An artist's rendering of the SuperCam instrument aboard the next generation Mars rover scheduled to visit the Red Planet in 2020. Image credit: NASA
Last week, NASA's Mars 2020 mission reached a developmental milestone known as Key Decision Point C, having passed a meticulous technical review of its design. NASA has given permission (and funding) for engineers at Jet Propulsion Laboratory (JPL) in California to begin "cutting metal," and the next four years will be spent on the fabrication and assembly of the spacecraft and its payload of scientific instruments. Barring any unexpected technical problems, it will launch in summer 2020, as its name suggests, and land in February 2021. Its mission is to find evidence of past life on Mars.
CURIOSITY 2: THE NEXT LOGICAL STEP
An artist concept image of where seven carefully selected instruments will be located on NASA’s Mars 2020 rover. The instruments will conduct unprecedented science and exploration technology investigations on the Red Planet as never before. Image credit: NASA
The Mars 2020 rover is based on the same design as the 2012 Curiosity rover, though it boasts a new suite of onboard instruments chosen to satisfy different science objectives. Among other things, Curiosity is a habitability mission seeking to answer the question: "Could Mars have ever supported life?" That question has been answered: yes. Mars 2020, therefore, takes the next logical step, and seeks to find that life. To do this, the nuclear-powered rover will examine rocks, soil, and air, and in the process map and study elements, minerals, and organic compounds. The rover will also host a high-resolution camera with panoramic and zoom features—an upgrade to that found on Curiosity. A ground penetrating radar will give scientists their first look beneath the surface of Mars, creating what NASA describes as "sonogram-like images" of subsurface structures. (Fingers crossed for dinosaur bones.) NASA also hopes to send a helicopter drone to scout ahead of the rover, searching for interesting geology and safe routes.
Another of Mars 2020's objectives will be the caching of Martian soil and rock samples. A collection arm will gather interesting materials, which will be examined and then inserted into small tubes. Once a requisite number of samples have been collected, the rover will deposit the tubes in select locations for some future rover to gather, package, and shoot into space. A different spacecraft will then bring the sample box home for scientists to study in terrestrial laboratories.
Mars 2020 is also part of NASA's "Journey to Mars" initiative, whose eventual goal is the landing of humans on the red planet. The rover will carry a device called MOXIE, which is short for "Mars OXygen In situ resource utilization Experiment." (They really had to stretch for that acronym.) MOXIE will produce oxygen from carbon dioxide through a method called solid oxide electrolysis. If the experiment is a success, creating highly pure oxygen, NASA intends to send a much larger version of it to Mars, where it will begin producing and storing a massive supply of air for astronauts to breathe on some future visit in the 2030s, as well as to provide the rockets with liquid oxygen for the journey home.
The rover is as of yet unnamed. In the coming years, NASA will solicit naming suggestions from the public as it did with Curiosity.
SEVEN MORE MINUTES OF TERROR
Because the rover design for Mars 2020 is based on Curiosity, NASA will essentially repeat its famed 2012 entry, descent, and landing (EDL). As seen in the "Seven Minutes of Terror" video, the spacecraft will enter the Martian atmosphere at 13,000 mph before decelerating to 900 mph, adjusting course using its thrusters. It will then deploy a supersonic parachute and drop its heat shield. Once in position and flying at 200 mph, it will pop away its back-shell and a sky crane will fire up its rockets for a powered, gentle descent. Once it reaches 20 meters above the Martian surface, it will begin lowering to the ground a tethered rover. After touchdown, the tether will detach and the sky crane will rocket away so as to avoid damaging the rover.
JPL has added a few new features to the Mars 2020's EDL suite. It can deploy its parachute with greater precision. Rather than relying on velocity (i.e., "I'm slow enough and will therefore deploy my chute"), it will use terrain-relative navigation (e.g., "I risk overshooting my target and will therefore deploy my chute a bit earlier than expected," or vice versa). This decreases the variability of the landing ellipse by 50 percent, meaning the rover mission will start right where scientists intend. The EDL also includes terrain-relative navigation systems. After the parachute is deployed and the heat shield is jettisoned, an onboard camera will examine the ground and use an orbital map to figure out where it is over Mars. The sky crane can then avoid any hazardous terrain that might be nearby.
This artist's concept shows the sky crane maneuver during Curiosity's descent to the Martian surface. Image credit: NASA/JPL-Caltech
For all previous Mars landings, the drop zone was necessarily big and flat, which is safe for engineers, but boring for scientists. With terrain navigation, Mars 2020 can now aim for scientifically interesting areas that have smaller patches of flat terrain. While a landing area has not yet been determined, sites that were previously rejected for Curiosity can now be considered.
Engineers have also added a suite of cameras to the EDL system. Despite using parachutes to land Sojourner, Spirit, Opportunity, and Curiosity, nobody has ever actually seen a parachute inflate supersonically on Mars. This time, however, cameras will capture the action. In addition, descent cameras will record the ground rushing up to the spacecraft, and rover cameras will be pointed at the sky crane. The upshot is that for the first time, we will have actual, harrowing video of what it's like to land on Mars. The craft will also include a microphone, so we will know what it sounds like as well.
This is a lot to accomplish in four years, though Curiosity solved many of the problems scientists and engineers are facing on Mars 2020. Moreover, because this mission inherits spare hardware from Curiosity, many parts needed are already built and tested. If the mission's name is to be accurate, there is not much room for error. Should the mission fail to meet its launch window, it will take another two years for the solar system to put Earth and Mars back into prime travel alignment.