Mars 2020 is NASA’s next flagship mission to the Red Planet. It has four main objectives: to determine whether life ever arose on Mars; to characterise the climate of Mars; to characterise the geology of Mars; and to prepare for human exploration.
The Mars 2020 mission re-uses much of the technology developed for Mars Science Laboratory and the Curiosity rover, with some added features in the Entry, Descent and Landing (EDL) system and some new instrumentation, including:
- Mastcam-Z, a stereoscopic camera system that will have a zoom capacity that should make for some make amazing panoramas.
- MEDA, a suite of weather sensors
- MOXIE, a technology tester experiment to produce oxygen from Martian atmospheric carbon dioxide
- PIXL, an X-ray fluorescence spectrometer to provide detailed chemical analysis
- RIMFAX, a radar for sub surface sounding
- Sherloc, a spectrometer and camera that will map the elemental composition of the Martian surface using a UV laser
- SuperCam, an upgrade of Curiosity’s ChemCam instrument, that will allow researchers to sample the chemistry and mineralogy of rocks and other targets from a distance using a laser.
Mars 2020 has significant European involvement, with the MEDA wind sensors led by CAB-INTA in Spain, the RIMFAX radar led by the Forsvarets Forskningsinstitutt in Norway, the SuperCam Mast led by CNES and CNRS/IRAP in France, and European co-investigators on the Mastcam-Z, MOXIE and SHERLOC instruments.
Today, Mars is cold and dry, with high radiation levels and is generally inhospitable. However, around 3.6 billion years ago, the climate of Mars is thought to have been warm enough to support liquid water and an atmosphere, which raises the possibility that there was once life on Mars. Any life that did arise is likely to have been in very simple form — for billions of years, life on Earth was microbial and we only find complex fossils on Earth dating back 540 million years. Thus, Mars 2020 is not looking for current life on Mars but for evidence of microbial life from when the Red Planet was only about one billion years old.
The choice of sites for the Mars 2020 mission to explore has been narrowed down to eight potential locations that are either near ancient deltas in lakes or near ancient hydrothermal systems. NASA will down-select the final landing site within the next couple of years.
For the Curiosity rover, NASA restricted the choice of landing sites away from lumpy, bumpy geological hazards. This reduced significantly the risks on landing but had the drawback that flat areas are not of particular geological interest. Curiosity landed within Gale Crater – a 154km wide impact crater dating back 3.5-3.8 billion years containing sedimentary deposits. However, the landing site was on a flat patch well inside the crater rim and to the north of Mount Sharp, the central mound. To reach the foot of Mount Sharp, the real area of interest, Curiosity first had to travel several miles. With a top speed on hard-packed flat ground of just 0.14 kilometres per hour, it took a few months before the rover was able to start its main scientific investigations.
For Mars 2020, NASA has updated the EDL system to include Terrain Relative Navigation, which means that – actually during the landing — the spacecraft will identify hazards and deflect its trajectory to the surface. This means that Mars 2020 will arrive at the site of interest and can start collecting scientifically valid samples more-or-less straight away.
Scientists can’t be sure how much the radiation levels on Mars might affect and degrade evidence of ancient biological activity. Thus, a good strategy for finding preserved biomarkers is to collect samples from rocks that have only been recently exposed e.g. scarp areas where wind erosion grinds away at the surface.
The ambition is that Mars 2020 will be the first step in a sample return programme to bring rocks back to Earth for scientific analysis. The rover will carry out “depot caching”, in which it will collect 30-40 cores (cylindrical samples about the size of a piece of chalk), store each core in a capped tube, and lay them down on the ground for future collection. Rather than just grabbing and laying down samples as the rover goes along, Mars 2020 will first make a survey of the area and prioritise the samples from the most interesting geological areas.
The samples may need to sit on Mars for a decade or more before being collected by a robotic mission (currently planned by NASA for the late 2020s), so the storage tubes will need to protect this valuable scientific cargo from long-term UV exposure and heat degradation. Even at chilly Martian temperatures, thermal effects inside the storage tubes could cause heating of samples to damaging temperatures where biological evidence could be lost. To mitigate this, tubes will be painted with bright white aluminium oxide to keep samples at no more than 10 degrees above surface temperature.
Though films like ‘The Martian’ might lead you to believe everything on Mars gets quickly buried by dust devils, the cores will be deposited in bare, hard-packed areas and are unlikely to experience more than a very light surface dusting of particles. In addition, NASA will take coordinates of the cache and photo document the surrounding area. Detailed images and measurements from the rovers instrumentation of the environment surrounding each core extraction site will be vital during analysis back on Earth to get a thorough understanding of the geology and context for the samples.
Mars 2020 is due for launch in July or August 2020 when Earth and Mars well aligned in their orbits for a short transit time to Mars. For more information on the mission, see: http://mars.nasa.gov/mars2020/mission/overview/
Many thanks to Ken Farley for speaking to us about the mission and the AAS press officer, Rick Feinberg, and Jia-Rui Cook at JPL for organizing the tour of JPL for the DPS-EPSC Joint Meeting media attendees.
Anita Heward, EPSC-DPS Press Officer