What’s the weather like today – on Mars?

Common question. New planet. It’s April and in the Gale Crater, where the Curiosity rover is currently exploring, that means early autumn temperatures: highs around 10°F and lows less than -100°F reported from its Rover Environmental Monitoring Station (REMS). In addition to air and ground temperatures around the rover, other measurements include atmospheric pressure, humidity and ultraviolet radiation at the Martian surface. The air pressure is a very consistent 850 Pa or about 84% of the normal atmospheric pressure at sea level on Earth.

In contrast, when the Mars Environmental Dynamics Analyzer (MEDA) system aboard NASA’s newly arrived Perseverance rover provided its first weather report from the Jezero Crater on Mars, temperatures dropped from -4°F to -14°F within 30 minutes.

Weighing about 12 pounds (5.5 kilograms), MEDA has sensors to record dust levels, wind (both speed and direction), pressure, relative humidity, air temperature, ground temperature and radiation (from both the Sun and space). To conserve limited solar power (up to 17 watts when operating), MEDA’s system wakes itself up every hour, records and stores data, then goes back to sleep independently of rover operations. Measurements are taken both day and night.

MEDA’s dust and radiation sensor in laboratory evaluation. Source: NASA

With 2,300 miles (3,700 kilometers) separating the Jezero Crater from the Gale Crater, the difference from MEDA to REMS measurements provide some interesting contrasts. For example, one concurrent set of measurements indicated that radiation and dust sensors showed Jezero was experiencing a cleaner atmosphere than Gale Crater. However, on Earth it’s over 2,000 miles from Chicago to Los Angeles on Route 66, and we know how different the weather in those two locations is.

The extremely cold and thin Mars atmosphere is being closely monitored for the historic launch of the Ingenuity Mars helicopter, the first powered, controlled flight on another planet.