Complex sentence: Due to rushed Deadlines, poor design and a fundimental lack of understanding of the technology the NERVA booster is fired successfully only once, when restart is attempted in orbit the device explodes, irradiating the ship and the astronauts.
Split into simpler sentences: Due to rushed deadlines, poor design and a fundamental lack of understanding of the technology disaster strikes. When restart is attempted in orbit the device explodes, irradiating the ship and the astronauts.