Long Duration Exposure Facility
The Long Duration Exposure Facility was a NASA 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. 1
The various hazards it either anticipated or discovered included: 1
- 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. 1