Table 9 MAJIS driving requirements and as-built performances at nominal temperature (OH ∼130 K). Comparison when possible with NIMS (Carlson et al. 1992) and JIRAM (Adriani et al. 2017a) are presented when possible and relevant

Spectral range (VISNIR)

0.5-2.35 μm

0.49-2.35 μm

After launch

0.7+ μm

2+ μm

Spectral range (IR)

2.25-5.54 μm

2.27-5.56 μm

After launch

Up to 5.2 μm

Up to 5 μm

Nominal spectral sampling (VISNIR)

≤ 3.65 nm ± 0.25

3.5-3.8 nm

Nominal case corresponding to 508 spectels (spectral element)

12.5/25 nm

10 nm

Nominal spectral sampling (IR)

≤ 6.50 nm ± 0.25

5.9-6.9 nm

Nominal case corresponding to 508 spectels

25 nm (10 nm for λ <1 μm)

10 nm

Spectral FWHM (VISNIR)

≤ 5.5 nm

2.9-4.6 nm

Depends on wavelengths. See Sect. 6.2

12.5 nm

Spectral FWHM (IR)

≤ 10 nm

5.5-7 nm

Depends on wavelengths. See Sect. 6.2

12.5 nm

Swath width

3.4°

3.4°

400 number of pixels across FOV

3.5°

Spatial sampling

150 μrad

150 μrad

e.g. 75 m/pix during the GCO500 orbit

500 μrad

240 μrad

Lifetime

>14 y

>14 y

Estimate based on heritage and degradation tests at sub-system levels

Optical header temperature

<140 K

∼126 K attainable

Operational temperature depending on trajectory

VISNIR detector temperature

<140 K

127 K attainable

Operational temperature depending on trajectory

IR detector temperature

<90 K

88 K attainable

Operational temperature depending on trajectory and operations

Pointing

±4° along track

±4° along track

Using the scan mirror. Larger angle exploration is possible for ICU pointing (8.5°). 1 step is equal to 0.003139° (optical angle) so that a motion of 3 steps corresponds to 1.0957 IFOV

Scan mechanism compensation

Up to 5.1 km/s

Compliant

GCO200 science case

Spectral smile (VISNIR)

≤ 3.65 nm

≤ 2.1 nm

2D smile

Keystone (VISNIR)

≤ 1 IFOV

≤ 1 IFOV

Spectral smile (IR)

≤ 6.50 nm ± 0.60 nm

≤ 3.1 nm

Limited spectral data

Keystone (IR)

≤ 1 IFOV

≤ 1 IFOV

Expected out-of-field straylight

<2%

Out-of-field straylight below 1300 nm

Partly mitigated by subtraction of the background (shutter closed signal)

Expected in-field straylight

<10⁻⁴

Not compliant for VISNIR channel Compliant for IR

See Sects. 6.4 and 6.5

Total Ionizing Dose (TID):

Passive despiking (shielding + spot shielding)

- Optical elements

<100 to 500 krad

<100 to 500 krad

- Electronic components

<50 krad

- Detectors

<80 krad

<80 krad

Spikes resulting from high energy electron impact

At most 1% of impacted pixels after filtering

Compliant

Active on-board despiking; see Sect. 5.3.1

SNR (icy satellites)

>100 for λ < 2.8 μm

>30 in 3.2-3.6 μm

>20 for λ > 3.6 μm

Compliant, except for the 0.6-0.7 μm range that may be impacted by a spectrally structured straylight component

See Sects. 6.4 and 6.5

SNR (Jupiter)

>100 for almost all wavelengths, methane absorption excluded

>10 for aurora

Compliant, except for the 0.6-0.7 μm range that may be impacted by a spectrally structured straylight component

See Sects. 6.4 and 6.5