Mars Lag

Suppose the rover sends back a signal which NASA scientists review and then send some sort of instruction back to the rover on Mars. If we want to limit the total "lag" time (from the time the rover sends a signal to the time it receives an instruction) to 30 minutes, and it takes the scientists 10 minutes (600 seconds) to review the data, what's the maximum distance between Earth and Mars that will allow that?

Subject: Algebra
Topics: Expressions and Equations
Grades: 6 – 12
Knowledge and Skills:
- Can evaluate expressions by substituting values for variables
- Can simplify expressions using correct order of operations
- Can do basic operations on both sides of an equation in such a way as to preserve the equality

Download Teacher Guide: Mars Lag (PDF)
Download Student Activity: Mars Lag (PDF)

Algebra in the Real World Movie:

Testing the Mars RoverTesting the Mars Rover

Did Mars ever support life? Why did it change so dramatically? Is there any water left? The only way to answer these questions is to analyze the rocks on the Martian surface. And since we can't yet bring those rocks to us, we must send the analysis instruments to Mars--carried on the backs of rovers.
Running time 1:41 minutes.

Watch the Movie