The following parameters refer to the telescope design as specified for Phase C. Additional Phase C reference files are available at GSFC. These include the field-of-view layout, detector properties, distortions, Zernike decompositions of the PSFs, pupil masks, transmission/effective area per filter, and more. Additional Coronagraph Instrument parameters and data are also available.
These spacecraft/instrument parameters, which are to be used in simulations and in designing science projects, are tied to a regular project design schedule (see the link to parameters in earlier mission phases below). To ensure consistency within the community, these parameters are released here only after approval by the Roman Space Telescope Project Scientist.
List of Previous Spacecraft and Instrument Parameters.
| Name | Value | Unit | Description |
|---|---|---|---|
| Mission_Launch_Site | Cape Canaveral Air Force Station, Florida | Launch site | |
| Mission_Launch_Vehicle | Delta IV Heavy | Launch vehicle | |
| Spacecraft_Operating_Temperature | 298 | K | Operating temperature of the spacecraft |
| Spacecraft_Orbit_Type | Sun-Earth L2 | Type of spacecraft orbit |
| Name | Value | Unit | Description |
|---|---|---|---|
| Telescope_Jitter_Intermediate_Focus | < 14 | milliarcsec | Telescope jitter at intermediate focus per axis (rms) requirement |
| Telescope_Primary_Diameter | 2.37 | m | Diameter of the telescope primary mirror |
| Telescope_Central_Obscuration | 32 | % | Linear obscuration of the telescope entrance pupil (diameter ratio) |
| Name | Value | Unit | Description |
|---|---|---|---|
| WFI_Correlated_Noise | 5 | e- | WFI detector correlated noise floor |
| WFI_Dark_Current | < 0.015 | e-/s/pixel | WFI detector dark current per pixel (requirement) |
| WFI_Detector_Type | H4RG-10 | Detector type for WFI | |
| WFI_Field_Of_View_Effective | 0.281 | deg2 | WFI total effective field of view (ignoring gaps between detectors) |
| WFI_Field_Of_View_Total | 0.32 | deg2 | WFI total field of view (including gaps between detectors) |
| WFI_Focal_Ratio | 7.9 | WFI instrument and telescope's combined focal ratio | |
| WFI_Interpixel_Capacitance | 0.02 | WFI interpixel capacitance in each of the four neighboring pixels | |
| WFI_Number_Of_Active_Columns | 4088 | pixel | Number of active detector columns (also known as the number of pixels in the x-direction) in (the image section of) a detector |
| WFI_Jitter_Wavefront_Error | < 0.707 | nm | Telescope intermediate focus wavefront error jitter (requirement) |
| WFI_Pixel_Scale | 0.11 | arcsec | WFI detector pixel scale in arcseconds/pixel |
| WFI_Pixel_Size | 10 | 10-6 m | WFI wide-field channel pixel size in each dimension |
| WFI_PSF_Ellipticity | < 0.00047 | WFI point spread function ellipticity per 184 seconds at WFI focus | |
| WFI_Readout_Noise | < 20 | e- CDS | WFI detector pixel readout noise rms for correlated double sampling |
| WFI_Temperature | < 100 | K | WFI detector operating temperature |
| WFI_Number | 18 | Total number of scientific detectors in WFI |
| Name | Value | Unit | Description |
|---|
| Name | Value | Unit | Description |
|---|---|---|---|
| WFI_Grism_Dispersion | 1.04-1.14 | nm/pixel | WFI Grism dispersion, dependent mostly on the FPA Y value in degrees (Y axis is positive towards payload origin and FPA Y axis origin is between detectors 1 and 10) as -0.1945Y + 1.0764. |
| WFI_Grism_Spectral_Resolving_Power | 435-865 | WFI grism resolving power (2 pixel) |
| Name | Value | Unit | Description |
|---|
| Name | Value | Unit | Description |
|---|
| Name | Value | Unit | Description |
|---|---|---|---|
| CGI_Mode_Imaging_N | Narrow FoV imaging. Currently implemented as HLC coronagraph + Band 1 filter + imaging camera | ||
| CGI_Mode_Imaging_W | Wide FoV imaging. Currently implemented as SPC_A coronagraph + Band 4 filter + imaging camera | ||
| CGI_Mode_IFS | Integral Field Spectroscopy (IFS). Currently implemented as SPC_B coronagraph + Band 3 filter + IFS |
| Name | Value | Unit | Description |
|---|---|---|---|
| CGI_Coronagraph_HLC | HLC = Hybrid Lyot Coronagraph | ||
| CGI_Coronagraph_SPC_B | SPC_B = Shaped Pupil Coronagraph for small inner working angle in a `bowtie' shaped field of view | ||
| CGI_Coronagraph_SPC_A | SPC_A = Shaped Pupil Coronagraph for large outer working angle in an annular field of view | ||
| CGI_Coronagraph_Inner_Working_Angle_HLC | 3 | lambda/D | Inner radius of region of highest contrast |
| CGI_Coronagraph_Inner_Working_Angle_SPC_B | 3 | lambda/D | Inner radius of region of highest contrast |
| CGI_Coronagraph_Inner_Working_Angle_SPC_A | 6.5 | lambda/D | Inner radius of region of highest contrast |
| CGI_Coronagraph_Outer_Working_Angle_HLC | 9 | lambda/D | Outer radius of region of highest contrast |
| CGI_Coronagraph_Outer_Working_Angle_SPC_B | 9 | lambda/D | Outer radius of region of highest contrast |
| CGI_Coronagraph_Outer_Working_Angle_SPC_A | 20 | lambda/D | Outer radius of region of highest contrast |
| CGI_Coronagraph_Annular_Size_HLC | 360 | degrees | Suppression region annular extent |
| CGI_Coronagraph_Annular_Size_SPC_B | 130 | degrees | Suppression region annular extent |
| CGI_Coronagraph_Annular_Size_SPC_A | 360 | degrees | Suppression region annular extent |
| Name | Value | Unit | Description |
|---|---|---|---|
| CGI_Bandpass_Center1 | 575 | nm | Central wavelength for bandpass 1 |
| CGI_Bandpass_Width1 | 10.1 | % | Bandwidth (FWHM/lambda0 in %) for bandpass 1 |
| CGI_Bandpass_Min1 | 546 | nm | Minimum wavelength for bandpass 1 |
| CGI_Bandpass_Max1 | 604 | nm | Maximum wavelength for bandpass 1 |
| CGI_Bandpass_Center2 | 660 | nm | Central wavelength for bandpass 2 |
| CGI_Bandpass_Width2 | 18.2 | % | Bandwidth (FWHM/lambda0 in %) for bandpass 2 |
| CGI_Bandpass_Min2 | 600 | nm | Minimum wavelength for bandpass 2 |
| CGI_Bandpass_Max2 | 720 | nm | Maximum wavelength for bandpass 2 |
| CGI_Bandpass_Center3 | 760 | nm | Central wavelength for bandpass 3 |
| CGI_Bandpass_Width3 | 18 | % | Bandwidth (FWHM/lambda0 in %) for bandpass 3 |
| CGI_Bandpass_Min3 | 690 | nm | Minimum wavelength for bandpass 3 |
| CGI_Bandpass_Max3 | 830 | nm | Maximum wavelength for bandpass 3 |
| CGI_Bandpass_Center4 | 825 | nm | Central wavelength for bandpass 4 |
| CGI_Bandpass_Width4 | 9.9 | % | Bandwidth (FWHM/lambda0 in %) for bandpass 4 |
| CGI_Bandpass_Min4 | 784 | nm | Minimum wavelength for bandpass 4 |
| CGI_Bandpass_Max4 | 866 | nm | Maximum wavelength for bandpass 4 |
| CGI_Bandpass_ND | 10000 | Attenuation factor of Neutral Density filter used for target acquisition |
| Name | Value | Unit | Description |
|---|---|---|---|
| CGI_Bandpass_Engineering_Center1a | 555.7 | nm | Central wavelength for engineering filter 1a (WFSC), Wavefront Sensing and Control (WFSC) |
| CGI_Bandpass_Engineering_Width1a | 3.5 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 1a |
| CGI_Bandpass_Engineering_Center1b | 575 | nm | Central wavelength for engineering filter 1b (WFSC) |
| CGI_Bandpass_Engineering_Width1b | 3.4 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 1b |
| CGI_Bandpass_Engineering_Center1c | 594.3 | nm | Central wavelength for engineering filter 1c (WFSC) |
| CGI_Bandpass_Engineering_Width1c | 3.3 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 1c |
| CGI_Bandpass_Engineering_Center2a | 656.3 | nm | Central wavelength for engineering filter 2a (IFS calibration) |
| CGI_Bandpass_Engineering_Width2a | 1 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 2a |
| CGI_Bandpass_Engineering_Center3a | 710 | nm | Central wavelength engineering filter 3a (IFS calibration) |
| CGI_Bandpass_Engineering_Width3a | 1 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 3a |
| CGI_Bandpass_Engineering_Center4a | 797.7 | nm | Central wavelength for engineering filter 4a (WFSC) |
| CGI_Bandpass_Engineering_Width4a | 3.4 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 4a |
| CGI_Bandpass_Engineering_Center4b | 825 | nm | Central wavelength for engineering filter 4b (WFSC) |
| CGI_Bandpass_Engineering_Width4b | 3.3 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 4b |
| CGI_Bandpass_Engineering_Center4c | 852.3 | nm | Central wavelength for engineering filter 4c (WFSC) |
| CGI_Bandpass_Engineering_Width4c | 3.2 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 4c (WFSC) |
| CGI_Bandpass_Engineering_Center4d | 825 | nm | Central wavelength for engineering filter 4d (IFS calibration) |
| CGI_Bandpass_Engineering_Width4d | 1 | % | Bandwidth (FWHM/lambda0 in %) for engineering filter 4d |
| Name | Value | Unit | Description |
|---|---|---|---|
| CGI_Detector_Model | e2v CCD201-20 | Detector make and model | |
| CGI_Detector_Pixel_Number | 1024 | Number of CGI detector pixels in each dimension, both imaging and spectroscopy | |
| CGI_Detector_Pixel_Size | 13 | 10-6 m | Pixel size of CGI detector pixels in each dimension, both imaging and spectroscopy |
| CGI_Detector_Readnoise | 1.7x10-6 | e-/pixel/frame | Effective read noise when using the electron multiplying (EM) gain in photon counting mode |
| CGI_Detector_Saturation | 80000 | e- | CGI detector full well (EM gain dependent), assuming no EM gain applied. 80,000e- is the full well for a commercial device, the flight device will be a factor of several smaller depending on TBD channel width modifications |
| CGI_Detector_Dark_Current_BOL | 0.00014 | e-/pixel/s | CGI dark current for T = 168 K (beginning of life) |
| CGI_Detector_Dark_Current_EOL | 0.0007 | e-/pixel/s | CGI dark current for T = 168 K (end of life) |
| CGI_Detector_Clock_Induced_Charge_BOL | 0.025 | e-/pixel/frame | CGI clock-induced charge (beginning of life), 10 MHz horizontal frequency; 1 MHz vertical frequency; serial clock swing < 10 V |
| CGI_Detector_Clock_Induced_Charge_EOL | 0.03 | e-/pixel/frame | CGI clock-induced charge (end of life), 10 MHz horizontal frequency; 1 MHz vertical frequency; serial clock swing < 10 V |
| CGI_Detector_Detected_Quantum_Efficiency_Band1_BOL | 69 | % | CGI detector detected quantum efficiency in the center of Band 1, includes intrinsic QE, `reflection losses,' charge traps, cosmic ray contamination. Assumes flux levels commensurate with requirements (beginning of life) |
| CGI_Detector_Detected_Quantum_Efficiency_Band3_BOL | 39 | % | CGI detector detected quantum efficiency in the center of Band 3, includes intrinsic QE, `reflection losses,' charge traps, cosmic ray contamination. Assumes flux levels commensurate with requirements (beginning of life) |
| CGI_Detector_Detected_Quantum_Efficiency_Band4_BOL | 31 | % | CGI detector detected quantum efficiency in the center of Band 4, includes intrinsic QE, `reflection losses,' charge traps, cosmic ray contamination. Assumes flux levels commensurate with requirements (beginning of life) |
| CGI_Detector_Detected_Quantum_Efficiency_Band1_EOL | 57 | % | CGI detector detected quantum efficiency in the center of Band 1, includes intrinsic QE, `reflection losses,' charge traps, cosmic ray contamination. Assumes flux levels commensurate with requirements (end of life) |
| CGI_Detector_Detected_Quantum_Efficiency_Band3_EOL | 29 | % | CGI detector detected quantum efficiency in the center of Band 3, includes intrinsic QE, `reflection losses,' charge traps, cosmic ray contamination. Assumes flux levels commensurate with requirements (end of life) |
| CGI_Detector_Detected_Quantum_Efficiency_Band4_EOL | 25 | % | CGI detector detected quantum efficiency in the center of Band 4, includes intrinsic QE, `reflection losses,' charge traps, cosmic ray contamination. Assumes flux levels commensurate with requirements (end of life) |
| Name | Value | Unit | Description |
|---|---|---|---|
| CGI_Imaging_FoV | 9 | arcsec | Coronagraph imaging field-of-view diameter without coronagraph masks |
| CGI_Imaging_Pixel_Scale | 0.021 | arcsec/pixel | Coronagraph imaging pixel scale, Nyquist sampled (lambda/2D) at 500 nm |
| Name | Value | Unit | Description |
|---|
| Name | Value | Unit | Description |
|---|
| Name | Value | Unit | Description |
|---|---|---|---|
| CGI_Predicted_Performance_Throughput_Imaging_HLC | ≥ 0.013 | Planet core throughput in Band 1 HLC imaging mode, beginning of life. Planet core throughput = the fraction of planet light incident on the telescope that is encircled in the half-light contour of the final CGI PSF. Accounts for: 1) Geometric obscuration of the WFIRST pupil; 2) Core throughput losses due to diffraction from WFIRST pupil; 3) Reflection losses in the telescope optics; 4) Reflection & transmission losses inside CGI (exclusive of coronagraph masks); 5) Core throughput losses due to coronagraph masks. Does not account for: 1) polarizers; 2) detector effective QE; 3) Model Uncertainty Factors (i.e., MUF=1) | |
| CGI_Predicted_Performance_Throughput_Imaging_SPC_A | ≥ 0.011 | Planet core throughput in Band 4 SPC_A imaging mode, beginning of life. Same assumptions as for HLC throughput parameter. | |
| CGI_Predicted_Performance_Throughput_IFS_SPC_B | ≥ 0.008 | Planet core throughput in Band 3 SPC_B IFS mode, beginning of life. Same assumptions as for HLC throughput parameter | |
| CGI_Predicted_Performance_Imaging_Contrast_Pred | 6x10-10 | Predicted planet-to-star flux ratio for an SNR=5 imaging detection in band 1 with HLC, 100hr integration, after post-processing. This prediction is based on�modeling and error budgeting of Phase A WFIRST observatory and CGI, including: observatory and instrument stability during CGI con-ops, coronagraph starlight suppression performance, detector properties, and post-processing gains. Coronagraph and detector models have been validated against experimental results. Does not include model uncertainty factors on observatory or coronagraph performance (i.e., MUF=1) | |
| CGI_Predicted_Performance_IFS_Contrast_Pred | 2x10-9 | Predicted planet-to-star flux ratio for an SNR=5 spectrum in band 3 with SPC_B (bowtie), 100hr integration, after post-processing. This prediction is based on modeling and error budgeting of Phase A WFIRST observatory and CGI, including: observatory and instrument stability during CGI con-ops, coronagraph starlight suppression performance, detector properties, and post-processing gains. Coronagraph and detector models have been validated against experimental results. Does not include model uncertainty factors on observatory or coronagraph performance (i.e., MUF=1) |
| Name | Value | Unit | Description |
|---|