Frequently Asked Questions | Home | Q. Why do passes for the Shuttle and ISS sometimes appear on the special pages for these two bright satellite, but not on the "All satellites" page? A. The reason is because we have a lower elevation limit of just 10° for the Shuttle and ISS because they are so bright and can be seen closer to the horizon. The "All satellites" page, however, has an elevation cut-off of 20°, because most satellites are difficult to spot lower than this. So if an ISS pass reaches a maximum elevation of 15°, it will appear on the ISS passes page, but will be missing from the "All sats" page because it doesn't achieve the required minimum elevation.   Developed and maintained by Chris Peat, Heavens-Above GmbH Please read the updated FAQ before sending e-mail. Imprint.