Instrument Incubator Programs @ Langley Calibration Needs and CLARREO

1. Z2 F- F+ F- Z1 F+ Instrument Incubator Programs @ LangleyCalibration Needs and CLARREO Marty Mlynczak & Dave Johnson Deron Scott, Harri Latvakoski, & Gail Bingham June 12 2008 CLARREO Meeting @ NIST INFLAME CORSAIR FIRST

2. Overarching Objectives • To improve understanding Earth’s climate and climate change through a combination of new observations and innovative data analysis • Work focuses on: • “Far-Infrared” part of the spectrum 15 - 100 m • FIRST; INFLAME; CORSAIR; FIDTAP • Solar spectrum via measurement of atmospheric heating rates • INFLAME • Approach: • Develop new technology where needed (IIP, ATI, ACT) • Exploit existing data sets as applicable (EOS, IIP) • Generate new data sets to fill voids in knowledge (CLARREO) Demonstrate accurate, stable instruments & related technology for space based on well-defined science measurement objectives

3. Overview Since 2001 Langley has had 3 “Instrument Incubator Projects” (IIP) funded by NASA • FIRST (IIP 2001) • INFLAME (IIP 2004) • CORSAIR (IIP 2007) All are “CLARREO Relevant” New IIP (CORSAIR) focuses on key technologies to achieve SI-Traceable far-IR radiances from space Will review the CORSAIR elements related to calibration and far-IR radiance standards today

4. Instrument Incubator Program - IIP Far-Infrared Spectroscopy of the Tropsophere - FIRST PI: Dr. Marty Mlynczak/LaRC Description and Objectives Measure the Far-Infrared spectrum of the Atmosphere and Earth (10 to 100 mm) Far-IR observations are the key to understanding the greenhouse effect and the radiative feedbacks associated with increased anthropogenic forcings Far-IR key to understanding cirrus effects, etc. Approach FIRST spectrum from flight demo 7 June 2005 Complete infrared spectrum observed • Simulate space environ. • Develop • - High-throughput Michelson FTS • - Broad-bandpass beamsplitter • - Advanced detector system Status 6/2005 – Successful flight demo/balloon flight 9/2006 – Second flight for CALIPSO validation 3/2007 – Ground calibration vs. AERI at UW 4/-10/2009 - RHUBC/FORGE campaign Chile 10/2010 - CORSAIR detector evaluation @ LaRC Journal articles forthcoming Partners Utah State Univ. – Interferometer Harvard SAO – Beamsplitters 19-member science advisory team

5. FIRST Radiances June 2005 and September 2006 June 7 2005 14:25 LT September 18 2006 14:03 LT

6. Instrument Incubator Program - IIPIn-Situ Net Flux within the Atmosphere of the Earth - INFLAMEPI: Dr. Marty Mlynczak/LaRC Project Objectives • Develop and demonstrate an instrument that directly measures the net radiative flux within the Earth’s troposphere and lower stratosphere with stability sufficient to derive atmospheric heating rates with an accuracy of 10% in a 1 km thick layer of the troposphere. • Collect flight atmospheric data to determine the radiant flux, net flux, and net flux divergence throughout the free troposphere and lowermost stratosphere. INFLAME payload on LearJet wing tip pods Approach Key Milestones • Develop two separate Fourier Transform Spectrometers, one for infrared radiation, one for visible radiation • Mount on wing tip pods of an aircraft • Cycle up and down in altitude recording vertical profile of net flux • Derivative of net flux w/r/t altitude is the atmospheric heating rate due to radiation • Small enough, and low cost, to enable several to be deployed at once to address issues of cloud noise, inhomogeneous nature of aerosol layers, etc. • PDR/1rst Annual Review Nov/06 • Flight Vehicle selected Mar/07 • Optics Designs completed Sep/07 • CDR Oct/07 • Mechanical Fabrication completed Mar/08 • Instrument assembly completed Jul/08 • System test & integration completed Sep/08 • FRR / Flight Test Jan/09 TRLin = 4

7. Detector Blackbody Beamsplitter Instrument Incubator Program - IIP- CORSAIRCalibrated Observations of Radiance Spectra from the Atmosphere in the far-IRPI: Dr. Marty Mlynczak/LaRC Objective Advance to TRL 6 remaining technologies central to CLARREO • Infrared detector elements sensitive from 15 to 50 cm-1 that do not require cryogenic cooling with D* > 1e+10 - Raytheon Vision Systems • SI traceable blackbodies and radiance standards for wavelengths beyond 15 µm - SDL, NIST • Robust optical beamsplitters with continuous high efficiency over the full 200 to 2000 cm-1 spectral range - ITT System diagram highlighting technologies addressed by CORSAIR Approach: • Develop antenna-coupled Thz detectors and demonstrate performance @ LaRC in FIRST • Develop and test far-IR blackbodies and SI-traceable standards; Use infrared facilities at SDL and validate through NIST • Develop multilayer coatings for broadband beamsplitter and demonstrate performance Key Milestones Year 1: • Blackbody (BB) characterized at NIST Q3 • Detector lot 1 characterization complete Q4 • Beamsplitter design complete Q3 Year 2: • Flight BB prototype fabrication complete Q3 • Detector lot 2 characterization complete Q4 • Beamsplitter R and T measurements complete Q4 Year 3: • Prototype BB testing complete Q3 • Detector lot 2 testing at LaRC complete Q4 • Beamsplitter performance testing complete Q2 CoIs: David Johnson, Nurul Abedin, Xu Liu, LaRC; David Jordan, ITT; Jinxue Wang, Raytheon VS; Gail Bingham, Harri Latvakoski, USU SDL; Kevin Bowman, JPL; Simon Kaplan, NIST. TRLin = 3 (detectors)

8. Calibrated Observations of Radiance Spectra from the Atmosphere in the far-InfraRed - CORSAIR Major Technology Elements • Passively Cooled Detectors (Raytheon Vision Systems) • Antenna Coupled Terahertz Devices • Potential for 100 to 1000 times more sensitive (D*) than pyroelectric • Substantial prior DARPA and Homeland Security investment • SI Traceable Blackbodies in Far-IR (SDL; NIST) • Flight prototype blackbody w/ well-characterized emissivity • Phase change cells incorporated for accurate temperature determination • On-orbit emissivity monitor in far-IR • Broad Bandpass Beamsplitters (ITT) • Cover 5 to 50 m region in 1 beamsplitter • Potentially enables 1 instrument to cover CLARREO range • Detector evaluation to take place in FIRST @ Langley in Year 3 • LaRC; JPL; Raytheon

9. CORSAIR - Far-IR Calibration • Far IR Calibration Background • FIRST’s 2-port calibration system contained a blackbody operating at ambient temperatures and an open port used to observe cold space. • Cost limitations limited exposure of the FIRST blackbodies to SI standards as required for the CLARREO mission. • Techniques to test and monitor the emissivity must also be demonstrated. • SDL will continue to develop its source evaluation capabilities – including NIST traceability • NIST certification of the FIRST calibration source • Phase change materials for long term flight monitoring • Far IR flight emissivity monitoring • Demonstration Flight BB

10. SDL’s SI-Traceable Source Evaluation

11. NIST Traceable Radiance and Emissive Standards • SDL’s Thor Chamber can host the TXR for MW/LW IR • Description of SDL equipment • SDL has a large LN2 cooled thermal vacuum chamber that is already operational that is used to perform spectral radiance transfers to be made to large vacuum blackbodies. • SDL is developing a transfer radiometer/spectrometer (SDL-XR) • The SDL-XR will be operational and tested in the summer or fall of 2008. • SDL-XR provides spectral radiance testing capability • Source-based radiance scale (LWIRCS) that will be calibrated by NIST at the LBIR chamber. • This capability is being developed to allow the spectral radiance scale to be transferred to working blackbodies.

12. Long Wavelength IR Cavity Source (LWIRCS) • This is the upgraded FIRST Calibration Source being readied for calibration at NIST’s LBIR. • LWIRCS has 5 PRT temperature sensors to measure the temperature of the cavity. • The PRT sensors are mounted in a way that allows them to be removed, re-calibrated, and re-installed while maintaining the mounting stresses and heat sinking of the electrical leads.

13. SDL-XR transfer radiometer • The SDL transfer radiometer includes a Michelson interferometer that will operate at < 50K. • The SDL-XR has a 70 mm entrance aperture and a 1 mrad field of view. • The interferometer spectral range from 2 to 28 microns, with up to 1 wavenumber spectral resolution. • The SDL-XR can also operate in radiometer mode with ~12 spectral bands. • Picture shows the SDL-XR during the initial cold test in October 2007. • Operational with initial testing completed in the summer to fall of 2008.

14. CORSAIR Calibration Tasks • Achieve SI traceable calibration of blackbodies beyond 15 μm, calibrated to better than 0.1K (3σ), with the calibration capable of being maintained on orbit. • Establish absolute temperature calibration transfer to orbit by adding phase transition cells to the blackbodies. • These phase transition cells will allow absolute calibration of the blackbody temperature sensors to the 10 mK level or better. • Phase transition cells will be added to LWIRCS and an additional blackbody to be developed at SDL. • Improve our knowledge of the emissivity of the Far IR blackbodies to determine if the design meets CLARREO requirements. • Includes extending our capability to measure spectral emissivity to 100 μm. • Develop on orbit emissivity monitoring for CLARREO Far-IR sources. • Develop a flight prototype BB for the Far-IR. • Key is to achieve efficient coordination with NIST in all of the above!

15. Where we will be upon completion of CORSAIR • Three FTS instruments well characterized across spectrum • Entire IR (FIRST; INFLAME) • Visible (INFLAME) • Absolute calibration and stability evaluated and documented • New detector technologies developed and demonstrated for far-IR • Uncooled antenna-coupled detectors (CORSAIR) • Cooled BIB detectors (FIDTAP; ACT) • Evaluated against COTS pyroelectrics in FIRST • Offers evaluation and range of technologies for CLARREO • Beamsplitters (FIRST; CORSAIR) • Far-IR specific and Broadband 5-50 m • SI-traceable blackbodies in far-IR (CORSAIR) • Flight far-IR propotype NIST certified • With on-orbit far-IR emissivity monitoring & phase change cells • Detailed evaluation of far-IR properties of middle troposphere and cirrus optical properties (FORGE/RHUBC) • Extensive experience in all aspects of FTS design, calibration, flight, and data reduction