An engineer working on NASA’s Mars 2020 mission uses a solar intensity probe to measure and compare the amount of artificial sunlight that reaches different portions of the rover. To simulate the Sun’s rays for the test, powerful xenon lamps several floors below the chamber were illuminated, their light directed onto a mirror at the top of the chamber and reflected down on the spacecraft. The data collected during this test will be used to confirm thermal models the team has generated regarding how the Sun’s rays will interact with the 2020 rover while on the surface of Mars.