Orbital mechanics

Let's say you are the program manager of a very large, complex system. Perhaps it's an aircraft, or a building, or a communications network. Your system is valued at over US $500 million. Could you imagine being told that you won't ever be able to maintain it? That, once it's operational, it will never be inspected, repaired, or upgraded with new hardware? . Welcome to the world of satellite building. After a satellite is launched, it is on a one-way journey to disrepair and obsolescence, and there is little anyone can do to alter that path. Faults (which are called anomalies in the space business) can only be diagnosed remotely, using data and inferential reasoning. Software fixes and upgrades may be possible, but most mechanical anomalies can't be corrected. And hardware can't be replaced, which means that even if a satellite is operating well, it could lose its state-of-the-art status just a few years into a typical 15-year lifetime.