Mars geologist preps for historic drilling
Perseverance to drill first hole ever to sample Martian rock Metal Tech News – August 4, 2021
Last updated 8/10/2021 at 3:48pm
A year after embarking on its 292.5-million-mile journey to Mars, NASA's Perseverance rover is readying to collect its first Martian rock sample.
Since its February arrival, the robotic geologist and its helicopter sidekick Ingenuity have been exploring the deepest and most ancient layers of exposed bedrock across a 1.5-square-mile patch of the 28-mile-wide Jezero Crater, which was a large lake when Mars was still a water planet.
After carrying out this reconnaissance, Perseverance is preparing the target for a historic first drill hole at Crater Floor Fractured Rough, a collection of pale-colored "paver stones" that NASA scientists believe to be from the original floor of Jezero.
While much of the sampling carried out by the small car-sized rover will be focused on finding definitive evidence of previous Martian life, this site was selected primarily for the geological information it can provide.
"Not every sample Perseverance is collecting will be done in the quest for ancient life, and we don't expect this first sample to provide definitive proof one way or the other," said Ken Farley, a Perseverance project scientist from Caltech. "While the rocks located in this geologic unit are not great time capsules for organics, we believe they have been around since the formation of Jezero Crater and incredibly valuable to fill gaps in our geologic understanding of this region – things we'll desperately need to know if we find life once existed on Mars."
And this geological understanding will make the first hole drilled into Martian rocks a historic event for the Perseverance team, Nasa, and Earth.
"When Neil Armstrong took the first sample from the Sea of Tranquility 52 years ago, he began a process that would rewrite what humanity knew about the Moon," said Thomas Zurbuchen, associate administrator for science at NASA Headquarters. "I have every expectation that Perseverance's first sample from Jezero Crater, and those that come after, will do the same for Mars."
This historic sampling mission is allowing Perseverance to fully exercise its impressive cache of geological tools and instruments.
This toolkit includes:
• SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals), which uses cameras, spectrometers, and an ultraviolet laser to search for organics and minerals.
• WATSON (Wide Angle Topographic Sensor for Operations and Engineering), SHERLOC's photographic assistant that takes close-up color images of rock grains and surface textures.
• PIXL (Planetary Instrument for X-ray Lithochemistry) – A combination of a camera for taking super close-up pictures of rock and soil textures and an X-ray spectrometer to analyze the elemental makeup of the rocks being studied.
These and other instruments are mounted on the end of a seven-foot-long robotic arm that has the brawn to heft them and the dexterity to ensure they are deployed with precision and without damaging the scientific payload.
"That's the main tool the science team will use to do close-up examination of the geologic features of Jezero Crater, and then we'll drill and sample the ones they find the most interesting," said Robert Hogg, Mars 2020 Perseverance rover deputy mission manager.
A more detailed description of the robotic arm and Perseverance's instruments can be read at Perseverance is a well equipped geologist in the April 14, 2021 edition of Metal Tech News.
In preparation for drilling the first hole into Martian rock, Perseverance will place everything necessary for sampling within arm's reach. It will then use its imaging equipment to survey the area and provide NASA's science team more information to pinpoint the very best location to drill the historic hole.
A separate target site in the same area will also be tested for "proximity science."
"The idea is to get valuable data on the rock we are about to sample by finding its geologic twin and performing detailed in-situ analysis," said science campaign co-lead Vivian Sun, from NASA's Jet Propulsion Laboratory in Southern California. "On the geologic double, first we use an abrading bit to scrape off the top layers of rock and dust to expose fresh, unweathered surfaces, blow it clean with our gas dust removal tool, and then get up close and personal with our turret-mounted proximity science instruments SHERLOC, PIXL, and WATSON."
Perseverance's SuperCam and Mastcam-Z instruments on the mast, which looks like rover's head, will also provide scientists with a trove of detailed information about the rocks. The SuperCam laser and spectrometers will analyze the chemical and mineral makeup of the cleaned surface, and Mastcam-Z will capture high-resolution imagery for the earthbound scientists to research until they can have physical mars rocks to study.
Once these pre-drilling preparations are complete, Perseverance will take a sol, or Martian day, off to fully recharge its batteries before using its drill to collect the historic rock sample.
Once recharged, the robotic geologist will be ready to collect, photograph, and analyze a rock sample before prepping it for future transport to Earth.
Much like the mineral exploration geologists here on Earth, the Perseverance has very strict protocols for storing, analyzing, and preparing rock and soil samples for storage.
Much of this work falls onto a robotic arm that serves as a "lab assistant" to the big arm doing the fieldwork. The small arm loads sample tubes into the drill and transfers filled sample containers into an area where they are hermetically sealed and stored.
With the idea of eventually sending these Martian rock and soil samples back to Earth for further study, Perseverance will drop them at a designated cache depot that will be well-documented by local landmarks and precise coordinates.
Scientists are excited about the prospect of being able to study samples collected directly from the Mars surface for the first time ever. They, however, will have to wait a few years to carry out a more thorough analysis of Martian samples in an earthbound lab.
As currently envisioned, a Mars lander carrying a sample collection rover will launch in 2026 and touch down near Jezero Crater in 2028. The fetch rover would pick up the stashed samples and transfer them to a rocket that would be launched to a separate orbiting spacecraft that would shuttle the historic rock samples back to Earth.
As a robotic geologist, astrobiologist, and ambassador at the forefront of NASA's Moon to Mars exploration strategy, Perseverance's mission to characterize the geology and past climate will pave the way for human exploration of the Red Planet.
"We are on the threshold of a new era of planetary science and discovery," said NASA's Zurbuchen.