1. JEM-SMILES Instrumental Capabilities
Junji INATANI
Space Utilization Research Program
NASDA
Feb. 21, 2001, Kyoto
JEM-SMILES

2. “Mission Plan” Chapter 3
Introduction
ISS and JEM
SMILES Payload
Field of View (FOV)
Altitude Scanning of the Antenna
Global Coverage
Interference with FOV
Antenna Response Pattern
ISS Orbit and Attitude Variations
Tangent Height Calibration
Spectral Regions and Sensitivity
Observation Frequency Bands
Frequency Down-conversion
Acousto-optic Spectrometer
Sensitivity
Brightness Temperature Calibration
Conclusion
Feb. 21, 2001, Kyoto
JEM-SMILES

3. Introduction
ISS and JEM
SMILES
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JEM-SMILES

4. Japanese Experiment Module: “KIBO”
SMILES
Feb. 21, 2001, Kyoto
JEM-SMILES

5. Instruments
SMILES:
Superconducting Submillimeter-wave Limb-emission Sounder
View in the Cryostat
Feb. 21, 2001, Kyoto
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6. Signal Flow
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JEM-SMILES

7. Receiver Sensitivity: SIS vs SBD
SBD mixer receiver
SIS mixer receiver
hf/k: Quantum Limit
Superconductive SIS mixer receivers have some 20 times higher sensitivity than conventional Schottky-diode mixer receivers for frequencies less than 700 GHz.
Feb. 21, 2001, Kyoto
JEM-SMILES

8. Inside the SIS Mixer Mount Developed by NASDA in-house activity.
640 GHz SIS Mixer
Inside the SIS Mixer Mount
Developed by NASDA in-house activity.
0.4 mm
Nb/AlOx/Nb Mixer Device
Fabricated at NAOJ, Nobeyama
Feb. 21, 2001, Kyoto
JEM-SMILES

9. Cryostat Radiation Shield: MLI (40 layers)
Signal Input Window: IR Filters (‘Zitex’)
Support for 100 K Stage: S2-GFRP Straps (12 pieces)
Support for 20 K Stage: GFRP Pipes (4 pieces)
Support for 4 K Stage: CFRP Pipes (4 pieces)
Feb. 21, 2001, Kyoto
JEM-SMILES

10. 4 K Mechanical Cooler Cooling to 100 K & 20 K:
Cooling Capacity:
20 mW @ 4.5 K K K
Power Consumption:
300 W @ 120 VDC
Mass:
Cooler 40 kg
Cryostat 26 kg
Electronics 24 kg
Total 90 kg
Cooling to 100 K & 20 K:
Two-stage Stirling Cooler
Cooling to 4.5 K:
Joule-Thomson Cooler
Feb. 21, 2001, Kyoto
JEM-SMILES

11. Mechanical Components of Coolers
Cold-head and Compressor for Two-stage Stirling Cooler
Two Compressors for Joule-Thomson Cooler
Feb. 21, 2001, Kyoto
JEM-SMILES

12. Sub-mm Receiver Subsystem
To Antenna
Ambient Temperature Optics
AOPT
Cryostat
To Cold-Sky
Terminator
AAMP
Single Sideband
Filter
CREC
Sub-mm
LO Source
He Compressor (JT)
He Compressor (ST)
Feb. 21, 2001, Kyoto
JEM-SMILES

13. Acousto-Optical Spectrometer
Bandwidth:
1200 MHz x 2 units
IF: GHz / unit
Focal Plane:
1728-ch. CCD array x 2 units
Frequency Resolution:
1.8 MHz (FWHM)
Channel Separation: 0.8 MHz / ch.
AD Conversion:
12-bit, 2-CCD readouts
in 4.9 msec
Adder Output:
16 bits x 1728 ch. x 2 units
in 500 msec
AOS (Astrium & OPM)
Feb. 21, 2001, Kyoto
JEM-SMILES

14. Field of View (FOV) Altitude Scanning of the Antenna Global Coverage
Interference with FOV
Antenna Response Pattern
ISS Orbit and Attitude Variations
Tangent Height Calibration
Feb. 21, 2001, Kyoto
JEM-SMILES

15. Atmosphere Scanning
A single spectral profile is acquired in every 0.5 sec, in which the antenna moves deg in six angular steps.
Feb. 21, 2001, Kyoto
JEM-SMILES

16. Antenna Response Pattern
Effective Pattern:
Integrated over AZ angles
Averaged for six consecutive EL points involved in a unit data
Feb. 21, 2001, Kyoto
JEM-SMILES

17. Height Resolution (Antenna)
Angular Width
(or Interval)
[deg]
Linear Width (or Interval)
at Tangent Point Heights: 10 – 60 km
[km]
ISS: 350 km
ISS: 400 km
ISS: 460 km
HPBW
0.096
3.82
– 3.24
4.08
– 3.51
4.41
– 3.82
Sampling Interval
2.25
– 1.92
2.42
– 2.10
2.60
– 2.26
A refraction effect is included, which is significant for TPH < 20 km.
Feb. 21, 2001, Kyoto
JEM-SMILES

18. Global Coverage Trajectory for 24 Hours The Arctic Region
Covered Latitudes:
68N – 35S (ISS Yaw: +15 deg)
65N – 38S (ISS Yaw: 0 deg)
61N – 42S (ISS Yaw: -15 deg)
Horizontal Sampling Interval:
about 360 km in orbital direction
Feb. 21, 2001, Kyoto
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19. Direction of Line-of-sight
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20. FOV Interference Blue: with Main Beam by Solar Paddle
Orange: with CST by SUN
Red: with Main Beam by SUN
FOV Interference
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21. ISS Orbit
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22. ISS Attitude
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23. How to Determine Tangent Point Height
HCS: Heliocentric Coordinate System
GCS: Geocentric Coordinate System
Feb. 21, 2001, Kyoto
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24. Errors in Tangent Point Height (1-s level)
Causes of Errors
Bias [km]
Random [km]
Errors in Attitude:
Sub-mm beam offset errors
5.02 -
Mechanical driving errors
0.27
Thermal bending errors
0.12
Mechanical alignment errors
STT measurement errors
0.06
Time synchronization errors
0.50
0.18
Errors in Altitude:
ISS positional errors
0.30
0.10
Overall Error with the beam offset
5.07
0.34
Overall Error w/o the beam offset
0.76
Feb. 21, 2001, Kyoto
JEM-SMILES

25. Spectral Regions and Sensitivity
Observation Frequency Bands
Frequency Down-conversion
Acousto-optic Spectrometer
Sensitivity
Brightness Temperature Calibration
Feb. 21, 2001, Kyoto
JEM-SMILES

26. Expected Spectra: Band-A
Limb Scanning A
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27. Expected Spectra: Band-B
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28. Expected Spectra: Band-C
Limb Scanning C
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29. Frequency Down-conversion
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30. Single Sideband Filter
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31. Effect of Image Band (1)
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32. Effect of Image Band (2)
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33. AOS: Differential Non-linearity
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34. Standing Waves
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35. Expected Sensitivity
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36. Sensitivity and Accuracy
Causes
Sensitivity
Accuracy of
Absolute Brightness
Excess Brightness
Radiometric Noise
Gain Variation
Gain Non-linearity
Standing Waves
DNL* in AOS
Knowledge Errors**
* Differential non-linearity of the A/D converter.
** Concerning antenna characteristics and temperature measurement errors.
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37. Accuracy of Absolute Brightness Temp.
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38. Conclusions (1)
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39. Conclusions (2)
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40. Conclusions (3)
Feb. 21, 2001, Kyoto
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