public List<ArtificialSatellite> getArtificialSatellites() {
        List<ArtificialSatellite> returnedSatellites = new ArrayList<ArtificialSatellite>();

        for (Satellite satellite : satellites) {
            if (satellite.getClass() == ArtificialSatellite.class) {
                returnedSatellites.add((ArtificialSatellite) satellite);
            }
        }
        return returnedSatellites;


    }