top of page


Complete each gap with one word.

(1) ____ the launch of Sputnik, the United States had been working on its own capability to launch a satellite. The United States (2) ____ two failed attempts before succeeding with a rocket that carried a satellite called Explorer on January 31, 1958. The team that achieved this first U.S. satellite launch consisted largely (3) ____ German rocket scientists who had once developed missiles for Nazi Germany. Working for the U.S. Army at the Redstone Arsenal, Alabama, the German rocket scientists were led (4) ____ Wernher von Braun and had developed the German V2 rocket into a more powerful rocket, called the Jupiter C, or Juno. Explorer carried several instruments into space for conducting science experiments. One instrument was a Geiger counter for detecting cosmic rays. This was for an experiment operated by researcher James Van Allen, which, together with measurements from later satellites, proved the existence of (5) ____ are now called the Van Allen radiation belts around Earth.

In 1958, space exploration activities in the United States (6) ____ consolidated into a new government agency, the National Aeronautics and Space Administration (NASA). When it began operations in October of 1958, NASA took over what had been (7) ____ the National Advisory Committee for Aeronautics (NACA), and several (8) ____ research and military facilities.

Alternatively, do it in interactive form here:

Causative Form

To study the theory, click here:

Try out what you have learnt by doing the following interactive exercises:

exercise 1

exercise 2

bottom of page