A SEMINAR ON

HUBBLE SPACE TELESCOPE

PRESENTED BY:HARI OM

ELECTRONICS & COMMUNICATIONREG NO-030907133

SECTION-CROLL NO.– 123

CONTENTS

• Overview• Spacecraft System• Operation• Parts• Outer structure• Pointing control system• Optical assembly• Scientific instruments• Colours & filters• Application fields• Features• Limitations• Conclusion• References

OVERVIEW

• Hubble—a space telescope• 600km above earth• Excellent pointing precision,powerful

optics,state of the art instruments• Designed -1970s & launched-1990• Moduler design• Goal—knowledge of our cosmic roots

SPACECRAFT SYSTEM

• POWER• COMMUNICATIONS• STEERING-To remain fixed on an object HST has three

onboard systems:• Gyroscopes-Sense small to large motions• Reaction Wheels-Move the telescope• FGS-Sense fine motion

• COMPUTING• STRUCTURE

OPERATION

INTERNAL OPERATION

• Electronic eyes• Cameras--collect light with electronic

detectors• Spectrographs—separate starlight into

rainbow of colours• Mirrors to focus & magnify light

PARTS

OUTER STRUCTURE

• Solar arrays(2)—12m in length,2400 watts• Communication antennae(2)—transmit

information to TDRSS• Computer support systems module—for

communications,navigation,power management,etc.

• Electronic boxes—houses much of the electronics

• Aperture door—just like camera’s lens• Light shield—shaft for blocking surrounding light• Pcs—for pointing towards the target

POINTING CONTROL SYSTEM(PCS)

PCS CONT…

• Fine guidance sensor(3)• Coarse sun sensor(2)• Magnetic sensing system• Rate sensor unit(2)• Fixed head startrackers(3)—electro-

optical detector• Reaction wheel actuators(4)• Magnetic torquers(4)

OPTICAL ASSEMBLY

Primary mirror—2.4m in diameter,concave shapeSecondary mirror—0.3m in diameterFocal plane—for examining the light

SCIENTIFIC INSTRUMENTS

• AXIAL BAYS(4)-Four instruments aligned with the main opticalaxis & are mounted just behind the primary mirror.

• 1>ACS--wide field of view,better light sensitivity• 2>NICMOS—infrared instrument• 3>STIS—separates light into component wavelengths• 4>COSTER—for correction of spherical aberration• WFPC2(Wide Field/Planetary Camera 2)-It is

responsible for taking nearly all of HUBBLE’s famous pictures

• FINE GUIDANCE SENSORS(3)-It measures relative positions,providing data to the spacecraft’s targeting system

LIGHT & FILTERS

COLOUR AS A TOOL

FEATURES

• 3 observations/hour• Each observation requires 100 computer

functions• 2 observations at a time• 100,000 instructions/week• Generates 10 billion bits of scientific data/week• Can move 90 degrees/15 minutes• 17,000mph around the earth

APPLICATION FIELDS

• Best view of mars • Proof of black holes• Quasars—active galactic

nuclei in distant galaxies• Gamma rays origins• The expanding universe• The birth of stars• The death of stars• Comet collision• Auroras & electricity

LIMITATION

• Can’t observe the sun—intense light & heat

• Can’t observe mercury or venus• Can’t observe some stars—too bright• Orbit of HST—target obstructed by earth• Van allen radiation belt—charged particles

from solar winds trapped by earth’s magnetic field

CONCLUSION

Despite its flawed early history, the HST has performed well, yielding much scientific data and beautiful images.

However, the HST will not last forever. Plans are underway for a new space telescope, called the Next Generation Space Telescope (NGST). NGST will be

even more sensitive than HST and provide better images of even more distant objects.The age of optical space telescopes started by HST promises to revolutionize

astronomy as much or more than Galileo's first use of the telescope did long ago.

REFERENCES

• http://hubble.nasa.gov• http://hubblesite.org• http://heritage.stsci.edu/2000/01• http://science.howstuffwoks.com

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