It looks like the TV room in Willy Wonka and the Chocolate Factory—a pristine chamber where folks in white jumpsuits and masks scurry about a collection of technological wizardry.
But instead of a camera that turns bratty kids into miniatures, the centerpiece is NASA’s new Mars 2020 rover, which the agency aims to deploy to the Red Planet this summer. Although less physics-defying than Wonkavision, it’s still every bit as magical, for one big reason: This is the mission that may finally answer whether life once existed on Mars.
In the final days of 2019, Jet Propulsion Laboratory, the Pasadena, California-based facility managing the mission, offered journalists rare access to High Bay 1, the cavernous live-streamed clean room where engineers have been building the Mars 2020 rover along with the descent and cruise systems that will guide its seven-month journey to Mars. The room’s strictly controlled temperature, humidity, and operating procedures minimize airborne dust, particulates, and biological contamination that could interfere with electronics and Martian experiments. It requires a meticulous regimen to access.
Before entering the room in small groups, we don “bunny suits”—fashion-challenged white polyester jumpsuits, booties, and hoods, along with surgical masks and latex gloves taped to the sleeve openings—before proceeding though an airlock where strong blasts of air remove additional microscopic debris. No makeup, perfumes, wool, clothing with ragged edges, or cloth camera straps are allowed, and technicians swab cameras and cellphones with alcohol before entry. JPL staff are further restricted to odorless shampoos, one type of deodorant, and no showers before entering. Even the clean room mascot, the ever-fabulous High Bay Bob, a mannequin modeling bright green Christmas-themed sunglasses, sports a bunny suit.
Keeping the Mars 2020 rover clean has ranked as the mission’s most unique challenge. Because of its astrobiology focus, JPL has taken more extreme decontamination measures than for predecessors Sojourner, Spirit, Opportunity, and Curiosity.
“We don’t want to get to Mars and find out in the sample that comes back, ‘Hey, it’s got my hair in it,’ ” says David Gruel, the Mars 2020 assembly, test, and launch operations manager. “All the rules of what you can’t do or bring on the floor are to safeguard the science of this mission.”
Beyond the building blocks of life
Mars 2020—which JPL began preparing in 2011, a year before Curiosity landed to great fanfare—is the first Mars probe to look for evidence of past microbial life. It will drill for, analyze, and collect samples of rocks and soil from areas once thought to have been habitable, and set them aside in sealed sterile tube caches for a future mission to return them to Earth in 2026 for more detailed study. The mission is the first step toward an objective JPL began discussing in the 1980s that eventually became the Mars Sample Return campaign.
“The rovers over the last few missions have tried to understand whether Mars was a habitable environment and has the building blocks of life,” says JPL director Michael Watkins. “And we’ve convinced ourselves that it did.”
Once those samples are run through Earth’s more sophisticated laboratories, they will offer an answer to some pressing questions: “Could life have formed there, did life form there, and if not, why not?” Watkins says.
The $2.5 billion project will also test technologies that address challenges facing the longer-term goal of human exploration. They include instruments that improve landing, produce oxygen from the planet’s carbon dioxide-rich atmosphere, identify geology and subsurface water, and chart weather patterns, dust, and other environmental conditions. There’s even a small solar-powered helicopter designed to fly in Mars’s reduced gravity and atmosphere.
NASA will designate an official name for Mars 2020 this spring, chosen from more than 9 million public submissions. The rover launches from Cape Canaveral in Florida during a July/August window for a planned February 8, 2021 landing on Mars’s Jezero Crater, an ancient lake bed with high potential for once harboring life. The mission will run at least one Mars year (about 687 Earth days) and cover up to 12 miles.
While particulate contamination is one daunting challenge, safeguarding highly sensitive electronics is another. Back inside the clean room, retractable belt barriers keep reporters at a modest distance from the mechanics to prevent accidental electrostatic discharges (ESD).
“The human body is made up of so much water, it has the ability to conduct electricity,” says James Sean Howard, the Mars 2020 assembly and test launch operations hardware quality assurance lead. “A shock from walking across a carpet and touching a doorknob is about 20,000 volts. You can damage some of these high-speed electronics with only five volts. So we mitigate that risk through electrostatic discharge control.”
Could life have formed there, did life form there, and if not, why not?”
This is accomplished by surrounding the hardware with air ionizers, which neutralize static electricity by pumping positively and negatively charged ions into the air. The clean room also maintains humidity levels above 30%, making the air more conductive, so it can absorb and distribute excess charges. When engineers work on the mechanics, they connect extendable wrist straps to a “ground,” a wire that returns electricity to the earth to prevent sparks. The bunny suits also contain grid patterns of tiny carbon-filled conductive filaments to discharge static fields from clothing. Upon completion, Faraday cages and ESD needles—metal spikes on the rover exterior that mitigate those pesky electrostatic charges—will protect its electronics on Mars.
Another significant barrier is the sheer complexity of the instruments and moving parts, many of which unfold from the rover after landing. The vehicle uses over 30 actuators, or systems that control moving parts. “Each of these mechanisms, gearboxes, and motors have hundreds of little pieces, all of which have to be designed, analyzed, assembled, and tested,” says Mars 2020 deputy project manager Matt Wallace. “They’re hard to make super reliable. And, of course, there’s no opportunity to fix them on Mars.”
Keeping contaminates from the cache assembly system, which places and seals the soil specimens in tubes, was especially tricky and crucial, considering its complexity and contact with samples. “The front third of the rover has a Swiss watch-like mechanism that takes the sample from the robotic arm, evaluates it, and hermetically seals it in the sample tube and encasement to lay on the surface of Mars,” says Zach Ousnamer, the Mars 2020 assembly, test, and launch operations rover vehicle integration and test engineer. “It required a second set of sterile gloves to touch specific hardware.”
Once on Mars, “we accept some aspect of cross-contamination” between drill sites, adds Jessica Samuels, the Mars 2020 lead flight system systems engineer. “But the most important thing we’re concerned about is not bringing any Earth contaminants.”
Advancing the technology behind Curiosity
The Mars 2020 rover leverages much of Curiosity’s configuration and landing system while advancing its science. The new rover is slightly larger than Curiosity, at 10 feet long (not including a 9-foot foldable robotic arm), 9 feet wide, 7 feet tall, and 2,314 pounds, and similarly powered with combinations of nuclear, battery, and solar energy. Its six aluminum wheels boast a more robust design and coating to avoid the dents, holes, and broken treads that have plagued Curiosity. This time around, its treads are sadly absent the letters “JPL” spelled out in Morse code, a cheeky use of wheel markings to visually measure distance rumored to have ruffled some feathers at NASA for promoting JPL.
Mars 2020’s Entry, Descent, and Landing system will replicate Curiosity’s nail-biting plunge, famously articulated in its “7 Minutes of Terror” video. The rover will journey to Mars inside a protective aeroshell comprising a top shell and bottom heat shield. A circular descent stage holding eight retro-rockets will then attach to the rover like a jet backpack that will eventually lower it to the ground. Minutes before touchdown, a parachute atop the upper shell will slow the craft’s descent until the heat shield is no longer needed and pops off. At that point, the descent stage will detach from the top shell, firing the retro-rockets toward the surface to slow its descent, before gently lowering the rover by tether to the surface. The descent stage then will detach from the rover, fly off, and crash elsewhere.
This time, a handful of new onboard technologies will enable more controlled descent maneuvering, precise landing, and data collection for future missions. The craft will also include a suite of cameras and mics for first-person views and sounds of the landing. Data sensors will measure the temperatures of the upper shell and bottom heat shield. One navigation system will guide descent by timing parachute deployment with the spacecraft’s position relative to the landing target. A second will assist landing by noting hazardous terrain during descent, comparing fresh images of the approaching surface with a preloaded map of the Martian surface.
Once on the surface, the rover’s work begins
Once on the surface, seven instruments—culled from 58 proposals worldwide and including contributions from French, Spanish, and Norwegian teams—will conduct geological assessments of the rover’s location to search for signs of ancient Martian life and pave the way for eventual human exploration.
While Curiosity scouted for and confirmed that Mars had the right environmental conditions to support microscopic life forms, Mars 2020 will look for proof in the form of biosignatures—chemical and molecular fossils that provide scientific confirmation of past life. Jezero Crater was the site of a lake and river delta more than 3.5 billion years ago, and rocks that formed in water may preserve evidence of the chemical building blocks of life.
“We’re looking for trace levels of chemicals, parts per billion, just very faint signatures . . . from billions of years ago on Mars,” Wallace says.
The rover carries a drill for coring samples and instruments to analyze and preserve samples in 43 test tube-size containers that it will leave on the Martian surface for later retrieval. That requires a separate mission because the landing system can’t deliver both a rover and ascent vehicle to lift the samples off Mars.
Instruments searching for life include advanced camera systems capable of panoramic and stereoscopic imaging and mineral analysis, radar for subsurface exploration, and spectrometers to determine mineralogy and organic compounds. Unlike Curiosity, Mars 2020 cameras will shoot color to enable imaging spectroscopy that can determine chemical compositions of samples.
Scientists are not looking for fragments of microorganisms so much as a collection of residual chemical fingerprints. A spectrometer called SHERLOC—short for Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals—will shine a 100-micron ultraviolet laser on a surface to get the spectral signatures of its components. This can help determine the mineral makeup, organic molecule type, and chemistry, such as the existence of nitrates or chlorates. “All of that added together will tell a chemical story, that there’s a really good chance there’s a biosignature there and we should bring this sample back,” says SHERLOC principal investigator Luther Beegle.
Mars 2020 will aim to assist future robotic and human missions by testing how certain technologies fare in a Martian environment. An onboard surface weather station will measure temperature, pressure, and dust size and shape to better understand Mars’s atmospheric density and winds. It will also demonstrate oxygen production from Martian atmospheric carbon dioxide, which human missions will need for breathing and rocket fuel. And it will attempt 90-second test flights and aerial photography with a small helicopter tethered to the rover’s belly. If successful, it will be the first aircraft to fly on another planet.
While the technologies inching us closer to human exploration are impressive, it’s even more thrilling to think that we’re on the cusp of a decades-long goal.
“We’re hoping to answer the fundamental question of whether life could have evolved someplace other than Earth,” says Wallace. “We’ve gotten to the doorstep on that question, and it’s time to walk through the door.”