NASA’s Long Duration Exposure Facility is a bus-sized satellite intended to test the effects of low-earth orbit over a long period of time. The satellite was in part designed as a way to collect data on what materials to build space station Freedom out of. It was intended to stay in LEO for only 1 year, but it ended up staying in space for 5 years before it was collected.
The various hazards it either anticipated or discovered included:
- UV exposure
- Atomic oxygen; individual oxygen atom impacts
- Micrometeorite impacts
- Off-gassing in materials, such as paint, which caused gunk to appear
The satellite was also designed to automatically keep a particular orientation while orbiting. The leading side tended to have a bleached appearance due to atomic oxygen impacts.