PHEOS PSRR

1. PHEOS PSRR PSRR Objectives: Show that all system requirements have been defined and are traceable to top level science objectives. Further, all requirements can either be met with the baseline design (or compliance issues have been identified).

2. PHEOS PSRRMission Systems and Requirements

3. Mission Systems

4. Instrument System • Physical Payload • Twin camera system • Electronics • Cabling Baseline design to be discussed this afternoon

5. Science Operations Centre Science Operations Centre is responsible for Primary Mission Management, this includes; • Interfacing with PCW Ground Systems • Command generation and telemetry processing • Raw (instrument) data processing (through Level 0) • Level 0 data relay to Science Data Centre • Mission operations (includes instrument health/safety and performance monitoring, payload performance trending, anomaly detection & resolution, procedure development, payload resource accounting, special operations planning) • Interface with engineers regarding trending results • Mission scheduling and planning • Image Registration monitoring operations (alignment) • Routine inflight instrument calibration support and Product Monitoring • Instrument raw data temporary storage (relay to SDC) • Spacecraft telemetry data archive and remote access to telemetry

6. Science Operations Centre Subsystems • Product Monitor (likely linked to SDC) • Automated display systems for Level 1B data produced by the SDC • Telemetry Monitor • Automated display (and alarm) systems for instrument health and safety data • Instrument Simulator • Enable verification of payload command structures and format • Flight operations procedure development and validation (routine and contingency) • End-To-End testing of procedures • Telemetry Data Archive • Provide open access to all instrument health data for trending analysis and engineering support • Temporary Archive • Staging of Level 0 data for SDC

7. Science Data Centre Science Data Centre is responsible for Data Product Management, this includes; • Interfacing with Science Operations Centre • Product Generation (Level 1b through Level 3) • Perform radiometric calibration and image correction • Integrate PCW satellite attitude and pointing information to product geographic reference grids for each image • Integration of images from both spacecraft • Maintain Calibration Database • Monitor Instrument Calibration • Analyze on-orbit calibration and contribute to calibration procedures and scheduling • Product Distribution • Maintain an open access data archive of all data products • Maintain targeted access for specific user groups (if required) • For example, customized rsync access or movie generation • Design and Maintain End User Software • For example, mapping programs based on standard PCW-UVI data products. These would be targeted to the scientific community to increase the usability of the PCW-UVI data • Respond to end user requests for data products and/or support • Copy data to an off-site backup (likely WestGrid)

8. Calibration and Characterization Calibration and Characterization System is responsible for; • Providing Sufficient Information to Enable the Generation of Data Products (Level 1b through Level 3) • Perform radiometric calibration • Flat field characterization • Point spread function characterization • Image distortion map • System filter response • Dark count characterization • Instrument Calibration and Characterization Procedure Development • Pre-flight • On-orbit • Development of Instrument Interface Software for Ground Calibration • Command and Control Sequences for On-Orbit Calibration Modes • Interface with SOC to test and validate procedures • Distribute Calibration Information to SOC and SDC

9. Requirement Flow

10. Traceability • There are no orphaned requirements. Each requirement is applicable to only one mission system. • Each MRD can be traced back to a Measurement Need in the Science Objectives and User Needs Document. In a lot of cases (particularly with the requirements on the instrument systems) we have had to use PCW information as well. For example, MN1. Global Auroral Images PCW CoO + CSA

11. Traceability For each MRD, we have included the Measurement/Data Need that it is derived from, the section of CDRL SC1 that discusses the topic, the Mission Objective that the MRD is applicable to, and the mission component to which applies.

12. Traceability • There are 10MRDs that are not derivable from the Science Objectives and User Needs Document. • ALL of these relate to extended imaging duration, data distribution, resource allocation, or product assurance requirements – none of which arediscussed in CDRL SC1. • Data distribution requirements are expected to evolve as the mission progresses, but we have included our intentions in the current MRD. • We are still investigating the conjugate imaging possibilities.... Since the orbit space is wide open, there are a lot of options.

13. Mission Requirements • Data Product Content and Levels • Image Attribute, Content and Quality Requirements • Imaging Operation Requirements • Spatial Coverage • Spatial and Temporal Resolution • Spectral Requirements • Extended Duration Imaging • Product Data Latency • Processing and Distribution • Archiving Requirements • Data Sharing and Ground Segment Considerations • Calibration, Validation and Characterization Requirements • Launch Window Requirements

14. Data Product Content and Levels

15. Data Product Content and Levels Data processing level designations are based on the Earth Observing Science Data Information System (EOSDIS) data definitions (see NASA’s Earth Observing Science Data Resource document for a more complete description).

16. Spatial Coverage MRD19. PCW-UVI shall provide data products for the contiguous Northern auroral zone between the geomagnetic latitudes of 45 (target of 40) and 90 degrees. PCW-UVI Area of Interest (AoI) Target  40-90o Geomagnetic Threshold  45-90o Geomagnetic 100% coverage, 24/7 The S/C pointing and orbit are the largest factor in attaining this.

17. Spatial Coverage The orbit space for PCW is wide open... We assumed that apogee would be maintained at a constant altitude over the Yellowknife meridian and that both S/C are in the same orbital plane.

18. Spatial Coverage

19. Image Attribute, Content and Quality Requirements • 20 degree field of view (MRD8), for both channels (MRD9) • Same image scene and resolution (MRD10) • Image distortion and PSF minimized (MRD11) • **Stray light minimized** (MRD12.1) with a solar exclusion angle of 25 degrees (MRD12.2) • Saturation limit of 30kR, and detection threshold of 20R (MRD13) • Dynamic range of 1500 (MRD14) • SNR of greater than 1 (target of 2) at detection threshold and lowest imaging frequency (MRD15) • MRDs 12,13,14 and 15 apply to all imaging conditions (including the sunlit portion of the Earth)

20. Spatial and Temporal Resolution MRD20. Image frames shall be acquired by UVI-IS at a minimum frequency of 0.05Hz (20 s images). MRD21. Image frames may be acquired at integration times from 1s to 60s. The nominal maximum integration time will be 19s, however the additional 41 s shall provide for margin. MRD22. Image frames shall be acquired with a minimum ground samplingdistance of 40 km at nadir (target of 30 km). MRD23. If sub-exposure (sub-images) are utilized it shall be possible to acquire sub-images with an integration time from 0.1 s to 60 s. The nominal sub-image integration time may be 0.1 s to provide maximum performance, however with reduced performance the instrument shall be able to acquire a sub-image with an integration time up to 60s. This provides margin to reduce or remove the use of subframes for image acquisition.

21. Spectral Requirements • MRD26. The instrument shall provide coverage over two adjacent spectral channels, and implemented as follows; • MRD26.1. The full width half maximum wavelength for LBH-S channel shall be 140 nm (+/- 2 nm) to 160 nm (+/- 2 nm) • MRD26.2. The full width half maximum wavelength for LBH-L channel shall be 160 nm (+/- 2 nm) to 180 nm (+/- 2 nm) • MRD26.3. The response of the system at wavelengths greater than 350 nm shall be 10E-10 of the maximum in-band response for the both image channels. • MRD26.5. The spectral overlap of the two channels should be minimized MRD27. UVI-IS shall acquire temporally synchronized LBH-S (140-160 nm) and LBH-L (160-180 nm) images. Synchronization shall occur to within at least 1% of the exposure time (for a nominal 20 s exposure, images will be synchronized to within 0.2 s).

22. Requirements on Mission Systems Calibration Systems MRD42.1. PCW-UVI shall be calibrated prior to launch. Calibration shall be sufficient to enable the target accuracy requirements in table 1. The allocation to the ground calibration process is 50% of the value in table 1 [TBC]. [Requirement coupled to MRD42.2] MRD43. UVI-IS shall be characterized prior to launch. At a minimum the following parameters shall be determined; spectral bandpass, system throughput, image field distortion, point spread function across the image field, and thermal response. MRD46. The PCW-UVI system should be capable of on-orbit calibration (for example, using stellar sources or low Earth orbit satellite underpasses).