The correct answer is B) to explore the last frontier.
What caused scientists such as Robert Goddard, Konstantin Tsiolkovsky, and Hermann Oberth to experiment with rocket technology in the early twentieth century was to explore the last frontier.
The idea of exploration and go beyond our planet attracted many scientists that started to research and experiment with technology to launch rockets and to know more about space and the human possibilities to understand it. For instance, that is the case of American engineer Robert Hutchings Goddard whose research made him invent the liquid-fueled rocket.
The other options of the question were A) to launch of artificial satellites. C) to win their countries in the space race. D) to help their governments to spy their enemies. E) to gain victory in wars.
