Did you know it takes 8 minutes for light to travel from the sun to earth? Light travels very fast, but the solar system is very, very large. Communicating with robots—and, one day, people—on Mars is tricky because messages can only travel as fast as light waves.

Look at the orbits of Earth and Mars. You can see that sometimes Mars and Earth are closer together and sometimes they are further apart. When Mars and Earth are close, it takes as little as 4 minutes for messages to travel between the planets. But when Mars and Earth are on opposite sides of the sun, it can take 21 minutes! A lot can happen to a robot on an alien planet in 21 minutes. Because communication is so slow between Earth and Mars, Martian robots need to be able to do much on their own, such as navigate around obstacles.

In this activity, you will get a chance to create a simple communication program using mBlock 5 software or the mBlock app.


  • Become familiar with the mBlock 5 software or mBlock app.
  • Write a Codey Rocky program in mBlock software or mBlock app.
  • Run a program on Codey Rocky.
  • Practice troubleshooting when problems arise.