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9 May 2006

Using the Electromagnetic Spectrum

Mark Webster

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9 May 2006

Outline

• The Electromagnetic Spectrum

• Optical Instrument Design

• Visible Light Applications

• Infrared Observations

• Ultraviolet

• X-ray

• Gamma Ray

• Radio Frequency Applications

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9 May 2006

The Electromagnetic Spectrum and its use in Space Instruments

• The Earth’s atmosphere absorbs a large part of the electromagnetic spectrum

• Information about the universe (and the Earth) can be obtained from wavelengths other than light

• The primary advantage of Earth viewing space instruments is field of view, using a geosynchronous orbit to maintain a constant viewpoint and 24/7 operation

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9 May 2006

Optical InstrumentsEngineering Disciplines:

Optical Engineer

Controls Engineer

Mechanical Engineer

Thermal Engineer

Structural Engineer

Electronic Engineer

Software Engineer

Calibration Engineer

Detector Engineer

Program Manager

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9 May 2006

Hubble Space Telescope• 2.4 meter diameter primary

mirror• 0.01 arc sec resolution (a dime

from 500 miles away)• Telescope has a flaw in its

prescription, was given “glasses,” (corrective optics) in the first servicing mission

• Four scientific instruments– Wide Field Planetary Camera 2– Near-Infrared Camera and Multi-

Object Spectrometer– Space Telescope Imaging

Spectrograph– Advanced Camera for Surveys

• Two new instruments to be added on next servicing mission

– WFPC3– Cosmic Origins Spectrograph

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9 May 2006

Pictures from HubbleEagle Nebula-Birthplace of Stars

Debris Disk around a star, birthplace of planets

Hubble Deep Field – every point a galaxy

Hubble is the most successful space mission ever

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9 May 2006

Weather and Environment Instruments

Katrina approaches New Orleans

Geosynchronous weather satellites are in orbits that keep them in one spot over the Earth

Low Earth orbit weather satellites are closer in and can take pictures with higher resolution

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9 May 2006

Laser Communications and Science

Visible light can be used for communications between satellites in space using lasers

Visible light lasers can also be used to do science. Calypso will use laser light to measure the properties of aerosols (suspended particles) in the Earth’s atmosphere

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9 May 2006

The Spitzer Space Telescope Looks at the Universe in the Infrared

Black Widow nebula is only visible in the infrared

A massive hot cloud of gas surrounding M82 can only be seen with infrared detectors

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9 May 2006

Infrared Earth Observation

• Infrared Earth Observation also provides additional information:– The picture on the left is made from a long series of infrared observations

of Antarctica that show how much the temperature has changed– The picture on the right shows that actual locations of the fires that are

producing the long plumes of smoke, this information comes from infrared fire channels

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9 May 2006

Ultraviolet

A7785_T104

Flight-Tested CompositeStructure and Kinematic

Mounts from STIS,NICMOS, UVCS, SWAS

UV Nadir RadiometryExtends TOMS, SBUV/2

Data Heritage

UV/VIS Limb RadiometryDemonstrated on

SOLSE/LORE

Electronics and CPU withEstablished Flight Heritage(Mars Pathfinder, Surveyor)

Radiation-TolerantOptical and Electronic Components (HST Programs, UVCS, RME)

Conservative CCDApproach Based on STIS,

SAGE III, and ACS

Calibration TechniquesProven on SSBUV,

TOMS

Grating Spectrometers Proven onSBUV/2 and TOMS

Crosstrack

FlightNadir

The Ozone Mapping and Profiling Spectrometer will use ultraviolet light to look at the Earth’s ozone

The Ozone hole over Antarctica as it appears in ultraviolet light

The Aurora Borealis can be seen using ultraviolet light even in the day time

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9 May 2006

X-Ray

The Crab Nebula pulsar as it appears to the x-ray sensors on Chandra

The Chandra X-ray observatory

The sun as it appears in X-ray wavelengths

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9 May 2006

Gamma Ray Observations

• The Compton Gamma-Ray Observatory carried 4 instruments, all of which detected gamma rays of various energy levels indirectly

• The image was created by measuring the intensity of gamma rays as the spacecraft was pointed in all directions

• NASA de-orbited the observatory in 2000 after a gyro failed

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9 May 2006

Radio Frequency Antennas and Applications (Looking Up)

Green Bank Radio Telescope

Very Large Array

Radio Image of the Crab Nebula

Hydrogen 21cm Image of the Milky Way

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9 May 2006

Radio Frequency Antennas and Applications (Looking Down)

Space Shuttle Radar Topography Mission

Satellite Radar image of rainfall intensity in Katrina

SRTM image of the Crater Highlands region of Tanzania

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9 May 2006

Specialty Antennas for Communications

Mars Rover High Gain Phased Array Antenna

Backpack antennas

Phased Array Antenna for the Navy

Conformal Antenna for Aircraft