1. Introduction to SMILES
Mission Objectives
Space Demonstration of Submillimeter Sensor Technology based on a Superconduvtive Mixer and 4-K Mechanical Cooler
Experiments of Submillimeter Limb-Emission Sounding of the Atmosphere
Global Observations of Trace Gases in the Stratosphere and Contribution to the Atmospheric Sciences

2. Scientific Objectives
Understanding global mechanism of ozone depletion
Overall chemical processes:
=> Multi-species observations
Global dynamics & Regional interactions:
=> Global 3-D observations
Advantages of SMILES
High sensitivity:
=> Real-time map without spatial averaging
Fine spectroscopy:
=> High detectability for minor weak species

3. Limb Sounding from ISS

4. Molecular Emissions: LSB
Band-1: GHz
Band-2: GHz
Band-1:
O3, H37Cl, HNO3, BrO
Band-2:
O3, H35Cl, HO2

5. Molecular Emissions: USB
Band-3: GHz
Band-3:
ClO, HO2, O3, BrO,
O3-isotopes

6. Global Mapping Trajectory of Tangent Points in 24 Hours
Latitudes Coverage: 65 N to 38 S
Trajectory of Tangent Points in 24 Hours
Distribution of atmospheric regions sampled in consecutive frames of antenna scanning. Length of each frame is 53 sec.

7. Signal Flow in SMILES Submm Signal is down-converted:
=> GHz => GHz
Emission-line Spectra are derived by AOS (Acousto-optic Spectrometer).

8. View of SMILES Alignment Panel ADE EPS SJTD AOPT AOS CST Cryostat STT
DPC
ANT

9. Submillimeter Receiver
Key Technology
Superconductivity Electronics (SIS mixer)
Cryogenic LNA Technology (HEMT amplifiers)
Submillimeter Devices & Components
Submillimeter Quasi-optics
Cryostat Technology (4K level)
Mechanical Cryo-cooler Technology (4k level)

10. 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.

11. 640 GHz SIS Mixer Nb/AlOx/Nb Device 1.2 um x 1.2 um, 5.5 kA/cm2
Fabricated at
Nobeyama Radio Observatory

12. Cooled HEMT Amplifiers
20K-stage Amplifier
100K-stage　Amplifier
Tphys = 300K
Vd = 2V, Id = 10mA
Tphys = 300K
Vd = 2V, Id = 10mA
Tphys = 100K
Vd = 1V, Id = 5mA
Tphys = 20K
Vd = 1V, Id = 5mA
Two HEMT Devices: FHX76LP
Gain:
23-26
Three HEMT Devices: FHX76LP
Gain:
30-33
Nitsuki Ltd.

13. Submillimeter LO Source
BBM by RPG/Ominisys
Gunn Phase Noise:
< -90 1MHz
Submm Freq. Stability:
1 x 10^(-8) /deg

14. Receiver Optics < Two Functions > - RF/LO Coupling
Ambient -Temperature Optics
< Two Functions >
- RF/LO Coupling
- Sideband Separation
Cooled Optics

15. SSB Filter with FSP’s
Single Sideband Filter: To separate USB and LSB signals
Frequency-Selective Polarizer:
Suitable for a fixed-frequency application
Extremely low reflection --- Low standing waves
SSB Filter (BBM) by
Thomas Keating Ltd.

16. SRX Subsystem To Antenna To Cold-Sky Terminator Single Sideband Filter
Ambient Temperature Optics
Cryostat
AOPT
To Cold-Sky
Terminator
AAMP
Single Sideband
Filter
Sub-mm
LO Source
CREC
He Compressor (JT)
He Compressor (ST)

17. Thermal Design of SMILES
Requirements
State-of-the-art cryogenic design is needed to keep SIS mixers at 4.5 K, HEMT amplifiers at 20 K /100 K.
Ambient-temperature Thermal Design is based on the Use of Coolant (FC-72)
Detail Analysis is Needed on Influences of Radiation Coupling to Space
High Temperature Stability is Needed for the Stable Operation of the Receiver

18. Cryogenics Requirements Mechanical Cooler
SIS Mixers & Cooled Optics @ 4.5 K
HEMT Amplifiers @ 20 K & 100 K
Mechanical Cooler
Cooling Method: Two-Stage Stirling & Joule-Thomson
Cooling Capacity: K K K
Power Consumption: 210 W (Coolers) + 90 W (Loss in PS)

19. 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)

20. Thermal Design of Cryostat
Window: Heat flow is reduced with two IR filters
IF cables: CuNi coaxial cables
HEMT current: Circuit is optimized for a Starved Bias Condition
JT load: Minimized by reducing the rate of GHe flow

21. Two-stage Stirling Cooler

22. Joule-Thomson Cooler Cryostat (inc. ST Cold Head): 29 kg
Stirling Compressor: 10 kg
JT Compressors (2 units): 15 kg
GHe Piping: 7 kg
Control & Drivers: 23 kg

23. Flow of Coolant FC-72 I/F Conditions: IN: 16-24 C, OUT: 16-50 C
Cryo-cooler (STC, CRST, JTC) and AOS need to be cooled at less than 30 C.

24. Concept of Thermal Control
Toyohashi, Jan. 6-7, 2000
Concept of Thermal Control
Radiation coupling to space occurs through HCAM, FRGF and Antenna.
This effect should be connected with the analysis for the coolant.

25. SMILES Output Data H/K and Attitude Data: 1553B
Spectroscopic Data: Ethernet
Data Rate: 120 kbps, continuous
No Mass Data Storage installed in SMILES.
Spectroscopic Data down-link to NASDA/TKSC will be
established through JEM/ICS link (via DRTS).
ICS: Inter-orbit Communication System
DRTS:Data Relay Test Satellite

26. SMILES on-orbit Data Processing
To JEM (PDH, PEHG)
Ethernet(10Base-T)
1553B
100 kbps
20 kbps

27. SMILES Observation Profile
Limb emission spectrum is measured every 500 ms
Limb scan is finished in 53 sec.
Main Antenna 6
Altitude coverage between 0 and 60km is guaranteed
Hot Load
for reference 4
Relative scan angle (degree) 2
Cold Sky
for reference
Switching mirror 30 10 20 30 40 50 60
Time (s)
Antenna scan profile

28. SMILES Radio 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)
cf. 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
Acousto-Optic Spectrometer
(Astrium & OPM)

29. Data Processing and Products
Toyohashi, Jan. 6-7, 2000
Data Processing and Products
Bit Stream
~ 120 kbps
Raw Data
Level_0 Data
Level_1 Data
Level_2 Data
Level_3 Data
Overlap Correction,
Time Sequence Rearrange
Edited Data
~ 1.24 GB/day
Radiometric Calibration etc.
Engineering Data
(Brightness Temp.)
~ 2.5 GB/day
Retrieval
Height Profiles
along Orbit
~ 170 MB/day
Averaging and Gridding
Global Map

30. Ground Data Processing
ISS
Ground Data　Processing
DRTS
NASDA/
TKSC
Raw Data
NASDA/TKSC
CRL
Level_0
Level_0
Univ.
Bremen
Level_1
Level_1
Level_1
Level_2
Level_2
Level_2
Level_3B
NASDA/
EORC
Level_3
Level_2
WWW
WWW
Anonymous Users
Level_3A
ftp, WWW
ftp, WWW
Registered Users

31. SMILES Level-2 Data Expected
Estimated Error
Example : Altitude profile of ClO volume-mixing-ratio

32. Concerns in SMILES Data Down Link
SMILES Mission Requirements:
Nominal data rate kbps
Continuous observation
No necessity for real time link
Effective Bandwidth of Ethernet in JEM is limited .
JEM/ICS link is yet to be improved to cover our mission requirements.

33. ISS Environmental Issues
Compatible Design Needed
Deterioration of environmental vacuum may occur due to contamination. Measures needed to protect SMILES operation.
Space Shuttle: Water Dumps
JEM-PM: Cabin Air Vents
Some EMI may deteriorate the data quality of SMILES, even if it is too low to damage the instruments.
Most careful measures for EMI are indispensable.
EM-shielding designs are taken.

34. External Contamination around JEM-EF
Toyohashi, Jan. 6-7, 2000
External Contamination around JEM-EF
J Space Shuttle Water Dumps
Space Shuttle dumps fuel-cell water approximately
every three days, with the flow rate of ~64kg/45min.
J JEM Vacuum System Vents
JEM-PM vents cabin air to provide low-pressure environments for internal payloads, and to depressurize the airlock for EVA.
J Internal/External Outgassing
J Natural Environment

35. Major Impacts on SMILES
Toyohashi, Jan. 6-7, 2000
Major Impacts on SMILES
J Thermal Isolation in the Cryostat
Pressure in the cryostat must be kept below ~10-6 Torr for the thermal isolation.
→ A vacuum valve of the cryostat should be closed during high-pressure periods.
J Reflection / Transmission Loss of the Optics
Water stuck on optical surfaces causes reflection / transmission losses (e.g. ice film with a thickness of ~7mm will result in a transmission loss of 1% at 640 GHz).
→ Sticking fraction on the optics should be evaluated.

36. Ventilation from JEM-PM
Toyohashi, Jan. 6-7, 2000
Ventilation from JEM-PM
JEM vent locations and directions (left panel), and pressure distribution around JEM-EF during the JEM6A/6B operation (right), calculated by SED (2000).

37. Water Dump from Shuttle
Toyohashi, Jan. 6-7, 2000
Water Dump from Shuttle
Radial Dispersion
Angular Dispersion
Dispersion of the water flow calculated by Boeing (1998).

38. Shield against ISS Environmental Fields

39. Design Concept Twofold Electromagnetic Shields:
EM-Shield by System Enclosure: Isolation > 20 dB (Target)
EM-Shield by Receiver Cryostat: Isolation > 60 dB (Target)
To Suppress Radiation Leakage:
Complete Gap Sealing for Enclosure Panels
Indium-coated “O-ring” for All Flanges in the Cryostat
“Back-to-back Horn” for Antenna/Receiver Interface
(Cut-off Waveguide against EMI at 27.5 GHz or less)
To Suppress Leakage through Cables:
Use of Shielded Cables
Use of EMI-shielded Connectors
Use of Low Pass Filters
Strict EMI Design in Each Component

40. Electromagnetic Shielding
Toyohashi, Jan. 6-7, 2000
Electromagnetic Shielding