Image captured of the Perseverance rover by a camera on its rocket-propelled descent stage, just before the moment of touchdown on Mars. (NASA/JPL-Caltech)
Touchdown! No, it’s not football — unless you imagine a playing field 300 million miles long and a fiery 25,000 mph end-zone plunge.
The ball in play is NASA’s Perseverance rover, which successfully touched down on Mars on Thursday at 12:55 p.m. PST, following a seven-month voyage and seven nail-biting minutes blazing through its atmosphere.
Now safely on the ground in Mars’ Jezero Crater, Perseverance is set for what could be a game-changing mission of discovery: a search for signs of past Martian life in the river-deposited sediments of what was probably, long ago, a lake bottom.
First Images from Jezero Crater
Only minutes after landing, Perseverance captured a pair of images with two of its hazard avoidance cameras. The images were promptly relayed back to Earth via NASA’s Mars Reconnaissance Orbiter as it passed over the landing site. The pictures were so fresh that dust lingered in the air, stirred up by Perseverance’s landing stage rockets.
In the hours and days ahead, after the rover’s Mastcam camera is put into service, we should be able to enjoy sweeping, full-color, high-res panoramas from Jezero.
And more. “SuperCam” will use a camera, laser, and spectrometer to probe the chemistry of nearby rocks and soil to search for the spectral fingerprints of organic compounds. “RIMFAX” will send radar pulses into the ground to probe underground structures beneath the rover. And the rover’s long, robotic arm carries an array of instruments, including a rock drill and ultraviolet and X-ray spectrometers to dig into Mars’ mineral secrets.
In Search of Martian Critters
Perseverance is the first mission to look for signs of life on Mars since the Viking landers in the late 1970s. The Vikings carried instruments designed to detect biological activity of any organisms in Mars’ soil, though their findings were inconclusive.
Perseverance will look for evidence of life that may have existed on Mars perhaps billions of years ago, when we know the planet possessed a thicker atmosphere and liquid surface water.
NASA selected the 28-mile-wide Jezero Crater to give Perseverance the best chance of finding signs of life. Long ago, the crater was filled with water, all the necessary ingredients for life were present. If life did thrive there, its chemical and mineral remnants might be found preserved in the rocks of the ancient lake bottom and shoreline.
Jezero Crater also features an extensive deposit of river sediment, washed into the lake from the surrounding terrain at the mouth of a river, now long dry. This adds to the variety and abundance of material that Perseverance will have access to as it crawls around the dry lakebed and shoreline.
On Earth, the muddy sediments at lake bottoms are repositories of biological material: the remains of microbes that lived in the water and mud. Over time, the sediments harden into rock — mudstone or sandstone — and may preserve chemical residues of the long dead critters. On Earth we also find knobby rock formations, called stromatolites, created long ago by microorganisms living in the shallow waters along shorelines.
If scientists can detect and analyze the chemical traces and rock formations left behind by ancient life on Earth, why not Mars?
If Perseverance’s sophisticated yet portable instruments are unable to definitively reveal any “biosignatures” of ancient organisms in Jezero’s rocks, it’s still possible that more powerful instruments in laboratories back on Earth could. To this possibility, Perseverance will store promising soil and rock samples in sealed metal tubes and leave them along its trail. A future mission to collect these samples and return them to Earth, the Mars Sample Return mission, is already being planned.
Seven Minutes of Terror
Landing an SUV-sized robotic rover on Mars isn’t a job for the faint of heart. The sequence of critical maneuvers from atmospheric entry and descent to landing must be pulled off without a hitch, and thus has been coined the “Seven Minutes of Terror.”
It takes about seven minutes from when the spacecraft hits Mars’ upper atmosphere to when it lands on the surface, and every step of the process is carried out automatically through carefully preprogrammed commands and actions. Radio signals between Perseverance and its controllers at the Jet Propulsion Laboratory in Pasadena took over 11 minutes to travel through space, so a real-time remote-controlled landing by human hand was impossible.
Once the landing sequence began, controllers back on Earth could only sit back and hope for the best until it was all over. Jezero Crater’s rough terrain added to the stress, making this landing the most dangerous yet.
Unlike the four previous Mars rovers, Perseverance didn’t go to the red planet alone. Hitching a ride on the rover’s underbelly is the tiny, 4-pound “Mars Helicopter,” named Ingenuity through the same student essay contest that gave us Perseverance.
The light-weight, double-rotor vehicle is a technology demonstration for aerial exploration of Mars in the future. Equipped with computer, navigation sensors, two small cameras, solar cells and wireless communication, Ingenuity will make one or more short flights sometime within the first month of the mission, after mission scientists and engineers find a suitable launch location and determine the most favorable weather conditions.
Life on Mars?
It’s exciting to think that we may be on the verge of finally uncovering hard evidence for the existence of extraterrestrial life. This will be a world-changing discovery, even if all we find is the chemical residue of single-celled microbes that lived a billion years ago. In whatever form the evidence comes, it will answer that age old question: Are we alone in the universe?
Imagine if Perseverance’s first high-resolution pictures of a Martian rock bore images of a fossilized life form of some sort?
Unlikely — but not impossible.
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