Lesson 3: Calculating Speed

Now that we can track position and time, we can determine how fast the ISS is moving. Speed is simply the distance traveled divided by the time it took.

Session Goals

Capture two data points separated by time.
Calculate the Time Delta.
Calculate the Distance between two coordinates.
Compute the average Speed.

The Mission Task

Your task is to measure the speed of the ISS. You will take a reading, wait for a short interval, take another reading, and then perform the necessary physics calculations.

Key Concepts

Speed Formula: Speed = Distance / Time.
If we travel 10 km in 2 seconds, our speed is 5 km/s.
Haversine Formula: A mathematical formula used to calculate the great-circle distance between two points on a sphere (like Earth) given their longitudes and latitudes.
Sampling Rate: How often we take a measurement. If we wait too long, the ISS might move too far for a simple calculation. If we wait too little, the sensor noise might affect accuracy.

Mission Challenge: Compute Velocity

Objective: Calculate the real-time speed of the ISS in km/s.

Instructions:

Calculate time_diff by subtracting time1 from time2.
Calculate distance by calling calculate_distance with the latitude and longitude from pos1 and pos2.
Compute speed by dividing distance by time_diff.
Print the result. Is it close to 7.66 km/s?

Orbit (ISS Tracker)

Provides real-time (simulated) coordinate data.

from astro_pi_orbit import ISS

Usage	Description
iss.get_coordinates()	Returns latitude, longitude, altitude, and timestamp.

Time

Standard Python library for time-related functions.

import time

Usage	Description
time.sleep(seconds)	Pauses execution for the specified number of seconds.

Math

Mathematical functions for calculations.

import math

Usage	Description
math.radians(degrees)	Converts degrees to radians.
math.sin(x), math.cos(x)	Trigonometric functions.

Mission Control Interface

Output Terminal

Ready to execute...