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Proposed US Contribution to the Wide Field Imager. PSU MIT JHU. History. PSU, MIT, and SAO approached about four years ago to contribute to IXO WFI instrument. Proposed US contribution to IXO WFI was in the ICU hardware and software.
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Proposed US Contribution to the Wide Field Imager PSU MIT JHU
History • PSU, MIT, and SAO approached about four years ago to contribute to IXO WFI instrument. • Proposed US contribution to IXO WFI was in the ICU hardware and software. • This provided a clean interface between US and European hardware. • Drew upon decades of combined US experience with X-ray imaging instruments • Murray/SAO-JHU: Einstein HRI, ROSAT HRI, Chandra HRC • Bautz/MIT: ASCA SIS, Chandra ACIS, Suzaku XIS, Astro-H SXI • Burrows/PSU: Chandra ACIS, Swift XRT
US Response to L2 • Paul Hertz (director of NASA’s Astrophysics Division) has expressed interest in contributing to an L2 mission at a level of up to $150M. • The US X-Ray Science Interest Group (XRSIG) prepared a list of possible US contributions to ESA’s L2 mission for Paul’s consideration. This list included a US contribution to the ATHENA WFI instrument along the lines of the IXO contribution. • ESA Call for L2 Mission Concept proposals clearly permits US contributions to Instrument Teams
The current WFI architecture is similar to the IXO WFI architecture as of summer 2010 ? 2048 x 2816 pixels total, read out every 2 μs (?) => 1 Gpix/s – 1.5 Gpix/s High speed fiber optic data link proposed
Proposed US contribution to WFI US contribution Movable Instrument Platform ? • US contribution: ICU • Provides clean interface between US and European responsibilities • Capitalizes on initial development of high-speed event recognition • Propose fiber optic data transfer bus to WFI
Instrument Control Unit (ICU) Concept Based on IXO WFI / June 2010
Fiber Optic interface • Assumed 8 optical fibers (for IXO/WFI) • Mass < 500 g • Power < 3W • Cost ~ $70K • Double numbers for redundancy • Requires use of Xilinx FPGAs to interface to optical fiber transceivers • Xilinx Virtex-5QV FPGAs are rad-hard, 1 Mrad dose • Virtex-5 are fast enough, >3 GHz multi-gigabit serial
Spacecraft Com GSE connection Power Science Data Housekeeping Data Slow Control Bus ICU Block Diagram IXO WFI Instrument Control Unit Block Diagram June 2010 D. Burrows S/C Power Power Supply Board 1 PPS Instrument Processor Board (128K PROM, 512K EEPROM, 4MB SRAM, 512MB SDRAM) Slow Control (Spacewire) Spacewire Comm / Mem Board (512 MB Flash) Spacecraft Frame Builder 1 Custom FPGA / SRAM Fiber Optic Cables from HPPs Frame Builder 2 Custom FPGA / SRAM Housekeeping / Relays / Mechanisms To Filter Wheel Stepper Motor ASIC Substrate Power To APS Htr To HPP (x2) +1.7V ASIC Power +3.3V Digital Power
ICU Concept (8 slot version) 23.2 cm 23.2 cm 29.5 cm 2.5 mm
ICU Concept • 2.5mm Al chassis for shielding (5 kg) • 3U/6U box, 6 slot backplane (488 g) • Slot 0: LVPS (500 g, 11.25 W @ 70%) • Slot 1: 3U System Slot, Instrument Processor Board (450 g, 3.55 W) • Instrument control, telemetry formatting • Slot 2: 6U Comm/Memory Board (880 g, 3.55 W) • Slot 3: 6U Frame Builder Board 1 (880 g, 6.25 W) • Slot 4: 6U Frame Builder Board 2 (880 g, 6.25 W) • Slot 5: 6U HK / Relay / Mechanism Board (880 g, 6.50 W) • Slot 6: spare • Total mass: ~ 10.0 kg • Total power: 37.4 W
ICU Concept • Mass (IXO PDD allocation is 26.5 kg, w/ redundancy): • Total mass: 10.0 kg (CBE) • Total redundant mass: 25.9 kg (CBE+30%) • Power: • ICU Power: 37.4 W (CBE) • Total + 20%: 44.9 W (CBE + 20%)
Summary • PSU, MIT, and JHU are excited to have a chance to contribute to this mission! • Interested in ICU: • Power, mechanism control • Frame builder and telemetry formatting • Hardware and software • Joint development by PSU, MIT, JHU • Note that we also have experience in large thin filters for Chandra (HRC and ACIS)
Backup Slides Based on IXO WFI / June 2010
Proposed US Contribution to WFI • Based on IXO WFI instrument teaming arrangements • Proposed US contribution: frame builder and event processing software • PSU: provide high-speed digital framework, high-speed fiber interface to FEE • JHU: frame builder (event recognition) • MIT: flight software (event processing) • Builds on decades of combined experience in X-ray imaging instruments, including • Murray/SAO-JHU: Einstein HRI, ROSAT HRI, Chandra HRC • Bautz/MIT: ASCA SIS, Chandra ACIS, Suzaku XIS, • Burrows/PSU: Chandra ACIS, Swift XRT
Fiber Optic interface to ICU www.spacephotonics.com
Fiber Optic interface to ICU Design flexibility, good radiation tolerance, high speed, low power www.spacephotonics.com
WFI baseline FEE ASIC Power Image Controller / APS Sequencer CAMERA ADC Flex cable Flex cable ADC Sensor Power FPGA ADC FPGA ADC FPGA FPGA UL JHU PSU MIT ICU Power Conditioning Instrument Control Controller Power Processor Power CPU H/K Heater Power/Control Frame Builder mechanism controls S/C I/F Software Slow Control/Config
WFI ICU • CPU = Brain + Slow control • PSB: low voltage power supplies • S/C Interface (SpaceWire?) • Camera Interface (serial optical + SpaceWire?) • HK: all HK from outside the ICU will be digitized locally and provided to ICU on the slow control bus • Heater power / mechanisms • Detector temperature control • Filter stepper motor (if needed) • any other heaters or mechanisms • Frame Builder (JHU) • Frame buffer • Event recognition and formatter • System Software (PSU/SwRI) • O/S, drivers, S/C interface, heater control, ... • Science Software (MIT/JHU) • + Fully Redundant B-side
Issues/Questions • Power Conditioning in ICU box: • Controller power (3.3V for Brain, HK, slow control): • Commandable (by ICU) • control via solid-state switches to 2 HPPs • Processor power (Frame Builder) • Operating power for filter wheel: Commandable • Stepper controller in ICU, directly power filter wheel stepper motor • Heater power for APS heaters: Adjustable in ICU – analog power • need to sense temperature, control heater power to maintain constant temperature to within 0.1K • ASIC power • Analog supply voltages (~ 3-5V for AFE/CFE ASICS): Commandable (by ICU) • +/- supply for ASICs (1.7V), 3.3V for switcher, substrate voltage for switcher ASIC • control via solid-state switches, with separate switches for 2 HPPs
Issues/Questions • Housekeeping: • “All voltage channels can be read back via slow control for housekeeping purposes” • Does ICU get analog or digital HK from remote boxes? Yes • “All currents can be monitored by housekeeping” • Does this include currents generated in remote boxes? Yes • Heaters: • APS temperature control – we supply controlled analog voltage – must keep temperature variation < 0.1 K
Issues/Questions • Slow control: • resides in ICU • is it a digital communications link to smart remote ports? • Yes • “The slow control configures the entire system via a relatively slow serial link. It also commands switching of power supplies for the respective operating modes.”