Satellite - picoCTF 2025 Writeup

Given a set of orbital parameters and a time window, find the name of the military vessel that passed closest to a specified research base.

🚩 Challenge Overview

  • Platform/Event: picoCTF 2025
  • Difficulty: Medium
  • Points: 180
  • Solves: 280
  • Category: OSINT
  • Tags: Satellite Tracking, Coordinate Analysis, OpenData, MarineTraffic

📝 Description

Given a set of orbital parameters and a time window, find the name of the military vessel that passed closest to a specified research base.

💡 Solution / Approach

  1. Convert the satellite Two-Line Element (TLE) set into lat/long coordinates using a Python satellite tracking script (pyephem or skyfield).

  2. Pinpoint the exact pass timestamp closest to the coordinates of the base (64.9°S, 63.5°W).

  3. Use historical MarineTraffic or AIS vessel location portals to query ships active in the Antarctic Peninsula within that specific time window.

  4. Identify the vessel: RRS Sir David Attenborough. The flag is the ship’s MMSI number.