What does opening a luxury hotel have in common with sending humans to space? You need to think of every little detail, from the food to the curtains, and even minute details such as what kind of soap to provide for the guests. NASA engineers work countless hours and leave no stone unturned to ensure their astronauts with the safest most comfortable trip possible.
One of the most significant things they needed to think of was the fire detector. You know because no one likes a fire in space. The modern fire detector you have in your house today is the direct result of NASA engineering.