Status of the ACE-FTS Instrument On-board SciSat-1
Copyright 2006 ABB Bomem Inc. All rights reserved. Page 1 ACE-FTS instrument: after 7.5 years on-orbit Henry Buijs ABB Ryan Hughes U. Of Waterloo FTS heritage ABB Bomem formerly Bomem Inc. Balloon borne solar occultation (1975-1980) To elucidate Stratospheric chemistry related to ozone depletion Successful commercialization of very high resolution FTS
DA8 series with 0.0026 cm-1 resolution (1980-2005) Dynamic alignment flat mirror interferometer Used in many labs to contribute to HITRAN data base Successful commercialization of a rugged industrial FTS Copyright 2006 ABB Bomem Inc. Page 2 Technology used for Cris MB100 series 1986-present Wishbone scan arm with cube corner mirrors
No alignment required Technology used for most ABB satellite FTS projects FTS heritage ABB Bomem formerly Bomem Inc. Ground based Hyper-spectral sounder Measures down-welling spectral radiance Permits Temperature and moisture profiling from ground Copyright 2006 ABB Bomem Inc. Page 3 Good vertical resolution in boundary layer Joint development project with U of Wisconsin
Autonomous operating 3rd gen Background Atmospheric Chemistry Experiment (ACE) development started early 1999 (Phase B contract award) under Canadian Space Agencys Space Science program. Mission objectives: better understanding of atmospheric chemistry of ozone The instrument suite includes an FTS, two 128x128 sun imagers and an active sun-tracker Prime contractor is ABB Bomem Inc., with main subcontractors Copyright 2006 ABB Bomem Inc. Page 4 Ball Aerospace and EMS Technologies. Many persons have contributed to the ACE-FTS development, including universities and research labs. The FTS design is based on the classical Michelson interferometer with a double-pass optical layout. It is tilt and shear compensated and requires no active alignment. The ACE-FTS Instrument was launched August 12th, 2003 Main Design and Programmatic Requirements
ACE science objectives require High spectral resolution (0.02 cm-1), High SNR (> 100) Wide spectral coverage (750-4100 cm-1) Copyright 2006 ABB Bomem Inc. Page 5 Combination of these three requirements resulted in a challenging instrument design. Jacquinot merit factor W is >3x107 Highest merit factor ever targeted for a space-borne spectrometer operating in the infrared. Instrument design is also constrained by low mass (40 kg), power (40 W) and volume allocations from the spacecraft bus. Scisat-1 mission is a small satellite mission concept Program required to design and manufacture a low cost, quicklydeveloped instrument while keeping risks as low as possible. Copyright 2006 ABB Bomem Inc. Page 6 Scisat-1 spacecraft ACE-FTS Optical Layout IN T co rn e r-cu b e
m ir r o r ( 1 1 ) B e a m s p lit t e r / c o m p e n s a to r a ss e m b ly (8 ) IN T c o r n e r -c u b e m i rr o r (1 0 ) ( 1 2 ) : R e f le c t iv e c o a t i n g ( 9 ) : B / S c o a ti n g (1 2 ) L a se r M e tro lo g y D e t e c t io n (9 ) E n d m ir r o r (13 ) Output condenser (14) Copyright 2006 ABB Bomem Inc. Page 7
Cooler window (17) Glare stop (16) L ens Dichroic F o ld m ir r o r (1 5 ) 1 .0 2 m im a g e r ( 2 6 ) B e a m s p li t t e r C o m p e n s a to r L a s e r M e t r o l o g y I n s e r t io n 1 .0 2 m D ic h r o i c Lenses f il t e r ( 2 5 ) ( 2 4 ) F o l d m i rr o r (23 ) (2 2 )
Glare stop 0 .5 2 5 m im a g e r (2 8 ) Lens PV MCT Detector (18) I R F i lt e r (7) PV InSb Detector S eco n da y m i r ro r ( 6 ) F ie l d s t o p ( 5 ) 0 .5 2 5 m f il t e r ( 2 7 ) Aperture stop (4)
S u n tr a c k e r m i rr o r ( 1 ) Le nse s (2 0 ) V I S / N I R - Q u a d C e ll D ic h r o ic Q u a d C e ll (21 ) 1 .5 5 m f il t e r ( 1 9 ) P r im a r y m i r ro r ( 3 ) M A ES TR O In te r fa c e ( 2 ) S olar in p u t Copyright 2006 ABB Bomem Inc. Page 8 ACE interferometer
Copyright 2006 ABB Bomem Inc. Page 9 The ACE-FTS Instrument Interferometer-side Input Optics-side ACE-FTS Interferometer Sub-System ACE-FTS still operating on the primary redundancy side at full resolution Metrology laser power shows a decrease of less than 2% observed over 7.5 years Excellent reliability of the ACE-FTS (more than three original mission lifetime requirement) Copyright 2006 ABB Bomem Inc. Page 10
Copyright 2006 ABB Bomem Inc. Page 11 Integration to spacecraft bus Copyright 2006 ABB Bomem Inc. Page 12 SciSat Inside the Pegasus Fairing Copyright 2006 ABB Bomem Inc. Page 13 ACE in orbit Orbit Characteristics Circular orbit Altitude 650 km,
Inclination 74 Selected to provide high latitude occultations Solar occultation mission Copyright 2006 ABB Bomem Inc. Page 14 Orbital period 98 min. Approximately 15 occultations /day (~5400/year) Tangent height Copyright 2006 ABB Bomem Inc. Page 15 Coverage characteristics
Copyright 2006 ABB Bomem Inc. Page 16 Coverage characteristics Spectral analysis method Exo-atmospheric spectra Do not contain any atmospheric features Atmospheric spectra include above + atmospheric absorptions Ratio atmospheric/exo-atmospheric provides precise atmospheric transmission Subtracting transmission loss of higher layers provides transmittance at tangent height only
Optical beam at tangent height is ~ 3 km Copyright 2006 ABB Bomem Inc. Page 17 Provide instrument response to solar spectrum Limits vertical resolving power Scan time is 2 s. Rate of change during scan depends on beta angle Copyright 2006 ABB Bomem Inc. Page 18 Ace spectra NO2 region Many weak lines of NO2
Copyright 2006 ABB Bomem Inc. Page 19 B3M compared with ACE data CFC12 region CFC12 HNO3 Copyright 2006 ABB Bomem Inc. Page 20 B3M compared with ACE HCl region HCl B3M compared with ACE and DA8 ACE B3M Copyright 2006 ABB Bomem Inc. Page 21 DA8
HCl T P O 3 O 2 N2 SF O 6 C S C2 H C2 2 CH H6 3 HC OH O O H2 H
CO H2 O 2 HC N CF CC 4 CO l4 CO F2 C CH l2 3C l l CF HF C CF -11 CF C-1 HC C 2 F -1 HC C-1 1 3 FC 41 - b
HC 1 42 FC b -2 2 HC N2 O NO 2 N N2 O O H 5 HO N O 2 3 Cl NO O 2 N O 2 H2 O CO
2 CH 4 CO Copyright 2006 ABB Bomem Inc. Page 22 height km ACE profiles profile altitude ranges 140 120 100 80 low high 60
40 20 0 Profile performance Very good absolute concentration determination Limited by HITRAN issues Calibration cannot change over time Does not rely on blackbody calibration sources Vertical resolution ~ 3 km
Copyright 2006 ABB Bomem Inc. Page 23 Exo-atmosphere/atmosphere ratio Vertical sampling < 1km Lower limit of profile Limited by cloud Limited by spectral saturation Upper limit of profile Limited by sensitivity
Copyright 2006 ABB Bomem Inc. Page 24 Example result, CO2 study (P.Y. Foucher et al) On-orbit SNR comparison mid-march 2004 (ss3171) and mid-march 2008 (ss24754) SNR increase Copyright 2006 ABB Bomem Inc. Page 25 SNR degradation Source: ACE Science Team (Ryan Hughes, UofWaterloo) Copyright 2006 ABB Bomem Inc. Page 26 Frequency of occultations with ice 2004 to 2007 2004
2005 2006 2007 On-orbit FTS temperature (interferometer beamspliter) 2004-2008 Increase of temperature of ~1deg/year observed Copyright 2006 ABB Bomem Inc. Page 27 S/C anomaly Source: ACE Science Team (Ryan Hughes, UoWaterloo) In date of June 2008, the temperature of the instrument is 25 degrees Celcius in average; there is still room for further temperature increase as the instrument was qualified during TVAC for temperatures from 0 to 40 degrees Celcius.
Data processing Level 2 data Copyright 2006 ABB Bomem Inc. Page 28 Concentration profiles of molecules Official data processing soon in 5th version Version 1.0 Version 2.0 Version 2.1 Version 2.2 Version 3.0 (tentative) H2O, O3, N2O, CO, CH4, NO,
C2H6, N2, ClO H2O, O3, N2O, CO, CH4, NO, NO2, HNO3, HF, HCl, N2O5, ClONO2, CCl2F2, CCl3F, COF2, CHF2Cl, HDO, SF6, OCS, HCN, CF4, CH3Cl, C2H2, C2H6, N2, ClO, as well as isotopologues for some of these molecules H2O, O3, N2O, CO, CH4, NO, NO2, HNO3, HF, HCl, N2O5, ClONO2, CCl2F2, CCl3F, COF2, CHF2Cl, HDO, SF6, OCS, HCN, CF4, CH3Cl, C2H2, C2H6, N2, ClO,HCOOH, CH3OH, CCl4, CFC113, HCFC-142b,
COCl2, COClF, H2CO, HFC134a, as well as isotopologues for some of these molecules Molecules measured for the first time Copyright 2006 ABB Bomem Inc. Page 29 ACE-FTS is the first instrument on-orbit to measure the following molecules: CFC-113 HCFC-142b COClF
PAN (peroxyaceylnitrate) Future trends Improved vertical resolution Image slicing Improved solar tracking Copyright 2006 ABB Bomem Inc. Page 30 Maintain basic throughput With <1 km vertical resolution
Account for distortion due to refraction Cloud discrimination Copyright 2006 ABB Bomem Inc. Page 31 Future trends Future trends Lower cost missions To increase number of sensors Some reduction of spectral resolution Since ACE has shown the detailed spectrum Copyright 2006 ABB Bomem Inc. Page 32
Good retrievals are possible at lower resolution Smaller instrument Faster scanning Higher SNR Include shorter wavelength To avoid saturation of spectra at lowest altitudes Using weaker overtone Near IR bands
2006 2007 Year About 130 publications identified so far (July 2008) More than 104 with review committees 2008 Copyright 2006 ABB Bomem Inc. Page 34 Conclusion ACE-FTS on Scisat-1 has significantly exceeded its 2 years mission 7th anniversary on August 12, 2010
Very good in-flight performances Excellent scientific returns Thanks to all ACE/SciSat-1 team !
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