By Vedant Mehta
On August 5, 2012, at 10:17 p.m. PDT, NASA’s giant rover Curiosity landed on Mars, the fourth planet in our solar system from the Sun. Curiosity rover is 3 meters long, 2.8 meters wide, and 2.1 meters tall weighing 900 kilograms (around 2,000 lbs). Slowing the giant laboratory down from entry-level hypersonic speeds to near zero and safely landing it on Martian surface was immensely complicated. It required a rocket-powered crane to land the rover on the surface. Curiosity’s primary goal was to determine if Martian soil and climate offered favorable conditions for life in past. The rover contains several instruments on board to understand the planet conditions better. These instruments include spectrometers for material characterization, radiation detectors, cameras for taking pictures (and selfies), and weather sensors.
Now, seven years later, Curiosity has spent approximately 2500 sols (sol = Martian day, which is just over 24 hours of Earth time) on Mars providing insightful discoveries about the planet. During its earlier years, drilling samples showed that Mars had the fundamental elements like carbon, nitrogen, oxygen, hydrogen, phosphorous, and sulfur. Analysis around the Gale Crater, where Curiosity landed, also showed signs of an old lake. These findings suggest that Mars once hosted a suitable environment that could support life.
The Red Planet rover obtains its extreme power from a 4.8 kg plutonium dioxide fuel. The radioactive decay heat from Pu238 is utilized by multi-mission radioisotope thermoelectric generator (MMRTG) to generate electricity which is then used by the rover to power its instruments.
Curiosity is an incredible example where nuclear power has aided cutting-edge missions to explore other celestial bodies. It is beyond doubt that with such high-energy density, nuclear fuel will play an essential role in colonizing Mars. And while it’s not the longest mission, there were other rovers that went longer, I believe Curiosity’s mission will end when the battery and/or the instruments die out (just like Opportunity). Curiosity’s main mission was to see if Mars provided suitable environment to support life in past.
ANS member Vedant Mehta is a Ph.D. student in nuclear engineering at Georgia Tech. Vedant is also part of the ANS Social Media Team.