Space was always considered the unconquered frontier for mankind. This is because the environment in space is so hostile that even the slightest errors could prevent a return trip to earth. The only way to conquer space is to develop the technology needed to survive in space in earth. The most important craft that has to be developed will be the craft that will carry people to space. The reason is that you will be dealing with extremely large amounts of thrust and g-forces. These factors could be potentially lethal for the people on board.

Furthermore, they have to make sure that the massive engines don't compromise the integrity of the ship's hull. That is why they run the engines past their breaking points. They set up a perimeter of danger flags and watch the engines explode.

Spacecraft are essential to the whole idea of space exploration. However, people who go to space have to be in a self-contained life-support system. Otherwise, they wouldn't have air to breathe, their blood would boil under the pressure, and they won't be able to survive the intense solar radiation. People develop different suits on earth. They test them in different chambers that simulate different events that could affect any of the factors that would determine the life of the person wearing that suit before they sew on the miniature world flag patch.

Once we learn how to conquer space, we will be able to explore the different worlds out there. And we will be able to drive out technological advances even further.