Perseverance is within the strategy of amassing the primary pattern on Mars that would ultimately be returned to Earth
On February 18, 2021, NASA’s Perseverance rover landed in Jezero Crater on Mars. Like its predecessor Curiosity, a member of NASA’s Mars Exploration Program (MEP), Perseverance’s goal is to look for evidence of possible life on Mars (past and present). An important part of this mission will be the first ever sample return on Mars, in which samples collected by Perseverance will be cached for later retrieval and return to Earth.
For the past five months, NASA mission controllers have continued to drive the rover from its Octavia E. Butler Landing Site and test flights with the Ingenuity helicopter. NASA is in the process of making final preparations for Perseverance to collect its first sample of Martian rocks. This historic premiere is expected to begin at the end of the month or early August and culminate with the return of samples to Earth by 2031.
These rocks will come from an area known as the Cratered Floor Fractured Rough, a 4 km2 (1.5 square miles) piece of crater floor that may contain the deepest and oldest layers of Jezero’s exposed bedrock. These rocks will also be the most significant sample return since the Apollo astronauts brought rocks from the moon. These samples still teach us things about the formation of the earth-moon system and the evolution of the solar system.
Freeze frame from the interactive map with the location of the Perseverance rover and the Ingenuity helicopter. Photo credit: NASA / JPL-Caltech
Thomas Zurbuchen, Associate Administrator for Science at NASA Headquarters, said in a recent NASA press release:
“When Neil Armstrong took the first sample from the Sea of Calm 52 years ago, he began a process that would rewrite human knowledge about the moon. I assume the first Perseverance sample from Jezero Crater and the following ones will do the same for Mars. We are on the cusp of a new era in planetary science and discovery. “
This time, getting the first sample of Martian rocks will take about 11 days, compared to the 3 minutes and 35 seconds it took Armstrong to get the first moon sample. Unlike the Apollo astronauts, Perseverance has to receive instructions from mission controllers with a delay of 4 to 24 minutes. Similarly, the process takes time as it is based on the most complex mechanism ever sent into space, the Sampling and Caching System (SCS).
The sequence begins with the rover placing whatever it needs from the SCS within range of the 2 m (7 foot) robotic arm. An image survey will follow so the NASA science team can determine where exactly it will take the first sample and a second destination in the same area for what is known as “proximity science”. Vivian Sun, the scientific co-director of NASA’s Jet Propulsion Laboratory (JPL), said in a recent NASA press release:
“The idea is to get valuable data on the rock we want to sample by finding its geological twin and doing a detailed in-situ analysis. In the geological double we first scrape off the top layers of rock and dust with a grinding chisel to expose fresh, unweathered surfaces, blow them clean with our gas dust removal tool and then come up close with our device mounted on the tower, proximity science instruments SHERLOC, PIXL and WATSON. “
Once the samples are obtained, Perseverance will use its collection of advanced scientific instruments to study them in stunning detail to learn more about their composition. These include the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) instrument, which looks for evidence of organic molecules that form in the presence of water and that could be an indication of life.
This instrument is supported by the Wide Angle Topographic Sensor for Operations and Engineering (WATSON), a color camera for close-ups of rock grains and surface structures. There’s also the Planetary Instrument for X-ray Lithochemistry (PIXL), which uses an X-ray spectrometer to identify chemical elements on a tiny scale. Perseverance will also use its SuperCam and Mastcam-Z instruments (both on the rover’s mast) to survey the local rocks and soil.
The SuperCam works by firing a laser at the surface of rocks and soil to create a small cloud, which it then examines with cameras and spectrometers to look for signs of organic compounds. Meanwhile, the Mastcam-Z takes high-resolution images and videos of samples for a more detailed examination. Together, these five instruments will enable unprecedented analysis of geological material on the construction site.
Once the pilot hole research is complete, the mission team will give the rover a full Martian day (or sol) to charge its batteries for sampling. This begins the next day and begins with the sample handling arm inside the Adaptive Caching Assembly (ACS) taking and heating a sample tube, inserting it into a core drill, and then transferring both to a rotary percussive drill on the Perseverance robotic arm.
The drill fills the tube with a core sample, then transfers it and the core drill back into the ACS for measurement, photography, hermetic sealing and storage. Once all of the tubes are filled, they will be left in a cache that could be picked up by a joint NASA-ESA Mars Sample Return (MSR) mission, including an orbiter, lander, rover, and launcher – scheduled for early 2026.
The next time these samples would be observed in a clean room facility on Earth, where scientists would study them with instruments far too large to be sent to Mars on board a spacecraft. However, as stated by Perseverance Project scientist Ken Farley (a WM Keck Foundation Professor of Geochemistry at Caltech), nobody expects the samples to contain perfectly preserved fossilized remains of ancient life:
“Not every sample that Perseverance collects is conducted in search of ancient life, and we don’t expect this first sample to provide definitive evidence in one way or another. While the rocks in this geological unit aren’t great time capsules for organics, we believe they have existed since the Jezero Crater was formed and are incredibly valuable in filling gaps in our geological understanding of this region – things we do urgently need to know when we discover that there was once life on Mars. “
Nonetheless, having rock and soil samples from Mars available for analysis here on Earth will be invaluable. Like the Apollo lunar rocks, generations of scientists will be able to study them with increasingly sophisticated instruments to learn more about the formation and evolution of Mars, particularly how it existed from a warmer, more humid environment in which life existed could, to an extremely cold and dry place it is today.
Most importantly, this research will pave the way for manned missions to Mars, where crews of astronauts will spend days or even weeks on the surface studying the geology, climate, atmosphere and surface environment of Mars. Check out this video of the Perseverance Rover’s Sample Caching System, courtesy of NASA JPL:
Further reading: NASA