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HOME EXPERIMENT 1:�INTERNATIONAL SPACE STATION TRACKING�GROUP MEMBERS:�TALHA AHMED�KHUZEMAH HASSAN QAZI

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BACKGROUND:

THE ISS IS ONE OF MANKIND’S GREATEST ACHIEVEMENT TO THIS DAY. THE ISS HOLDS MUCH SCIENTIFIC VALUE IN CRUCIAL FIELDS LIKE TOPOGRAPHY, MEDICINE, BIOLOGY ETC. TRAVELLING AT ROUGHLY 7.66 KM/S, IT ORBITS THE EARTH APPROXIMATELY 16 TIMES IN 24 HOURS!

PROCEDURE:

  • EXPERIMENTALLY OBSERVE THE ISS AND CAPTURE TWO PICTURES, SET APART BY INTERVAL (ΔT)
  • FOR ANOTHER DATA SET, SHOOT A VIDEO OF THE ISS, TO CHECK, IF ANY, EFFECTS ON THE ACCURACY OF THE RESULTS
  • ANALYZE THE IMAGE ON ‘IMAGEJ’ AND THE VIDEO USING ‘TRACKER’.
  • CALCULATE THE TIME PERIOD AND ORBITAL VELOCITY OF ISS WHILE KEEPING TRACK OF UNCERTAINTIES.
  • COMPARE AND EXPLAIN THE VARIATION BETWEEN THE EXPERIMENTAL VALUES WITH THOSE FROM NEWTONIAN MECHANICS AND REAL VALUES.

OBSERVING THE ISS:

  • USE COMPASS TO OBTAIN THE PREDICTED LINE OF SIGHT OF APPEARANCE AND DISAPPEARANCE
  • MEASURE THE ELEVATION ANGLE, BY UTILIZING THE FACT THAT YOUR CLENCHED FIST STRETCHED OUT AT THE LEVEL OF HORIZON MAKES AN ANGLE OF 10°.

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Data analysis:

  • Use ImageJ to first observe the starting point and find out the distance travelled (d) between the starting

and ending point, during the time interval Δt.

  • Use Tracker to analyze the motion of the ISS, by plotting r (position magnitude) against time (t).
  • Calibration reference point: Width of the ISS is 75 m
  • Calculate angular distance travelled by θ=d/h, where θ=y, h=400km. Calculate beta, alpha, x and ω.
  • Propagate uncertainties using known equations.
  • Calculate the Time Period (T) and Orbital Velocity (V) of ISS with respective uncertainties.

Results:

  • T=(4830 ± 1000)sec , V=(8840 ± 3000) ms^-1 (ImageJ)
  • T=(5851± 5)sec , V=(7302 ± 7) ms^-1(Tracker)

Conclusion/Improvements:

  • Experimental values are close to the real values; however, Tracker gave a much reliable result.
  • Use tripod to get better stability-reduces uncertainty.
  • Use stopwatch to get a better and accurate idea of Δt, this reduces uncertainty.
  • Take picture in an area with less pollution and clear weather to get a better image.
  • Instead of using the width of the ISS as the calibration reference point, using nearby stars for calibration will give a more accurate measure, as their angular size and orientation does not change depending on the observer.

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