The Stratospheric Observatory for Infrared Astronomy (SOFIA) R. D. Gehrz Lead, SOFIA Community Task Force Department of Astronomy, University of Minnesota 1 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Outline • SOFIA Heritage and Context • SOFIA Aircraft and Observatory Development Program • SOFIA Performance Specifications • SOFIA Science • SOFIA Schedule • Summary 2 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Acknowledgements • Nans Kunz, NASA Senior Engineer at NASA ARC and Past Chief Engineer of the SOFIA Program at NASA ARC • Eric Becklin, USRA SOFIA Chief Scientist • Tom Roellig, NASA ARC SOFIA Deputy Project Scientist 3 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Infrared Physics IR = 1 µm ≤ λ ≤ 1000 µm (yellow light = 0.5 µm) ⇒ 3K ≤ T ≤ 3000 K 4 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Blackbody Physics and Infrared Astronomy The Planck Function 2πhc2 1 F = λ λ5 ehc / λkt −1 Wien’s Law λmaxT = 2898 µm deg IR = 1 µm ≤ λ ≤ 1000 µm ⇒ 3K ≤ T ≤ 3000 K 5 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Infrared Astronomy and the Chemical Evolution of the Universe 6 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz The History of Infrared Astronomy at Minnesota William Keck Observatory, 1999 Mauna Kea, HI, 2 x 10-m 1993 2002 1967 1996 UM’s O’Brien, Marine On the St. Croix, MN, 0.8-m 1977 GEMINI North (Mauna Kea, HI) 1970 The Wyoming IR and South (Cerro Pachon, Chile) Observatory, Jelm 2 x 8-m Mountain, WY, 2.34-m 2006 2006 SIRTF 1979 2003 UM’s Mt. Lemmon NASA IRTF, Mauna Kea, HI, 3.0-m The LBT, Mt. Graham, AZ, Observatory AZ, 1.5-m 2 x 8.4-m on a 22.8-m single mount 7 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz The Advantages of a 5.5K IR Telescope in Space • 100% Transmission • One-Million Fold Decrease in Sky Brightness • A One Thousand Fold Increase in Sensitivity 8 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz The History of Flying Infrared Observatories 1999 2002 1967 1967 1974 1977 2009 NASA Lear Jet NASA Kuiper Airborne NASA/DLR Stratospheric Observatory Science Observatory Observatory (KAO) for Infrared Astronomy (SOFIA) objectives 2006 2006 1983 1995 2003 NASA Infrared Astronomical ESA Infrared Space NASA Spitzer Space Telescope Satellite (IRAS) Observatory (ISO) 9 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz SOFIA and its Companions in Space HERSCHEL 2009 2003 SOFIA JWST 2009 2013 10 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz SOFIA Mission Overview, Aircraft Modification, and Status October 29, 2008 AAS/DPS Meeting, Cornell University, Ithaca, NY, July 19, 2008 11 11 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz SOFIA Overview • 2.5 m telescope in a modified Boeing 747SP aircraft – Imaging and spectroscopy from 0.3 µm to 1.6 mm – Emphasizes the obscured IR (30-300 µm) • Service Ceiling – 39,000 to 45,000 feet (12 to 14 km) – Above > 99.8% of obscuring water vapor • Joint Program between the US (80%) and Germany (20%) – First Light Science in 2009 – 20 year design lifetime –can respond to changing technology – Ops: Science at NASA-Ames; Flight at Dryden FRC (Palmdale- Site 9) – Deployments to the Southern Hemisphere and elsewhere – >120 8-10 hour flights per year 12 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz The Advantages of SOFIA • Above 99.8% of the water vapor • Transmission at 14 km >80% from 1 to 800 µm; emphasis on the obscured IR regions from 30 to 300 µm • Instrumentation: wide variety, rapidly interchangeable, state- of-the art –SOFIA is a new observatory every few years! • Mobility: anywhere, anytime • Twenty year design lifetime • A near-space observatory that comes home after every flight 13 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz SOFIA: Selecting the Aircraft • Fuselage diameter (length not an issue) • Payload and loiter time at FL >410 • Cost ($13M in 1995 dollars) Candidate Aircraft Performance 12 10 C141 8 C5A L1011 6 DC10 A310 The winner: 767 4 747 2 - Estimates for Boeing 747-SP incremental drag is included - fuel reserve 0 = 5% of total + Retrofitted with P&W JT9D-7J 40000 60000 80000 100000 120000 30 minutes Payload + Modification Weight engines to provide operational margin 14 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Location of future cavity opening 15 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz New pressure bulkhead Pressurized Cabin- containing Open Port cavity- mission equipment, the science containing telescope instrument, the flight crew, the observatory crew, and the scientists R. D. Gehrz on, WA, February 13, 2009 The Boeing Company, Rent 16 The SOFIA Observatory open cavity Educators work station (door not shown) pressure bulkhead Door.mpg scientist stations, telescope and TELESCOPE instrument control, etc. scientific instrument (1 of 9) 17 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Nasmyth: Optical Layout Observers in pressurized cabin have ready access to the focal plane M2 Pressure bulkhead Spherical Hydraulic Bearing Nasmyth tube f/19.6 Focal Plane M3-1 M3-2 Primary Mirror M1 Focal Plane 18 Imager The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Telescope Size is Maximum that can fit Available Volume 19 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz MajorMajor TelescopeTelescope ComponentsComponents M2 Cameras Forward Bulkhead Science Counter Hydraulic System Instrument Weight Motors Brakes Bearing Sphere M3-1 Focal Plane M3-2 FocalFocal Plane Plane Vibration ImagerImager Isolation Primary Mirror M1 20 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz First Light August 2004 21 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Installing the bearing sphere 22 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Incremental Critical Design Review = ICDR Frame Modifications and Sill Beams FS 1480 Upper Main Sill ICDR #1 Forward Bulkhead Main Frames ICDR #1 Upper Auxiliary Sill ICDR # 1 Lower Main Sill ICDR #1 Fwd Auxiliary Frame Up ICDR #4 Fwd Aft Auxiliary Frame ICDR #4 FS 2000 Lower Auxiliary Sill ICDR#1 23 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz 24 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz FEM Predictions for Unmodified Aircraft 25 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz FEM Validation: Pre-Modification Flight Test Data Sample Longitudinal Strain - Positive Vertical Acceleration FEM Predicted Longitudinal Strain and Flight Test Calibrated Strain vs. Water Line FEM Station 1990 (LHS) 400 350 300 250 200 FEM Water Line, in. 150 Flight Test Stringers Flight Test Skins 100 -2500 -2000 -1500 -1000 -500 0 500 1000 1500 2000 2500 Microstrain, uin/in 26 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Modified Baseline Finite Element Model 27 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz New 21.3 foot diameter Pressure Bulkhead Bulkhead simulator used in Germany for Telescope Assembly buildup FEM Bulkhead on Delivery 28 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz FEM Predictions for Modified Aircraft 29 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Upper Rigid Door Drive Upper Rigid Door (URD) Aperture Inflatable Seal Aircraft Lower Flexible Door (LFD) Forward Direction 30 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Door System Fairings Aft Fairing Forward Fairing Fiberglass Fiberglass Close-out Close-out Lower Fairing 31 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz SOFIA Door System 32 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Control Cables - SOFIA Routing Pitot Lines 96128400 Flight Control Cables 96128500 Hydraulic Lines (left side) 96128300 FWD APU Fuel Line 96128210 33 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Control Cables STA 1264 STA 1350 BP#1 BP#2 Forward BP#3 STA 1940 BP#4 View Looking Down/Fwd STA 2078 34 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Control Cable Re-routing Details BP#1 BP#2 Forward Bulkhead Plate STA1394 35 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz SOFIA Wind Tunnel Testing and CFD Modeling • Wind tunnel testing was begun in 1990 • Five wind tunnel tests on a 7% model to investigate cavity acoustics during 1990 - 1997 • Wind tunnel tests on a 3% model to investigate the impacts of the SOFIA modification on aircraft handling characteristics • Multiple Computational Fluid Dynamics (CFD) analyses • Full scale flight tests will be conducted during summer 2009 to validate the wind tunnel test and CFD results. 36 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Studies of Cavity Acoustics: SOFIA 7% model in Ames 14 foot Transonic Wind Tunnel 37 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz 7% Wind Tunnel Tests Test Description/Conditions • Boeing 747-SP 7% Model • NASA ARC 14-Foot Tunnel • Mach: 0.3<M<0.92 • Yaw: -4.5<b<4.5o • Angle of attack: 2o<a<5o • TA Elevation: 25o <g< 60o Data Acquired /Design validation • Aero-acoustics • Telescope torque Partial External Door • Pressure loads • Boundary layer characterization 38 The Boeing Company, Renton, WA, February 13, 2009 R. D. Gehrz Dynamic Environment in the Cavity Cabin Shear Layer at Cavity Opening Standing Waves Excited by the Shear Layer Science Instrument Wind in Cavity Induced by the Shear Layer Aircraft Vibrations 39 The Boeing Company, Renton, WA, February 13, 2009 R.