Complex sentence: On flight day 14, Discovery was scheduled to land at Kennedy Space Center at 19:04 EDT (23:04 UTC) which was postponed due to weather conditions, the second opportunity at 20:40 EDT (00:40 UTC) was also postponed due to weather conditions.
Split into simpler sentences: On flight day 14, "Discovery" was scheduled to land at Kennedy Space Center at 19:04 EDT (23:04 UTC). The landing was postponed due to weather conditions, and the second opportunity at 20:40 EDT (00:40 UTC) was also postponed due to weather conditions.