Universities Space Research Association NASAs Stratospheric Observatory for
Universities Space Research Association NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) Gordon J. Stacey, Cornell University (many slides borrowed from Robert Gehrz, U. Minnesota) Communications Integrated Systems
Universities Space Research Association The SOFIA Observatory q 2. 5 m telescope in a modified Boeing 747 SP aircraft Ø Optical to millimeter-wavelengths Ø Emphasis on the obscured IR (30 -300 m) q Joint Program between the US (80%) and Germany (20%) q First Light Will Occur in 2009 Ø Built on NASA’ Airborne Astronomy Heritage Communications Integrated Systems 2
Universities Space Research Association SOFIA Forte: the Far -Infrared q SOFIA is unique in the far-IR wavelength bands: 30 to 300 m – a region of the electromagnetic spectrum that is totally obscured by telluric water vapor for ground based observatories. q Flying at > 39, 000 feet gets you above 99% of the obscuring water vapor. q Why do we do it? Communications Integrated Systems 3
Universities Space Research Association Why Study the Far -Infrared? Extinction and Energetics… Extinction The energy for most of the radiant light in a galaxy originates in the photospheres of stars visible light. Ø However, stars form in dusty molecular clouds. This dust is small r ~ 0. 1 m ~ wavelength of visible light scattered and absorbed (extinction) Ø Can’t see star formation regions in the visible must go to longer wavelengths Effect is huge! Only one visible photon in 10 billion from the Galactic Center reaches us, but > 90% at > 40 m reaches us! Communications Integrated Systems 4
Extinction Far-IR (IRAS) Image: Warm 2 m (2 MASS) Image: Galactic dust Optical Image: Nearby stars Center Cluster 5
Universities Space Research Association Energetics: What glows in the far. IR? The Planck Function Wien’s Law Far-IR = 30 µm ≤ ≤ 300 µm 10 K ≤ T ≤ 100 K • Robert Gehrz, U. Minnesota Communications Integrated Systems
Universities Space Research Association Things Look Different at Different Wavelengths! Warm eyes & ears Cool nose Cool fur Communications Integrated Systems 10 m image of a cat 7
Universities Space Research Association Energetics The same is true for stars Much of the light energy in the local Universe arrives in the far-IR bands as thermal radiation from warm dust q Example 1 – Dust: Protostars glow in the submillimeter band Ø Stars form in the dust cores of giant molecular clouds Ø As the core collapses to form a protostar, its gravitational energy is converted into kinetic energy (heat) – the core heats up. Ø The first glow of a protostar is in the far-IR band Communications Integrated Systems 8
Orion Nebula: Visible and Far -IR Universities Space Research Association Communications Integrated Systems 38 m Image: KWIC-Kuiper Airborne Observatory Harry Latvakoski, Cornell Ph. D 9
Universities Space Research Association Energetics: Gas Cooling q Example 2 – Spectral Lines -- Dominate the cooling and trace physical conditions of the gas Ø To form a star, gas clouds must collapse Ø As a cloud collapses under gravity, it heats up – this would stop collapse unless it can cool effectively Ø The spectral lines in the far-IR and submillimeter bands are the primary coolants for the neutral gas that forms stars q Most important cooling lines include H 2 O, SO 2, H 2 and CO rotational lines, [CI] [CII], [OI], and [NII] fine structure lines – all of which lie in the far-IR band Communications Integrated Systems 10
Universities Space Research Association The Far -Infrared Regime is Exciting – So Why Isn’t Everyone Doing it? 14, 000 feet 41, 000 feet Communications Integrated Systems 11
Universities Space Research Association The History of Airborne Astronomy NASA Lear Jet Observatory 1967 – 1983+ 1999 2002 q “Pioneering” Airborne Astronomical Telescope – 30 cm aperture q 2 hr 10 m Flights – zip up to 45, 000 feet q First observations ever of many of the most important cooling lines – hadn’t even been seen in the lab! q Produced many (~20) Ph. Ds – you are looking at the last one… Communications Integrated Systems
Universities Space Research Association Kuiper Airborne Observatory (KAO) q Natural Follow-on to the Lear Jet q Modified C 141 Starlifter q Pressurized cabin – “shirt sleeve” environment q Telescope balanced and floated on an “air-bearing” q Gyro stabilized to within < 5” q 91. 4 cm (36”) telescope q 7. 5 hr flights, 6. 5 of which above 39, 000 feet q Produced > 60 Ph. Ds Communications Integrated Systems q Guiding done with focal plane camera and computerized feedback to torque motors on the telescope 13
Universities Space Research Association KAO Discoveries q 1977 – Five thin rings of Uranus discovered – flight from Perth, Australia over the Indian Ocean – mobility of telescope enables stellar occultation viewing q Unexpectedly large far-infrared luminosities of galaxies q Self luminosities of Jupiter, and Saturn q Discoveries of young stars being formed q First strong evidence for a massive (few million) solar mass black hole in the center of the Galaxy q Water discovered in the atmosphere of Jupiter via impacts of Comet Shoemaker-Levi (1994) q 1985 – First detection of a natural interstellar infrared laser Many of Today’s Leaders in Infrared and Submillimeter Astronomy – Particularly in Instrumentation – Cut Their Teeth on Airborne Astronomy: Communications Integrated Systems 14
Universities Space Research Association SOFIA: The Stratospheric Observatory for 1999 Infrared Astronomy 2009 – 2029… 2002 2006 Communications Integrated Systems 2006
Universities Space Research Association The SOFIA Observatory q 2. 5 m telescope in a modified Boeing 747 SP aircraft q Operating altitude Ø 39, 000 to 45, 000 feet (12 to 14 km) Ø Above > 99% of obscuring water vapor q Joint Program between the US (80%) and Germany (20%) q First Light Science 2009 Ø Ø Ø 20 year design lifetime Based at NASA Dryden Research Center Science Operations at NASA-Ames ~ 80 -people, 20% German Deployments to the Southern Hemisphere and elsewhere >120 8 -10 hour flights per year Built on NASA’ Airborne Astronomy Heritage Communications Integrated Systems 16
Universities Space Research Association Communications Integrated Systems 17
Universities Space Research Association Nasmyth: Optical Layout Pressure bulkhead M 2 Spherical Hydraulic Bearing Nasmyth tube Focal Plane M 3 -1 M 3 -2 Focal Plane Communications Integrated Systems Imager Primary Mirror M 1 18
Universities Space Research Association Telescope and aperture assembly Communications Integrated Systems 19
Universities Space Research Association 2. 7 -meter (106 inch) f/1. 28 Primary Mirror after final polishing Communications Integrated Systems 20
Universities Space Research Association Installing the bearing sphere Communications Integrated Systems 21
Universities Space Research Association Installation of the Secondary Mirror Communications Integrated Systems 22
Universities Space Research Association Installation of the Tertiary Mirror Communications Integrated Systems 23
Universities Space Research Association The Un-Aluminized Primary Mirror Installed Communications Integrated Systems 24
Universities Space Research Association Science Capabilities q 8 arcmin diameter field of view allows use of very large detector arrays – first light cameras will have 10 times the number of pixels as those on KAO q Image size is diffraction limited beyond 15 µm, making images 3 times sharper than the best previous facilities including KAO and the Spitzer Space Telescope q Because of large aperture and better detectors, sensitivity for imaging and spectroscopy will be similar to the space observatory ISO • Robert Gehrz, U. Minnesota Communications Integrated Systems 25
Universities Space Research Association SOFIA Airborne! 26 April 2007, L-3 Communications, Waco Texas: SOFIA takes to the air for its first test flight after completion of modifications • Robert Gehrz, U. Minnesota Communications Integrated Systems 26
Universities Space Research Association The First Test Flight of SOFIA April 26, 2007 at WACO, Texas • Robert Gehrz, U. Minnesota Communications Integrated Systems
Universities Space Research Association SOFIA’s Instrument Complement q SOFIA is an airborne mission, with a long life-time. Therefore, unlike space missions, it supports a unique, expandable instrument suite q SOFIA covers the full IR range with imagers and low, moderate, and high resolution spectrographs q Nine instruments are under development now. Four will be available at first light in 2009 q SOFIA can take fully advantage of improvements in instrument technology so that the instruments will always be state-of-the-art. q SOFIA will continue the airborne astronomy tradition of providing a platform where the next generation instrumentation scientists can be trained. Communications Integrated Systems 28
Universities Space Research Association Spectral resolution SOFIA Performance: Spectral Resolution of the First Generation Science Instruments 10 8 10 7 10 6 10 5 10 4 10 3 GREAT CASIMIR EXES FLITECAM FORCAST 10 2 10 1 10 0 HIPO FORCAST 1 Communications Integrated Systems 10 Wavelength [µm] FIFI LS SAFIRE HAWC 1000 29
Universities Space Research Association SOFIA’s 9 First Generation Instruments 4. 5 -28. 3 * Listed in approximate order of expected in-flight commissioning % Operational (August 2004) § Uses non-commercial detector/receiver technology Science Communications Integrated Systems 30
Universities Space Research Association Early Science Instruments and Observations Working FORCAST (Cornell) instrument at Palomar in 2005 Successful lab demonstration of GREAT in July 2005 Map the Orion Nebula at 38 µm with High J CO and HCN observations unprecedented angular resolution and of Orion protostars to quantify gas sensitivity to investigating protostars cooling and density • Robert Gehrz, U. Minnesota Communications Integrated Systems 31
Universities Space Research Association Four First Light Instruments Working/complete HIPO instrument in Waco on SOFIA during Aug 2004 Working/comple te FLITECAM instrument at Lick in 2004/5 Working FORCAST instrument at Palomar in 2005 Successful lab demonstration of GREAT in July 2005 • Robert Gehrz, U. Minnesota Communications Integrated Systems 32
Universities Space Research Association Flight Profile 1 Performance with P&W JT 9 D-7 J Engines: Observations - start FL 410, duration 7. 1 Hr ASSUMPTIONS ZFW 381, 000 LBS. ENGINES OPERATE AT 95% MAX CONT THRUST AT CRUISE 25, 000 LBS. FUEL TO FIRST LEVEL OFF CLIMB TO FIRST LEVEL-OFF AT MAX CRUISE WT LANDING WITH 20, 000 LBS. FUEL BASED ON NASA AMI REPORT: AMI 0423 IR BASED ON 747 SP FLIGHT MANUAL TABULATED DATA STANDARD DAY PLUS 10 DEGREES C FL 410, 4. 2 CRUISE SPEED-MACH. 84 GW 542. 0 FL 430, 2. 9 Hr GW 458. 0 Hr CRUISE 52, 000 LBS. FUEL F. F. 17, 920 LBS/HR. CRUISE 84, 000 LBS. FUEL F. F. 20, 200 LBS/HR. CLIMB 25, 000 LBS. FUEL. 5 HRS. START, TAXI, TAKEOFF GW 570. 0 3000 LBS TAXI FUEL TOTAL FUEL USED = 169, 000 LBS. (24, 708 Gallons) TOTAL CRUISE TIME = 7. 05 HRS. TOTAL FLIGHT TIME = 8. 05 HRS • Robert Gehrz, U. Minnesota Communications Integrated Systems DESCENT GW 406. 0 5, 000 LBS. FUEL. 5 HRS. LANDING GW 401. 0 20, 000 LBS FUEL 33
Universities Space Research Association Flight Profile 2 Performance with P&W JT 9 D-7 J Engines: Observations - start FL 390, duration 10. 2 Hr ASSUMPTIONS ZFW 381, 000 LBS. ENGINES OPERATE AT 95% MAX CONT THRUST AT CRUISE 25, 000 LBS. FUEL TO FIRST LEVEL OFF CLIMB TO FIRST LEVEL-OFF AT MAX CRUISE WT LANDING WITH 20, 000 LBS. FUEL BASED ON NASA AMI REPORT: AMI 0423 IR BASED ON 747 SP FLIGHT MANUAL TABULATED DATA STANDARD DAY PLUS 10 DEGREES C FL 410, 4. 2 CRUISE SPEED-MACH. 84 GW 542. 0 GW 610. 0 START, TAXI, TAKEOFF GW 638. 0 3000 LBS TAXI FUEL GW 458. 0 Hr CRUISE 52, 000 LBS. FUEL F. F. 17, 920 LBS/HR. CRUISE 84, 000 LBS. FUEL F. F. 20, 200 LBS/HR. FL 390, 3. 1 Hr CLIMB 25, 000 LBS. FUEL. 5 HRS. FL 430, 2. 9 Hr DESCENT GW 406. 0 5, 000 LBS. FUEL. 5 HRS. CRUISE 68, 000 LBS. FUEL F. F. 21, 930 LBS/HR. TOTAL FUEL USED = 237, 000 LBS. (34, 650 Gallons) TOTAL CRUISE TIME = 10. 15 HRS. TOTAL FLIGHT TIME = 11. 15 HRS. • Robert Gehrz, U. Minnesota Communications Integrated Systems LANDING GW 401. 0 20, 000 LBS FUEL 34
Universities Space Research Association Example: 12. 3 h flight, 7 h on Sgr A* Communications Integrated Systems 35
Universities Space Research Association Debris Disks is? ) dusty disks are common around young main sequence stars by mass) of the interstellar medium er gas disk around these stars? The high resolution spectrograph EXES on SOFIA is uniquely sensitive for probing the abundance, kinematics, and evolution of the most abundant molecule, molecular hydrogen: q. Is there only dust or also a much greater gas reservoir? q. What are the dynamics of these disks – dynamics reveal gas gaps created by Jupiter mass planets. Do we • Robert Gehrz, U. Minnesota (indirectly) detect any? Communications Integrated Systems 36
Universities Space Research Association The Debris Disk of Fomalhaut FORCAST will provide the highest spatial resolution measurements to date. 450 m 850 m 20 0 -20 FORCAST beam at 38 m q Fomalhaut at 70, 160 (Spitzer), 450, and 850 m (SCUBA) (Images are on the same scale with north up and east on the left) q FORCAST beam size is shown in red • Robert Gehrz, U. Minnesota Communications Integrated Systems 37
Universities Space Research Association SOFIA Will Make Unique Contributions to Comet Science q Comets are the Rosetta Stone of the Solar System containing primordial material dating from the epoch of planet building. q Water is the driving force in comets; water in comets was first discovered with the KAO q Organic materials are also observable with SOFIA enables: q Access to water vapor and CO 2 spectral features inaccessible from the ground q Observations of comet apparitions from both hemispheres • Robert Gehrz, U. Minnesota Communications Integrated Systems 38
Universities Space Research Association Extra-solar Planet Transits Artist’s concept of planetary transit and the lightcurve of HD 209458 b measured by HST revealing the transit signature SOFIA flies in exceptionally stable atmosphere so that it is an excellent platform for observing extrasolar planetary transits SOFIA’s HIPO and FLITECAM instruments, which can be mounted simultaneously, will enable observations of the small variations in stellar flux due to a planet transit to: q Provide good estimates for the mass, size and density of the planet q Reveal the presence of star spots, satellites, and/or planetary rings • Robert Gehrz, U. Minnesota Communications Integrated Systems 39
Universities Space Research Association Occultation astronomy with SOFIA Pluto occultation light-curve observed on the KAO (1989) probes the atmosphere q. SOFIA can fly anywhere on the Earth, allowing it to position itself under the shadow of an occulting object q. Occultations yield sizes, atmospheres, and possible satellites of Kuiper belt objects and newly discovered planet-like objects in the outer Solar system. q. The unique mobility of SOFIA opens up some hundred events per year for study compared to a handful for a fixed observatory, and enables study of comets, supernovae and • Robert Gehrz, U. Minnesota other serendipitous objects Communications Integrated Systems 40
Feeding the Black Hole in the Center of the Galaxy One of the major discoveries of the KAO was a ring of dust and gas orbiting the very center of the Galaxy Astronomers at ESO and Keck detected fast moving stars revealing a 4 x 106 solar mass black hole at the Galactic Center KWIC-KAO: Latvakoski et al. 1999 (Cornell Ph. D) q The ring of dust and gas will fall into the black hole q SOFIA’s angular resolution and spectrometers will tell us: Ø How much matter gets fed into the black hole? Ø How much energy is released? – Will we have an outburst? Ø What is the relationship to high energy active galactic nuclei? 41 • Robert Gehrz, U. Minnesota
Universities Space Research Association Summary q SOFIA is the next generation airborne observatory q SOFIA promises lots of very exciting science from the first light instruments q SOFIA’s long lifetime ensures a continuing platform for creation of state of the art instrumentation from the latest technologies – devices can be proven before being subjected to the unforgiving environment of space q Airborne astronomy is a proven path for educating the next generation of instrumentation scientists – SOFIA promises to continue this vital tradition Communications Integrated Systems 42
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