Today, hundreds of scientists and engineers around the world will see their hopes validated or dashed as NASA announces the selection of the scientific instruments that will be deployed on its next Mars rover, which launches in 2020. The announcement will be made live on NASATV at noon EDT.
You might be surprised that NASA didn’t know which scientific instruments would ride along on the Mars 2020 rover when the mission was first announced in 2012. Unlike smaller missions in which scientists propose the whole package (spacecraft and instrumentation), NASA sets the overall strategic goals of its flagship-class spacecraft and then fields submissions from the scientific community for the actual scientific hardware that will achieve those goals.
For the Mars 2020 rover, NASA convened a Science Definition Team (SDT) to hone the specific scientific goals for the mission. The science definition team’s report, released in July of last year, formally declared that Mars 2020 would search for biosignatures—signs of past or present life—and collect and store samples that could be returned to Earth at some point in the future.
NASA / JPL-Caltech
Artist's Concept of Mars 2020 Rover, Annotated
Planning for NASA's 2020 Mars rover envisions a basic structure that capitalizes on re-using the design and engineering work done for the NASA rover Curiosity, which landed on Mars in 2012, but with new science instruments selected through competition for accomplishing different science objectives with the 2020 mission.
The SDT report goes into great depth about how best the rover should search for biosignatures and for samples to store for Earth return. In service of these goals, and in order to provide a rich scientific bounty while the rover explores the Martian surface, the SDT recommended a focus on petrology, is the composition and distribution of minerals within the rocks. This level of understanding helps scientists understand the preservation potential for biosignatures, how the rocks were altered over time, and provide crucial contextual information for any samples returned to Earth. There are also additional instrumentation reserved for demonstrating technology related to future human landing and exploration needs (Curiosity had a instrument in this vein, the Radiation Assessment Detector, which measured the radiation environment astronauts would face in transit and on the surface of Mars).
Scientists around the world read through this report and eventually submitted fifty-eight proposals for instruments. Each submission is led by a Principal Investigator (PI) marshalling a team of scientists and engineers. These are beefy proposals, totaling many hundreds, if not thousands, of hours of work on behalf of their teams. Essentially, each proposal is one long argument for why this instrument is crucial and deserves to fly to Mars.
It’s not clear how many instruments NASA will select. Staff at its headquarters have spent the previous seven months weighing and evaluating the proposals on a number of factors. Cost is, of course, a major issue. The entire suite of scientific instruments can draw from a pool of about $100 million dollars—significantly less than Curiosity had for its ten instruments.
There are many other factors NASA needs balance in the package of instruments it selects: minimizing engineering risk and complexity; total power usage (the rover will only have about 100-115 V of power available from a battery that must be periodically charged); operating temperatures of hardware; and even the amount of data generated by the science instruments that has to be sent back to Earth in a reasonable timeframe (even with orbiting relay satellites, data comes down from Mars at a slower pace than your 4G smartphone). I do not envy the NASA project managers who had to find just the right balance in all of these factors.
So what to look for today? There will certainly be a camera selected for the mission. Curiosity was originally conceived with independent zoom lenses on each camera eye, later descoped, so perhaps these will make it onto Mars 2020. There is also a big focus on remote sensing of mineralogy, and it will be interesting to see if NASA selects a Raman or IR spectroscopy instrument, or maybe something else entirely. The contributions from the human spaceflight directorate will also be interesting, as rumors have swirled about potential experiments to test a system that would create oxygen from the CO2 in Mars’ atmosphere.
It’s an exciting day for this mission, and a bittersweet one for scientists and engineers, many of which will not see their proposals selected. Humans are endlessly creative and curious, and there will always be more science desired than possible when resources are limited. The ones that do get selected now face six years of building, testing, and integrating their ideas into the rover itself—no easy task.
It’s exciting to see the Mars 2020 rover begin to take shape. And you don’t have to take my word for it, look what a JPL engineer tweeted today, the skeletal frame of the SkyCrane descent stage that will lower the rover onto the surface of Mars:
This mission is moving forward. Within six years Curiosity will have a sister rover on some other part of Mars, advancing our understanding of the red planet. Exactly how she will go about doing this will be revealed at noon EDT today.