PARAMETER VALUE Wavelength range 0.6 µm – 5.0 µm When operating in R = 1000 and R = 2700 mode, split in three spectral bands: 1.0 µm – 1.8 µm Band I 1.7 µm – 3.0 µm Band II 2.9 µm – 5.0 µm Band III Field of View 3 × 3 arcmin Spectral resolution R = 100 (MOS) R = 1000 (MOS + fixed Slits) R = 2700 (fixed Slits + IFU) Number of commendable open/ closed spectrometer slits MEMS technology based on micro-shutter arrays with 4 times 365 × 171 = 250 000 individual shutters, each of them with a size of 80 µm × 180 µm Detector 2 MCT Sensor Chip Assemblies (SCA's) of 2048 × 2048 pixels each. Pixel pitch = 18 µm × 18 µm Wavefront Error, including Telescope Diffraction limited at 2.45 µm at MSA: WFE = 185 nm RMS (Strehl = 0.80) Diffraction limited at 3.17 µm at FPA: WFE = 238 nm RMS (Strehl = 0.80) Limiting sensitivity * In R = 1000 mode, using one single 200 mas wide shutter or fixed slit, NIRSpec will be capable of measuring the flux in an unresolved emission line of 5.2×10−22 Wm−2 from a point source at an observed wavelength of 2 µm at SNR = 10 per resolution element in a total exposure of 105 s or less * In R = 100 mode, using one single 200 mas wide shutter or fixed slit, NIRSpec will be capable of measuring the continuum flux of 1.2×10−33 Wm−2Hz−1 from a point source at an observed wavelength of 3 µm at SNR = 10 per resolution element in a total exposure of 104 s or less NIRSpec optics envelope Approximately 1900 mm × 1400 mm × 700 mm Instrument mass 195 kg (430 lb) with about 100 kg silicon carbide parts, Electronic boxes: 30.5 kg (67 lb) Operating temperature 38 K (−235.2 °C; −391.3 °F)