Complex sentence: It is now believed that the accelerometer controlling the parachute's pyrotechnics was installed backwards--a similar defect affected the "Genesis" probe's sample return capsule when it returned to Earth in September 2004, causing the capsule to crash in the Utah desert.
Split into simpler sentences: It is now believed that the accelerometer controlling the parachute's pyrotechnics was installed backwards. A similar defect affected the "Genesis" probe's sample return capsule when it returned to Earth in September 2004, causing the capsule to crash in the Utah desert.