SPITZER SPACE TELESCOPESPITZER SPACE TELESCOPE

The Rationale for Infrared The Rationale for Infrared AstronomyAstronomy

reveal reveal coolcool states of matter states of matter

explore the explore the hiddenhidden Universe Universe

provide access to many provide access to many spectral featuresspectral features

probe the probe the early lifeearly life of the cosmos of the cosmos

WANT TO SEE...WANT TO SEE... Formation of Formation of Planets and StarsPlanets and Stars

Comets, Primordial Solar SystemComets, Primordial Solar System Planetary Debris DisksPlanetary Debris Disks Protostellar WindsProtostellar Winds Brown Dwarf SurveyBrown Dwarf Surveyss

Origin of Origin of Energetic Galaxies and QuasarsEnergetic Galaxies and Quasars Spectra of Luminous Galaxies Spectra of Luminous Galaxies

Distribution of Distribution of Matter and GalaxiesMatter and Galaxies Deep 10 to 100 Micron SurveysDeep 10 to 100 Micron Surveys Galactic Halos and Missing Mass Galactic Halos and Missing Mass

Formation and EvolutionFormation and Evolution of Galaxies of Galaxies ProtogalaxiesProtogalaxies

OVERVIEWOVERVIEW Recent HistoryRecent History InnovationsInnovations

Clever Choice of OrbitClever Choice of OrbitCryogenic ArchitectureCryogenic Architecture

TechnologyTechnologyTelescopeTelescopeMultiple Instrument ChamberMultiple Instrument ChamberInfraRed Array CameraInfraRed Array CameraInfraRed SpectrographInfraRed SpectrographMultiband Imaging PhotometerMultiband Imaging PhotometerOuter ShellOuter Shell

Final NotesFinal Notes

DE-EVOLUTION OF SPITZER

Innovations: Clever Choice of Orbit Innovations: Clever Choice of Orbit

An important breakthrough in the redesign of An important breakthrough in the redesign of Spitzer was to Spitzer was to abandonabandon the idea of placing the idea of placing the observatory into the observatory into Earth orbitEarth orbit and instead and instead to insert it into an to insert it into an Earth-trailing Earth-trailing heliocentric orbit. heliocentric orbit.

Innovations: Clever Choice of OrbitInnovations: Clever Choice of Orbit

A consequential benefit of the solar orbit is that Spitzer A consequential benefit of the solar orbit is that Spitzer will have a will have a large instantaneous viewlarge instantaneous view of the celestial sky. of the celestial sky.

......the Observatory cannot point closer than 80 degrees the Observatory cannot point closer than 80 degrees in the direction of the Sun, in order to minimize the in the direction of the Sun, in order to minimize the thermal heating of the telescope by solar radiation. thermal heating of the telescope by solar radiation.

… …it cannot point more than 120 degrees away from the it cannot point more than 120 degrees away from the direction of the Sun, because of need to illuminate the direction of the Sun, because of need to illuminate the solar panels and produce electricity to power the solar panels and produce electricity to power the Observatory. Observatory.

Spitzer Sky Visibility in ecliptic (top), equatorial (middle), and Galactic (bottom) celestial coordinates.

About a About a third of the skythird of the sky will be will be instantaneously visible to Spitzer instantaneously visible to Spitzer at any given time. at any given time.

This broad window on the sky will This broad window on the sky will simplify scheduling and simplify scheduling and operations of Spitzer, and will operations of Spitzer, and will allow it to achieve very high allow it to achieve very high

astronomical observingastronomical observing efficiency.efficiency.

Innovations: Cryogenic Innovations: Cryogenic ArchitectureArchitecture

Unlike Unlike IRASIRAS and and ISOISO, Spitzer adopts an , Spitzer adopts an innovative "innovative "warm-launchwarm-launch" cryogenic " cryogenic architecture architecture

This innovative launch architecture, This innovative launch architecture, combined with 360 liters of liquid combined with 360 liters of liquid helium, yields an estimated mission helium, yields an estimated mission lifetime of about lifetime of about 55 years years

IRASIRAS used 520 liters of cryogen during used 520 liters of cryogen during its 10-month mission and its 10-month mission and ISOISO used used 2140 liters for to achieve a mission 2140 liters for to achieve a mission lifetime of nearly 2.5 years lifetime of nearly 2.5 years

Spitzer Technology OverviewSpitzer Technology Overview

The Cryo-Telescope Assembly, shown in The Cryo-Telescope Assembly, shown in blueblue, is , is cooledcooled to within a few to within a few degrees above absolute zero with liquid helium. degrees above absolute zero with liquid helium.

The warmer spacecraft, shown in The warmer spacecraft, shown in redred, is , is uncooleduncooled. .

Spitzer's TelescopeSpitzer's Telescope

a a lightweightlightweight reflector of Ritchey- reflector of Ritchey-Chrétien Chrétien ((less than 50 kg less than 50 kg ))

has an has an 85 cm85 cm diameter aperture diameter aperture

aall of its parts, except for the mirror ll of its parts, except for the mirror supports, are made of light-weight supports, are made of light-weight berylliumberyllium ( (because because of of ititss low heat low heat capacity at very low temperaturescapacity at very low temperatures ) )

attached to the top of the vapor-attached to the top of the vapor-cooled cryostat vacuum shellcooled cryostat vacuum shell

Two views of the assembled telescope(Ball Aerospace)

Spitzer's Multiple Instrument Spitzer's Multiple Instrument ChamberChamber

contains the cold partscontains the cold parts of Spitzer's three science instruments, IRAC, of Spitzer's three science instruments, IRAC, IRS, and MIPS, as well as the pointing calibration reference sensorIRS, and MIPS, as well as the pointing calibration reference sensor

built to be so tightbuilt to be so tight that no light can get through it except that which is that no light can get through it except that which is allowed to be detected directly by the instrumentsallowed to be detected directly by the instruments

Spitzer's Infrared Array CameraSpitzer's Infrared Array Camera

provides imaging capabilities at near- and provides imaging capabilities at near- and mid-infrared wavelengthsmid-infrared wavelengths

a four-channel camera that provides a four-channel camera that provides simultaneous 5.12 x 5.12 arcmin images simultaneous 5.12 x 5.12 arcmin images at 3.6, 4.5, 5.8, and 8 micronsat 3.6, 4.5, 5.8, and 8 microns

Each of the four detector arrays in the Each of the four detector arrays in the camera are 256 x 256 pixels in sizecamera are 256 x 256 pixels in size

two two short-wavelengthshort-wavelength channels are channels are imaged by composite detectors made imaged by composite detectors made from from indiumindium and and antimonyantimony

long-wavelengthlong-wavelength channels use silicon channels use silicon detectors that have been specially treated detectors that have been specially treated with with arsenicarsenic

Spitzer's Infrared SpectrographSpitzer's Infrared Spectrograph provides both provides both highhigh- and - and low-resolutionlow-resolution spectroscopy at mid-infrared wavelengths spectroscopy at mid-infrared wavelengths has has fourfour separate modules: separate modules: ……a low-resolution, short-wavelength mode covering the a low-resolution, short-wavelength mode covering the 5.3-14 micron5.3-14 micron interval; interval;……a high-resolution, short-wavelength mode covering a high-resolution, short-wavelength mode covering 10-19.5 microns10-19.5 microns;;……a low-resolution, long-wavelength mode for observations at a low-resolution, long-wavelength mode for observations at 14-40 microns14-40 microns;;……a high-resolution, long-wavelength mode for a high-resolution, long-wavelength mode for 19-37 microns19-37 microns

Each module has its own entrance slit to let infrared light inEach module has its own entrance slit to let infrared light in

shorter-wavelength silicon detectors are treated with shorter-wavelength silicon detectors are treated with arsenicarsenic; ; the longer-wavelength silicon detectors are treated with the longer-wavelength silicon detectors are treated with antimonyantimony

Spitzer's Multiband Imaging Spitzer's Multiband Imaging PhotometerPhotometer

has three detector arrayshas three detector arrays

……aa 128 x 128 array for imaging at 128 x 128 array for imaging at 24 24 micronsmicrons is composed of is composed of siliconsilicon, , specially treated with specially treated with arsenicarsenic

……aa 32 x 32 array for imaging at 32 x 32 array for imaging at 70 70 micronsmicrons

……a 2 x 20 array for imaging at a 2 x 20 array for imaging at 160 160 micronsmicrons both use both use germaniumgermanium, , treated with treated with galliumgallium

32 x 32 array will also take spectra 32 x 32 array will also take spectra from from 50 - 100 microns50 - 100 microns

MIPS field of view varies from MIPS field of view varies from about about 5x5 arcmin5x5 arcmin at the shortest at the shortest wavelength to about wavelength to about 0.5x5 arcmin0.5x5 arcmin at the longest wavelength at the longest wavelength

Spitzer's CTA Outer ShellSpitzer's CTA Outer Shell

made up ofmade up of::

……a dust cover, outer shield a dust cover, outer shield (cooled by helium vapor)(cooled by helium vapor)

……thermal shields (which block thermal shields (which block radiation from space)radiation from space)

……solar panelssolar panels

shell keeps exterior heat from shell keeps exterior heat from reaching the telescope and reaching the telescope and instuments by radiating it out instuments by radiating it out into cold spaceinto cold space

Lyman Spitzer, Jr.Lyman Spitzer, Jr.

one of the 20th century's great one of the 20th century's great scientists scientists

made major contributions in made major contributions in the areas of the areas of stellar dynamics, stellar dynamics, plasma physics, thermonuclear plasma physics, thermonuclear fusion, and space astronomyfusion, and space astronomy

was the was the first person to propose first person to propose the idea of placing a large the idea of placing a large telescope in spacetelescope in space and was and was the driving force behind the the driving force behind the development of the Hubble development of the Hubble Space Telescope. Space Telescope.

The beginning of the end, Just long enough to keep you running,and why?Heaven only knows!

The beginning, of the end,the beginning of the end,

It's all a vicious circle and the race is run again.