conjunctions.py

import re
import requests
from skyfield.api import Topos, Loader, wgs84
from skyfield.timelib import Time
from skyfield.sgp4lib import EarthSatellite

# Load the TLE data from Celestrak
def get_tle_data(url):
    response = requests.get(url)
    response.raise_for_status()
    return response.text.splitlines()

satellites_url = 'https://www.celestrak.com/NORAD/elements/stations.txt'
starlink_url = 'https://www.celestrak.com/NORAD/elements/starlink.txt'
satellites_tle = get_tle_data(satellites_url)
starlink_tle = get_tle_data(starlink_url)

load = Loader('.')
ts = load.timescale()

def load_tle_from_lines(lines):
    satellites = {}
    for i in range(0, len(lines) - 2, 3):
        name, line1, line2 = lines[i:i + 3]
        satellite = EarthSatellite(line1, line2, name, ts)
        satellites[satellite.model.satnum] = satellite
    return satellites

satellites = load_tle_from_lines(satellites_tle)
starlinks = load_tle_from_lines(starlink_tle)

# Find all Starlink satellites that match the pattern STARLINK-300XX
starlink_pattern = re.compile(r'STARLINK-300\d\d')
matched_starlinks = [sat for sat in starlinks.values() if starlink_pattern.match(sat.name)]

# Set the starting date and time for checking conjunctions
from datetime import datetime, timedelta

# Calculate the distance between two satellites in kilometers
def distance_between(sat1, sat2, t):
    sat1_position = sat1.at(t).position.km
    sat2_position = sat2.at(t).position.km
    return sum((p1 - p2) ** 2 for p1, p2 in zip(sat1_position, sat2_position)) ** 0.5

# Define the threshold for a conjunction (in kilometers)
conjunction_threshold_km = 5.0

# Generate a list of times to check for conjunctions (every minute)
start_time = datetime(2023, 2, 28, 0, 0)
end_time = datetime(2023, 3, 17, 0, 0)
time_range = [start_time + timedelta(minutes=i) for i in range(((end_time - start_time).days * 24 * 60) + 1)]

# Find conjunctions
for check_time in time_range:
    t_check = ts.utc(check_time.year, check_time.month, check_time.day, check_time.hour, check_time.minute)
    for starlink in matched_starlinks:
        for sat in satellites.values():
            distance_km = distance_between(sat, starlink, t_check)
            if distance_km < conjunction_threshold_km:
                print(f'Conjunction between {sat.name} and {starlink.name}:')
                print(f'   Distance: {distance_km:.2f} km')
                print(f'   Time (UTC): {t_check.utc_strftime()}')