1. WFIRST Instrument reference information July 1, 2015

2. The information in this file is excerpted from the SDT report dated March 10, 2015 (Spergel et al. arXiv:1503.03757) and from the February 13, 2015 SDT briefing to Paul Hertz. Both are accessible from the WFIRST site: http://wfirst.gsfc.nasa.gov http://wfirst.gsfc.nasa.gov Extensive information on WFI optical characteristics is available herehere

3. WFIRST-AFTA Observatory Concept Key Features Telescope: 2.4m aperture primary Instruments – Wide Field Imager/Spectrometer & Integral Field Unit – Internal Coronagraph with Integral Field Spectrometer Overall Dry Mass: ~4060 kg (CBE) Structure: high stiffness composites; modular packaging for avionics GN&C/Propulsion: inertial pointing, 3-axis stabilized, mono-prop system for stationkeeping & momentum unloading Data Downlink Rate: Continuous ~600 Mbps Ka- band to dedicated ground station C&DH: low rate bus for housekeeping and spacecraft control, high speed bus for science data Power: ~2400 W average power (CBE) GEO orbit Launch Vehicle: Delta IV Heavy GSFC: leads mission, wide field instrument, spacecraft JPL: leads telescope, coronagraph 3 02-13-15 WFIRST-AFTA SDT Final Report Briefing to Hertz

4. WFIRST-AFTA Payload Layout 4 02-13-15WFIRST-AFTA SDT Final Report Briefing to Hertz Wide Field Instrument Coronagraph Instrument Instrument Carrier

5. WFIRST-AFTA Payload Optical Block Diagram 5 02-13-15WFIRST-AFTA SDT Final Report Briefing to Hertz

6. Optical Field Layout The Wide Field Instrument (WFI) has two science channels – A Wide Field Channel (WFC) with two modes dependent on element wheel position Wide Field Imaging Mode (WIM) Wide Field Spectroscopy Mode (WSM) – An Integral Field Unit (IFU) channel viewing two fields 3”x3.15” and 6x6.3” FOVs The Coronagraph Instrument (CGI) is a small field system in a separate field of view – Contains an imager and a Integral Field Spectrometer (IFS) viewing the same field 6 02-13-15 WFIRST-AFTA SDT Final Report Briefing to Hertz Channel Field Layout for WFIRST-AFTA Instruments

7. Telescope Reuse 7 02-13-15WFIRST-AFTA SDT Final Report Briefing to Hertz

8. Wide Field Instrument Overview Key Features Wide field channel instrument for both imaging and spectroscopy – 3 mirrors, 1 powered – 18 4k x 4k HgCdTe detectors cover 0.76 - 2.0  m – 0.11 arc-sec plate scale – Single element wheel for filters and grism – Grism used for GRS survey covers 1.35 – 1.89  m with R = 461 (~620 – 870) IFU channel for SNe spectra, single HgCdTe detector covers 0.6 – 2.0  m with R between 80-120 8 02-13-15 WFIRST-AFTA SDT Final Report Briefing to Hertz Focal Plane Assembly Optical Bench Cold Electronics Cold Optics Radiation Shield Element Wheel

9. WFI Filters

10. WFI detector performance Detector technology development requirements. The right two columns summarize the results from the two lots of prototype detectors available in late 2014.

11. IFU Layout - Slicer 11

12. IFU Layout – Relay to Spectrum 12

13. Coronagraph Instrument Overview 13 02-13-15WFIRST-AFTA SDT Final Report Briefing to Hertz Temperature293 K for instrument Temperature~165 K for cameras Data Volume~30 Gbits/day Imaging0.43 – 0.97 microns, 4.8" FoV 0.009" pixel scale, 1K×1K EMCCD Integral Field Spectrograph 0.60 – 0.97 microns R~70

14. Primary Architecture: Occulting Mask Coronagraph = Shaped Pupil + Hybrid Lyot 14 02-13-15WFIRST-AFTA SDT Final Report Briefing to Hertz SP and HL masks share very similar optical layouts Small increase in overall complexity compared with single mask implementation In “SP mode” provides the simplest design, lowest risk, easiest technology maturation, most benign set of requirements on the spacecraft and “use- as-is” telescope. This translates to low cost/schedule risk which is critical for the independent CATE process. In “HL mode”, affords the potential for greater science, taking advantage of good thermal stability in GEO and low telescope jitter for more planet detections in a shorter time

15. Model contrast performance Model-predicted contrast for the HLC in the presence of LOS jitter. Jitter values represent the variation after control by the LOWFS, which is expected to reduce rms jitter to a fraction of a milli-arcsecond. Model-predicted contrast for the SPC in the presence of LOS jitter. The LOWFS is expected to reduce jitter seen by the coronagraph to a fraction of a milli- arcsecond.

16. CGI Filters Coronagraph mask/filter sets for each configuration. The table shows the number of masks or filters required in each configuration at leach location in the optical beamtrain. Bandpass filters for planet imaging, spectroscopy, and dust debris disk imaging.

17. CGI IFS specifications

18. CGI Detector Performance Requirements 18 02-13-15WFIRST-AFTA SDT Final Report Briefing to Hertz Specification Expected Value RequirementUnitNotes Active Pixels1024 x 1024 --- Pixel Pitch13 x 13 micronsEffective area: 177.2mm 2 Effective Read Noise0.2 e-Achieved using EM gain Saturation Signal per Pixel50863N/Ae- EM amp full well @ 1 MHz vertical frequency Dark Current9 x 10 -5 1 x 10 -4 e-/pix/sec Temp 165K, inverted mode operation Clock-Induced Charge (CIC) @ 5  0.00130.0018e-/pix/frame 10 MHz horizontal frequency; 1 MHz vertical frequency; EM gain = 1000 QE at 660, 770, 890 nm88, 68, 28 %At 165K

19. Comm – Continuous downlink to dedicated ground station, same concept as SDO – S-band omni antennas for uplink and housekeeping data downlink – Ka-band for science data is ~600 Mbps GSFC developed transmitter (update of SDO design) with a capability of 1.2 Gbps (prototype on schedule for completion in early 2015) Attitude Control/Prop – 3-axis stabilized using 4 reaction wheels with thruster unloading – 14 mas drift & 14 mas jitter, RMS/axis – FGS uses guide window data from wide field focal plane – Mono-prop system for station-keeping, momentum unloading and end of life disposal Spacecraft Overview 19 02-13-15WFIRST-AFTA SDT Final Report Briefing to Hertz