Complex sentence: Shortly after coming to power in 1971, President Idi Amin announced an impossibly optimistic human spaceflight program, that never progressed beyond an attempt at astronaut training on an obstacle course made up of used automobile tires.
Split into simpler sentences: Shortly after coming to power in 1971, President Idi Amin announced an impossibly optimistic human spaceflight program. This essentially consisted of astronaut candidates being trained on an obstacle course made up of used automobile tires.