Extract LightSail data from spacetrack and plot it.

plot_lightsail-data.py

#!/usr/bin/env python3
import json
import datetime
from spacetrack import SpaceTrackClient
import matplotlib.pyplot as plt
import matplotlib.dates as mdates

if __name__ == "__main__":
    # Login
    st = SpaceTrackClient("username", "password")

    # Get data
    data = json.loads(st.tle(norad_cat_id=44420, orderby="EPOCH", format="json"))

    # Initialize arrays
    epoch = []
    eccentricity = []
    mean_motion = []

    # Loop over entries
    for d in data:
        # Convert epoch to datetime
        epoch.append(datetime.datetime.strptime(d["EPOCH"], "%Y-%m-%d %H:%M:%S"))

        # Convert eccentricity and mean motion to floats
        eccentricity.append(float(d["ECCENTRICITY"]))
        mean_motion.append(float(d["MEAN_MOTION"]))

    # Intialize figure with two panels, share the horizontal axis
    fig, (ax1, ax2) = plt.subplots(2, 1, figsize=(15, 8), sharex=True)

    # Set formatting for horizontal axis
    date_format = mdates.DateFormatter("%Y-%m-%d")
    fig.autofmt_xdate(rotation=0, ha="center")

    # Plot eccentricity
    ax1.plot_date(epoch, eccentricity, linestyle="-")
    ax1.xaxis.set_major_locator(mdates.MonthLocator())
    ax1.xaxis.set_major_formatter(date_format)
    ax1.grid()
    ax1.set_ylabel("Eccentricity")
    ax1.set_title("LightSail-A orbital parameters")

    # Plot mean motion
    ax2.plot_date(epoch, mean_motion, linestyle="-")
    ax2.xaxis.set_major_locator(mdates.MonthLocator())
    ax2.xaxis.set_major_formatter(date_format)
    ax2.grid()
    ax2.set_ylabel("Mean motion (revolutions/day)")

    plt.tight_layout()
    plt.savefig("lightsail.png", bbox_inches="tight")