than 0.01 micro-farad shall exist between the power return and chassis.
The SC shall support experiment operations at any time during an orbit, regardless of sunlight conditions. OSEM requires an orbit average power of 60 watts for a maximum activity orbit, based on the single orbit power profile given in Table 5.1-2. The SC contractor shall ensure that battery state of charge does not go below acceptable levels (20% depth of discharge) under worst case environmental conditions. The SC power system shall accommodate any combination of power modes, including multiple maximum active orbits.
Table 5.1-2 Power Consumption Profile
Mode Duration of Power Power into Total
Peak Activity into PSA PEDA (W) Power (W)
(min) (W)
Inactive (OAP) 0 38.8 0.0 38.8
Typical Orbit (OAP) 6.1 40.9 3.1 43.1
Max Active Orbit 20 45.5 8.9 54.4
(OAP)
Peak <4 179.0 164.6 343.6
Data and commands shall be transferred between OSEM and the SC host in three forms: analog signals, discrete digital signals, and serial digital signals.
The SC shall accept analog outputs from the SCCA consisting of voltage monitors and temperature sensors located in the PSA, DA, and RFA. The SCCA will provide telemetry signals only for the active set of PSA, DA, and RFA. The SC shall also accept analog outputs from the PEDA consisting of antenna position information and PAA voltages and temperatures. The SC shall convert the analog signals into telemetry information (See paragraph 7.2). The analog outputs are listed in Table 5.2-1. The SC side of the interface may contain any circuits meeting the functionality identified in Table 5.2-1 and associated figures.
The SC contractor shall also provide a sensor that measures the currents drawn on the +28 VDC power lines by each PSA and the PEDA. The current shall be sampled at programmable (TBD range) rates. This data shall be available to the experimenter as SC telemetry.
No analog inputs from the SC to OSEM are needed.
The SC shall accept CMOS compatible discrete digital outputs from the PSA, the PCCA, and the PEDA. The SC shall convert these digital signals into telemetry information (See paragraph 7.2). The discrete digital outputs are listed in Table 5.2-2.
The SC shall provide CMOS compatible discrete digital commands to the PCCA, SCCA, and PEDA as described in Table 5.2-3.
The SC shall supply a bi-directional serial digital data path between the DA (through the SCCA) and CDH using RS-422A logic levels. The balanced digital data lines shall be within a separate shielded cable.
The SC shall comply with Table 5.2-4. Further implementation details of the RS-422A interface are available in Appendix B (available upon request).
All digital signals to and from the DA are transmitted with respect to the digital ground, which is single-point grounded to the chassis of the DA.
Table 5.2-1 Analog Output Signals
Function From Output Value OSEM Output SC Input
Circuit Circuit
RFA + 8.5 V SCCA 0 to +8.5 Figure Figure 5.2-2
VDC 5.2-3
RFA +15 V SCCA 0 to +15 VDC Figure Figure 5.2-2
5.2-3
RFA -15 V SCCA 0 to -15 VDC Figure Figure 5.2-2
5.2-3
RFA +28 V SCCA 0 to +28 VDC Figure Figure 5.2-2
5.2-3
RFA +43 V SCCA 0 to +43 VDC Figure Figure 5.2-2
5.2-3
RFA + 5A V SCCA 0 to +5 VDC Figure Figure 5.2-2
5.2-4
RFA +5B V SCCA o to +5 VDC Figure Figure 5.2-2
5.2-4
RFA +12 V SCCA 0 to +12 VDC Figure Figure 5.2-2
5.2-4
RFA -12 V SCCA 0 to -12 VDC Figure Figure 5.2-2
5.2-4
RFA +10 V SCCA 0 to +10 VDC Figure Figure 5.2-2
5.2-4
RFA -10 V SCCA 0 to -10 VDC Figure Figure 5.2-2
5.2-4
DA +15 V SCCA 0 to +15 VDC Figure Figure 5.2-2
5.2-1
DA -15 V SCCA 0 to -15 VDC Figure Figure 5.2-2
5.2-1
DA +5 V SCCA 0 to +5 VDC Figure Figure 5.2-2
5.2-1
RFA Temp SCCA -30 to +70°C Figure Figure 5.2-2
5.2-5
DA Temp SCCA -30 to +70°C Figure Figure 5.2-2
5.2-5
PSA Temp SCCA -30 to +70°C Figure Figure 5.2-2
5.2-5
PCCA +28 V (TBD) PCCA 0 to +28 VDC TBD TBD
PEDA Vcc PEDA 0 to +5 VDC TBD TBD
PEDA Vbias PEDA 0 to +15 VDC TBD TBD
PEDA Vmotor PEDA 0 to +60 VDC TBD TBD
PEDA Temp (TBD) PEDA TBD TBD TBD
PMDA Roll Motor PEDA TBD TBD TBD
Temp
PMDA Pitch Motor PEDA TBD TBD TBD
Temp
PA Roll Position PEDA TBD TBD TBD
PA Pitch Position PEDA TBD TBD TBD
Figure 5.2-1 DA Voltage Monitor Output Circuits
Figure 5.2-2 SC Telemetry Monitor Input Circuit
Figure 5.2-3 RFA Voltage Monitor Output Circuits (1 of 2)
Figure 5.2-4 RFA Voltage Monitor Output Circuits (2 of 2)
Figure 5.2-5 OSEM Temperature Monitor Output Circuits
Table 5.2-2 Discrete Digital Outputs from OSEM
Function Signal Levels Experiment Output SC Input
Circuit Circuit
PSA Power Supply +3.5 to +5.3 V = TBD TBD
Fault "OK"
-0.3 to +0.4 V =
"Fault"
PSA Switch Status +3.5 to +5,3 V = "1" TBD TBD
(TBD) -0.3 to +0.4 V = "2"
DA Switch Status +3.5 to +5.3 V = "1" TBD TBD
(TBD) -0.3 to +0.4 V = "2"
RFA Switch Status +3.5 to +5.3 V = "1" TBD TBD
(TBD) -0.3 to +0.4 V = "2"
PEDA Power Supply +3.5 to +5.3 V = TBD TBD
Fault (TBD) "OK"
-0.3 to +0.4 V =
"Fault"
PEDA Power Enable +3.5 to +5.3 V = TBD TBD
from SCCA "Enable"
-0.3 to +0.4 V =
"Disable"
Table 5.2-3 Discrete Digital Inputs to OSEM
Function Levels Experiment Input SC Output
Circuit Circuit
Warm Reset +3.5 to +5.3 = TBD TBD
"NORMAL"
-0.3 to +0.4 V =
"RESET"
PAA Reset +3.5 to +5.3 = TBD TBD
(TBD) "NORMAL"
-0.3 to +0.4 V =
"RESET"
PSA Switch +3.5 to +5.3 = "1" TBD TBD
-0.3 to +0.4 V = "2"
DA Switch +3.5 to +5.3 = "1" TBD TBD
-0.3 to +0.4 V = "2"
RFA Switch +3.5 to +5.3 = "1" TBD TBD
-0.3 to +0.4 V = "2"
PEDA Input TBD TBD TBD
(TBD)
Table 5.2-4 RS-422A Characteristics
Type Bit-serial
Asynchronous
Half Duplex
Format 9600 baud
8 data bits
1 stop bit
Odd parity
Electrical RS-422A levels
Transmit Port Control and Data Presents two-wire complementary differential
Outputs unipolar signal having nominal voltage levels
of 0 volts and +5 volts
Receive Port Control and Data Accepts two-wire complementary differential
Inputs unipolar signal having nominal voltage levels
of 0 volts and +5 volts
Logical 1 Data By agreement between experimenter and SC
contractor
- ATTITUDE CONTROL REQUIREMENTS
Under normal conditions, the SC shall maintain its operational orientation such that the GPS Antenna always looks toward zenith, the Wide Beam Antenna always looks toward nadir, and the Parabolic Antenna is always steerable to any visible point on earth.
The SC shall maintain the boresight of the GPSA within a 2° half-angle cone about the zenith axis. The SC shall maintain the boresight of the WBA within a 1.5° half-angle cone about the nadir axis.
The SC shall maintain the nadir axis of the PAA within a 1.3° half-angle cone about the nadir axis. In addition, the SC shall maintain the PAA within 1.0° of an established yaw reference.
The SC shall determine knowledge of the SC attitude in roll, pitch, and yaw coordinates with a resolution less than 0.75° in each axis. The knowledge data shall be determined and time-stamped at a sample rate set by the CDH based upon ground command. The maximum sampling rate shall be 1 sec. This data shall be provided in SC telemetry.
The experiment has no limitation on the rotational acceleration or velocity of attitude error correction provided the pointing requirements in paragraph 6.1 are maintained.
The SC attitude knowledge and control shall be maintained within the accuracy limits at all times during normal operations.
The SC contractor shall provide means for control and monitoring of the SC using a dedicated GCS, the CDH function in the SC, and a bi-directional radio command and data link between them. This capability shall include all functions required for pre-launch checkout; launch and early orbit operations; control, sequencing, and status verification of deployables; and on-orbit control and monitoring of the SC including setting SC parameters, collecting, storing, downloading, and displaying both SC and experiment telemetry; and detecting and recovering from SC anomalies.
The GCS to CDH link shall be the primary means for applying and removing experiment power and for commanding the PCCA to select a particular experiment configuration. The GCS-CDH link will otherwise not participate in experiment command and control except as noted below.
Provision shall be made for blocks of arbitrary experimenter digital data to be uplinked from the GCS, held in CDH memory, and delivered at a scheduled time to the DA. Provision shall also be made for the CDH to accept from the DA blocks of arbitrary digital data, hold the data in CDH memory, and deliver the data to the GCS on a scheduled basis.
The SC contractor shall packetize the uplink and downlink data as appropriate to efficiently control and monitor the SC. The data path to and from the DA shall accommodate delivery and storage of data blocks of up to 64K bytes. The integrity of these data blocks shall be maintained during transmission, storage, and transfer to the DA.
The rate of sampling of individual telemetry data items shall be programmable through the GCS with provision for a sample rate of up to one sample per second and a block size of up to 30 hours of telemetry collection except that the sample rate may be reduced for longer telemetry collection intervals. Details TBD.
The SC shall provide on-board memory for storage of at least 4 MB of experiment data. The SC shall dynamically allocate this to store up to 84 separate experiment data blocks as variable size mailboxes of up to 64 KB.
The SC shall provide for uploading experiment data to SC mailboxes via the GCS, storing the data in the SC indefinitely, and delivering the data to the Experiment on a scheduled or commanded basis. The SC shall provide for accepting a return message or data block in return for each data block delivered to the Experiment, for storing each return message or data indefinitely in separate mailboxes, and for delivering the messages or data from selected mailboxes to a GCS on a scheduled or commanded basis.
The SC shall provide means for verifying to the GCS that data for each mailbox was delivered or received error free. The SC shall also provide a means for automatically retransmitting any data block not delivered error free.
The SC shall provide the capability for primary SC software to be stored in EEPROM (read only on orbit) and for a secondary, upgradeable copy to be used upon command. At launch, both memories shall be loaded with all flight software. Software may be switched between primary and secondary based upon ground command through either standard or emergency commanding. Under all conditions of CDH reset, the SC shall default to operating with the primary software set. Provision shall be made to download software completely or in parts from either primary or secondary memory for analysis and verification, to upload software changes, or to upload a complete new software set to the secondary memory of the SC. The SC contrator shall be responsible for producing and verifying all SC software, including patches required on orbit.
The SC shall maintain an internal real-time clock for use in executing its own scheduled events and for timetagging collected telemetry. Experiment science data transferred to the ground either through the MEGS or GCS will be timetagged by the experiment internal clock. There is no requirement for the SC and OSEM internal clocks to be synchronized. The GCS shall have the capability to display, verify, and set the SC clock. The SC and GCS clocks shall be synchronized to within 2 sec of UTC.
In addition to SOH telemetry for control and monitor of the SC, the SC shall collect, time-tag, and store all experiment outputs identified in sections 5.2.1.1 and 5.2.2.1 and downlink this data to the GCS upon command. This data shall also be available to the experimenter during pre-launch ground testing. The SC shall also collect SC state of health telemetry for use by the experimenter, including as a minimum battery voltage, temperature, load current, charge current, and estimated state-of-charge, solar array temperature and current, other SC module and surface temperatures, status of SC systems, SC attitude error as reported by the ACS, estimated SC attitude. Battery voltages shall be monitored within 100 mV.
The SC and GCS shall provide a control channel to the SC which allows for failsafe emergency commanding of critical SC functions. This channel shall operate at the same frequency as the UHFA, be suitably encrypted, receive only and shall always be powered while on orbit but may include power cycled circuits for SEU recovery. SC telemetry shall be available which indicates the readiness of this capability. This capability shall, as a minimum, command the following events:
a) execute a warm reset of the CDH function;
b) remove and reapply power to the SC;
c) switch operation of the CDH function from between primary and secondary software sets;
d) command power off and power on to either PSA;
e) set the cross-strap configuration of the Experiment by asserting discretes to the PCCA;
f) set the default cross-strap configuration for the PCCA to be used by the CDH function at reset or power-up events;
g) change the default configuration of redundant SC features; and
h) control the ability of the SC to transmit.
Detailed frequency assignments for the SC/GCS TT&C subsystem are dependent on the command and control solution proposed by the contractor. The selection of the frequency and the pursuit of official assignment of that frequency shall be the responsibility of the contractor and sponsored by the Government. Preliminary discussions with the Air Force Frequency Management Agency indicate that TSX-6 will need to operate in the UHF band (225-399 MHz) or in the Mobile Satellite Communications band (1626.5-1645.5MHz uplink and 1530-1559 MHz downlink). The uplink and downlink frequencies may be the same. The closed loop communications link margins shall be greater than TBD dB.
As an aid to surviving in-band interference on the SC/GCS TT&C link, both the GCS and SC Xmit/Rcvr components shall be frequency programmable from the ground over TBD range. The assigned frequency shall be the default for both the GCS and the SC.
During normal operations, the SC/GCS link will support contacts for all passes in which the SC is within view of a GCS with a pass elevation exceeding 10°. Each GCS shall have a 99% probability of successfully executing at least one support contact during a 24 hour period, regardless of the weather conditions at the GCS. The delivered bit error rates (BER) for nominal contacts shall be 10-6 or better from the GCS to the CDH. The GCS-SC link shall packetize the link data and incorporate ack/nak or other suitable protocols at the packet level to assure that packets which are received in error are automatically requested for retransmission until delivered without error or the link is no longer able to close due to pass geometry. In addition, the SC processor shall perform command validation upon all received commands. For each exchange attempted, the GCS SC data link shall display data exchange quality including failure to successfully upload or download data.
The SC shall be capable of continuing normal operations (performing scheduled events) for up to 168 hours without a support contact. At the end of this period the SC comm system shall go into "beep-receive" mode and, if adequate power is available, the SC should maintain normal operations (ACS within limits and experiment powered on) (TBD). The SC should be capable of maintaining this mode indefinitely. In addition, the SC shall be able to store up to 48 hours of SOH telemetry at the minimum sample rate (0.1 Hz) without a telemetry buffer overflow.
All communications between the SC and the ground shall be encrypted using an NSA approved (TBD) encryption device. Provision may be made to bypass the encryption function during anomaly resolution. Additionally, experiment data will be encrypted with an experimenter provided encryption method.
The SC contractor shall procure three Ground Control Stations (GCS). The MEGS will be procured and operated solely by the experimenter. The GCS shall execute all SC command and telemetry sessions, including all experiment command and telemetry collections described in Sections 7 and 8. In addition, the GCS shall be capable of relaying downloaded experiment data to the experimenters using commercial telephone lines. One GCS shall be used by the SC contractor for pre-launch and post-launch checkout, early anomaly resolution, and on-orbit support as needed. Ultimately it will be delivered to the experimenter. The second GCS shall be delivered to the experimenter's facility at least six weeks before launch for use in early orbit checkout and will continue to be the primary GCS for the life of the SC. The SC contractor is not responsible for installation at the experimenter's facility. The third GCS will be delivered to a TBD location to support experiment activities. For purposes of frequency assignment, the third GCS may be assumed to be a backup for the first two.
The SC contractor shall define the hardware for all GCS components (including antennas, transceivers, encryption units, and computer interfaces), develop and integrate the software, verify correct operation of the GCS with the SC, write operations manuals, and provide GCS operator training to the experimenter at least 6 weeks prior to launch.
The SC contractor shall design, construct, and test each GCS to operate the SC. Any GCS shall be capable of exchanging commands, data, and other files between stations. In addition, a GCS should be capable of remotely operating any other GCS during SC contacts using commercial telephone or other (TBD) comm links (such as ISDN). SC commands and data shall be encrypted during transfers between GCS's. The GCS's should be constructed using Commercial-Off-the-Shelf (COTS) components to the greatest extent possible.
The GCS shall provide the capability to separate SC telemetry from experiment data, and to format data for distribution as printed copy, on magnetic media (e.g. disk or tape), or to another computer via a data link. The GCS shall also accept experiment data for uplink received on a floppy disk or over a dial-up connection. Experiment data shall be received and remain encrypted while under the control of GCS personnel.
The GCS shall provide the capability to immediately display downlinked telemetry and analyze it for anomalies. The GCS shall provide a means to archive telemetry data. The GCS shall also provide software tools to manipulate collections of telemetry data for long term trend analysis. Other features of the GCS tool suite should include low-level delete capability (DoD Wipe), orbit propagation and contact scheduling software, power modeling and trend analysis, the ability to acquire, read, and process 2 line element sets and other ephemeris products from government sources, the ability to generate customizable telemetry displays, and userid and password access to GCS software.
Any antennas and associated mounting equipment shall be semi-portable (non-permanent installation) and meet the following environmental requirements: TBD.
The SC command and control, telemetry monitor, data uplink and downlink shall be operator controlled at the GCS through a windowed graphical user interface. All data shall be displayed in either raw format as received or converted into meaningful engineering units as defined in operations documentation. The GCS hardware and software shall be capable of performing a scheduled contact without human intervention.
The contractor shall provide sufficient crew resources to provide on-site technical support for planning and execution of all scheduled SC contacts whenever a GCS is resident at the contractor's location and used as the primary GCS. In addition, the contractor shall provide full engineering support for the duration of all anomaly operations and be available throughout the mission on an on-call basis.
The contractor shall provide sufficient training to government personnel and associated contractors to conduct nominal operations with the advice of the on-call engineering support. This training shall be accompanied by a complete operations manual and primary training documentation focusing on operations.
The SC contractor shall also provide training and instructions necessary to allow the experimenter to install a GCS.
GROUND INTEGRATION AND TEST REQUIREMENTS
The highest supply voltage present within OSEM is +43 volts +/-10 percent. It is generated within the PSA and fed to the RFA, where it is used in an RF power amplifier. In addition, there is a peak RF voltage of 265 volts at the output of an RF power amplifier. This signal, to a maximum of 700 W peak RF power, is routed through coaxial cable from the RFA to the PA.
The PMDA contains two bolt cutters for the purpose of uncaging the PA after launch. The pyrotechnic bolt cutters are DOT class C bolt cutters, 2 per assembly, containing 55 mg of explosive material each. The bolt cutter is self-contained and emits no gasses or shrapnel when cutting the #10-32 brass bolt. The cutter is further encased in an aluminum housing which contains the cutter and its wiring. The cutter electrical interface is a D-subminiature connector on the housing. The severed retainer bolt is caught and retained in catcher housings. The SC contractor shall be responsible for refurbishing of pyros, if required. At least one deployment is expected.
OSEM contains no pressurized systems, gases, or liquids. OSEM contains no sources of ionizing radiation.
The SC contractor shall be responsible for notifying the experimenter of launch base requirements and identifying any incompatibilities that may exist. Resolving any conflicts will ultimately be the responsibility of the program office, but shall be worked cooperatively between the SPO, the experimenter, and the SC contractor.
The SC contractor shall provide a clean room facility (Class 100,000 or better) at the OSEM-to-SC integration site.
The SC contractor shall provide at his test site a means for mounting a GPS antenna outside the building at a site providing nearly unobstructed view of the sky, and a path for an experimenter provided cable to be laid from the mounted GPS antenna to the experimenter's test equipment.
The SC contractor shall provide the facilities, equipment, and personnel necessary to verify proper operation of the SC to experiment interface and support for experiment functional testing at the SC contractor's facility. Experiment checkout of RF equipment will require tests using direct GSE connection to antenna ports, radiated testing using antenna hats, and free radiation test. The test flow is expected to consist of the following:
1) Post ship functional testing (includes RF testing)
2) SC integration functional test (includes RF testing)
3) Pre-Environmental Integrated System Test (RF testing TBD)
4) Environmental Functional Testing (no RF testing, EMI?)
5) Post-Environmental Integrated System Test (RF testing TBD)
6) CGS and MEGS compatibility testing (an "end-to-end" test including RF testing)
7) Launch Base functional testing (includes RF testing)
Launch of the OSEM SC at this time carries no coordination constraint with any other event or activity.
No pre-launch trajectory parameter information is required by the experimenter.
OSEM shall be unpowered during ascent. Power is to be applied to the experiment only after achieving a stable orbit and successfully deploying any release mechanisms (to include PA uncaging).
The SC contractor shall be responsible for all operations during early-orbit checkout. Operations shall transition to the experimenter's responsibility after ensuring capability to perform mission (criteria TBD).
Data uploaded to or downloaded from the experiment using GCS1 (while located at the SC contractor's facility) will be transferred to the experimenter on magnetic media or through a dialup connection. Physical access to GCS1 shall be limited to essential contractor personnel only and use shall require a userid and password authentication. The experimenter will be responsible for retrieving data from GCS1 using the comm capabilities of GCS2 and shall also be able to remotely perform a low-level delete of experiment data residing on GCS1.
During integration and test, the experimenter requires a secure vault for the storage of computers, data, software, and documentation necessary for functional testing of the experiment. The vault shall be in accordance with DoD Regulation 5200.1 and Air Force Regulations 205-1 and 207-1. The vault shall be large enough too accommodate work areas for two people and contain a standard four drawer secure safe for storage of documentation, magnetic media, and other materials as necessary. The combination to the vault will be set by experimenter security personnel and revealed to the vault provider only after the end of test and removal of all experimenter equipment and materials. Controlled information required for OSEM testing shall be classified no higher than SECRET Collateral.
All data prepared for transmission to the SC, and SC data received through the TT&C channel, shall remain encrypted through all phases of an uplink or downlink transmission. The GCS shall be capable of performing the bulk encryption and decryption required for SC data. Only the experimenter shall have the ability to decrypt experiment data. The experimenter will assume all responsibility for encrypting experiment data uploads before delivery to a GCS.
The installation and operation of the GCS shall comply with all security requirements levied as a result of using NSA cryptography devices.
The following represents a conceptual schedule of data and hardware deliverables. The actual deliverable schedule and requirements for each deliverable shall be negotiated between the SC contractor and the experimenter with the government program office's approval.
Draft Experiment ICD Inputs (includes mechanical PDR - 30 days (TBD)
drawings, I/O schematics, data and command
formats, thermal models)
Draft Ground and Flight Operations Requirements PDR - 30 days (TBD)
Ground Station GFP List SCR - 30 days (TBD)
Final Experiment ICD Inputs CDR - 30 days (TBD)
Final Ground and Flight Operations Requirements CDR - 30 days (TBD)
Experiment Mass Model Delivery PDR + 30 days (TBD)
Initial Compliance Data Package Delivery - 45 days
(TBD)
Final Compliance Data Package Delivery - 14 days
(TBD)
Experiment Hardware Delivery ILC - 180 days (TBD)
TBD TBD
PDR TBD CDR TBD SC Interface/Databus Simulator (TBD) TBD TBD TBD
Figure A-1 PMDA Mechanical Interface (1)
Figure A-2 PMDA Mechanical Interface (2)
Figure A-3 PMDA Mechanical Interface (3)
Figure A-4 PEDA Mechanical Interface
Available Upon Request.
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