ISS Tracker

Project Objective

The objective of the ISS Tracker project is to create a Flask-based application for real-time tracking and analysis of the International Space Station's (ISS) position and velocity. The primary script downloads live data from NASA's public data repository, parses the XML-formatted data, and calculates various metrics such as the instantaneous speed and geoposition of the ISS at the current time.

System Architecture

This system architecture diagram illustrates the components and interactions within the project. It depicts the user's interaction with the system, the virtual machine hosting the Docker container, and the containerized Flask app which handles the different. This diagram provides a visual overview of the project's structure and workflow, facilitating understanding of its functionality and components.

Contents

• Dockerfile: Defines the environment for containerizing the Python script.
• docker-compose.yml: Docker Compose configuration file.
• iss_tracker.py: Main Python script for tracking and analyzing ISS data.
• requirements.txt: Specifies the required Python packages.
• test/: Directory containing unit tests.
  • test_iss_tracker.py: Unit tests for testing the functionality of iss_tracker.py.
• diagram.png: Software diagram representing components of the project.
• README.md: Instructions and information about the project.

Instructions

1. Accessing the Data

The ISS data is retrieved from NASA's public data repository. To access the data, you can use the following URL: ISS Data. This URL provides an XML file containing the ISS coordinates and velocity information. In the file, ISS state vectors in the Mean of J2000 (J2K) reference frame are listed at four-minute intervals spanning a total length of 15 days.

2. Building the Container

To build the Docker container for the ISS Tracker, follow these steps:

1. Make sure you have Docker installed on your system. If not, download and install Docker from the official Docker website.

2. Navigate to the directory containing the Dockerfile and the Python scripts (iss_tracker.py and test_iss_tracker.py) using the terminal or command prompt.

3. Run the following command to build the Docker image and get the Flask app running in the background:

   docker-compose up -d

   This command builds the Docker image iss_tracker with the tag latest and runs it in the background.

4. Wait for Docker to complete the build process. Use docker docker ps -a to ensure that the iss_tracker container is running on port 5000.

The Flask app is now ready to use. You can confirm that it was built successfully by running docker images to list all available images on your system.

3. Running Unit Tests on the Docker Container

If you wish to run unit tests to ensure the functions in the script work, you can run the following command to access the container's shell:

docker exec -it iss_tracker /bin/bash

After the unit tests are done running, you can exit the container's bash shell by typing exit or pressing Ctrl+D.

4. Accessing the Routes

Once the Docker container is running, you can access various routes in the ISS Tracker app using curl commands. The routes below enable you to interact with different aspects of the ISS Tracker app and retrieve relevant information. Here are the available routes and their descriptions:

4.1. /now

• Method: GET
• Description: Returns information about the closest epoch to the current time, along with the instantaneous speed and geoposition.

4.2. /epochs

• Method: GET
• Description: Returns the entire dataset.

4.3. /epochs?limit=int&offset=int

• Method: GET
• Description: Returns a modified list of Epochs given query parameters limit and offset. It allows you to retrieve a subset of the data.

4.4. /epochs/<epoch>

• Method: GET
• Description: Returns state vectors for a specific Epoch from the data set. It provides information about the position and velocity at that particular epoch.

4.5. /epochs/<epoch>/speed

• Method: GET
• Description: Returns the instantaneous speed for a specific Epoch in the data set. It provides the magnitude of the velocity vector at the given epoch.

4.6. /epochs/<epoch>/location

• Method: GET
• Description: Returns latitude, longitude, altitude, and geoposition for a specific Epoch in the data set. Note that geoposition may return "Address Not Found". Oftentimes, this happens if the ISS is over an ocean at the specified epoch, as the GeoPy library does not return an address if that is the case.

4.7. /comment

• Method: GET
• Description: Returns the 'comment' list object from the ISS data.

4.8. /header

• Method: GET
• Description: Returns the 'header' dictionary object from the ISS data.

4.9. /metadata

• Method: GET
• Description: Returns the 'metadata' dictionary object from the ISS data.

These routes provide comprehensive access to the ISS Tracker app's functionalities and data.

5. Clean Up

Do not forget to stop and remove the container once you are done interacting with the Flask microservice using:

docker-compose down

You can make sure the container has been stopped and removed by running:

docker ps -a

This process ensures resource efficiency and prevents conflicts in subsequent container executions.

Interpreting the Output

The output of the ISS Tracker script provides information about the ISS's position and velocity at various epochs. It allows users to track the ISS's movement, analyze its speed, and understand its current state. The output can be interpreted to gain insights into the ISS's orbit and trajectory.

Acknowledgments

The ISS Tracker project utilizes data provided by NASA's public data repository. The README content, comments in the code, and unit test examples were created with the assistance of ChatGPT, an AI language model developed by OpenAI. The geodetic calculations were verfied by an online tracker.