The Universe in the Infrared
What is the Spitzer Space Telescope,
and how does it work?
Images courtesy NASA/JPL - Caltech
Funded by NASA’s Spitzer Science Center
Outline
NASA’s Great Observatories
Introducing Spitzer
Spitzer’s Launch
Orbit
Naming Spitzer
The Telescope
Instruments
Future IR Telescopes
The Universe in the Infrared
Pilachowski / August 2005 Slide 2
NASA’s Great Observatories
HST 1990
Compton GRO 1991
Chandra 1999
The Universe in the Infrared
Spitzer is the final spacecraft in
NASA's Great Observatories program
Pilachowski / August 2005 Slide 3
Introducing Spitzer
The Spitzer Space
Telescope is a
cryogenically
cooled, infrared
observatory in
space.
Spitzer can study
objects ranging
from our Solar
System to the
distant reaches of
the Universe.
The Universe in the Infrared
Pilachowski / August 2005 Slide 4
Launch
• Launched from KSC on
25 August 2003
• Lifetime:
2.5 years (minimum);
5+ years (goal)
The Universe in the Infrared
Pilachowski / August 2005 Slide 5
Heliocentric Orbit
• Most space telescopes orbit the
Earth
• Spitzer orbits the Sun - trailing
the Earth as it moves around the
Sun
• Spitzer is receding from Earth
at 9.3 million miles (15 million
kilometers) per year
• Spitzer now trails the Earth in
its orbit by about 20 million
miles (~ 32 million kilometers)
• By 2008, Spitzer will be about
56 million miles or 90 million
kilometers away
The Universe in the Infrared
Pilachowski / August 2005 Slide 6
Named for Lyman Spitzer
 Lyman Spitzer was
the driving force
behind HST
 Founded the study
of the interstellar
medium
 Studied interstellar
dust and star
formation
The Universe in the Infrared
Pilachowski / August 2005 Slide 7
Introducing the Telescope
The Universe in the Infrared
Pilachowski / August 2005 Slide 8
Spitzer Specs
Mirror:
85 cm (33.5”) diameter
lightweight beryllium
f/12 curvature
Weight:
Telescope: 851.5 kg
He cryogen: 50.4 kg
N propellent: 15.6 kg
The Universe in the Infrared
Pilachowski / August 2005 Slide 9
Keeping Spitzer Cold
• Telescope operates at
5.5 K
• Why? - Spitzer is itself
a black body radiator,
and must be colder than
the astronomical sources
it detects
• How?
– Heliocentric orbit
– Solar shield/solar cells
– Outer shell insulates
and cools the telescope
The Universe in the Infrared
Pilachowski / August 2005 Slide 10
Keeping Spitzer’s Instruments Even Colder
A tank of liquid helium is used to keep
Spitzer’s instruments and detectors at 1.5 K
The Universe in the Infrared
Pilachowski / August 2005 Slide 11
Spitzer’s Instruments
• IRAC – InfraRed Array Camera
– images at 3.6, 4.5, 5.8, and 8 mm
• IRS – InfraRed Spectrograph
– mid-IR spectroscopy
• MIPS – Multiband Imaging Photometer for Spitzer
– images at 24, 70, and 160 mm
IRS
MIPS
The Universe in the Infrared
IRAC
Pilachowski / August 2005 Slide 12
InfraRed Array Camera (IRAC)
• Built at the Smithsonian
Astrophysical Observatory
• Simultaneous images in four
IR passbands
The Universe in the Infrared
Pilachowski / August 2005 Slide 13
InfraRed Spectrometer
• Built at Cornell University
• Spectroscopy in the mid-IR
The Universe in the Infrared
Pilachowski / August 2005 Slide 14
Multiband Imaging Photometer
for Spitzer (MIPS)
Built at the University
of Arizona
• Three detector arrays
– 128x128 pixel Si:As for 24 mm
– 32x32 pixel Ge:Ga for 70 mm
– 2x20 pixel Ge:Ga for 160 mm
The Universe in the Infrared
Pilachowski / August 2005 Slide 15
Spitzer Focal Plane
Spitzer instruments are
arranged in fixed
locations on the Spitzer
focal plane
The telescope is rotated
to move a particular
science target to the
right position for the
instrument to be used
Other instruments
record data for
“serendipitous” fields
The Universe in the Infrared
Pilachowski / August 2005 Slide 16
Spitzer Operations
What Is Spitzer
Doing Now?
www.spitzer.caltech.edu/about/now.shtml
The Universe in the Infrared
Pilachowski / August 2005 Slide 17
Future Infrared Satellites
2007: Herschel Space
Observatory - a European
Space Agency infraredsubmillimeter mission
planned for 2007 to study
galaxy formation,
interstellar matter, star
formation and the
atmospheres of comets and
planets.
The Universe in the Infrared
2007: Planck Surveyor - European
Space Agency far infraredsubmillimeter mission planned for
2007 to study Cosmic Background
Radiation.
2010: The James Webb
Space Telescope, planned
for launch in about 2011,
is a visible/infrared space
mission to study the early
universe and the
formation of galaxies,
stars and planets.
Pilachowski / August 2005 Slide 18