As a mere earthling, I bear in mind watching in fascination as
Sojourner despatched again photographs of the Martian floor throughout the summer time of 1997. I used to be not alone. The servers at NASA’s Jet Propulsion Lab slowed to a crawl after they acquired greater than 47 million hits (a document quantity!) from folks trying to obtain these early photos of the Pink Planet. To be truthful, it was the late Nineties, the Web was nonetheless younger, and most of the people had been utilizing dial-up modems. By the tip of the 83-day mission, Sojourner had despatched again 550 photographs and carried out greater than 15 chemical analyses of Martian rocks and soil.
Sojourner, in fact, stays on Mars. Pictured right here is Marie Curie, its twin. Functionally similar, both one of many rovers might have made the voyage to Mars, however considered one of them was certain to grow to be the well-known face of the mission, whereas the opposite was destined to be left behind in obscurity. Did I write this piece as a result of I really feel a little bit dangerous for Marie Curie? Perhaps. Nevertheless it additionally gave me an opportunity to revisit this pioneering Mars mission, which established that robots might successfully discover the floor of planets and captivate the general public creativeness.
Sojourner’s sojourn on Mars
On 4 July 1997, the
Mars Pathfinder parachuted by way of the Martian environment and bounced about 15 instances on glorified airbags earlier than lastly coming to a relaxation. The lander, renamed the Carl Sagan Memorial Station, carried valuable cargo stowed inside. The subsequent day, after the airbags retracted, the solar-powered Sojourner eased its manner down the ramp, the primary human-made automobile to roll round on the floor of one other planet. (It wasn’t the primary extraterrestrial physique, although. The Soviet Lunokhod rovers performed two profitable missions on the moon in 1970 and 1973. The Soviets had additionally landed a rover on Mars again in 1971, however communication was misplaced earlier than the PROP-M ever deployed.)
This large sandbox at JPL supplied Marie Curie with an approximation of Martian terrain. Mike Nelson/AFP/Getty Pictures
The six-wheeled, 10.6-kilogram, microwave-oven-size
Sojourner was outfitted with three low-resolution cameras (two on the entrance for black-and-white photos and a colour digicam on the rear), a laser hazard–avoidance system, an alpha-proton X-ray spectrometer, experiments for testing wheel abrasion and materials adherence, and several other accelerometers. The robotic additionally demonstrated the worth of the six-wheeled “rocker-bogie” suspension system that grew to become NASA’s go-to design for all later Mars rovers. Sojourner by no means roamed greater than about 12 meters from the lander because of the restricted vary of its radio.
Pathfinder had landed in Ares Vallis, an assumed historical floodplain chosen due to the big variety of rocks current. Scientists hoped to substantiate the previous existence of water on the floor of Mars. Sojourner did uncover rounded pebbles that prompt operating water, and later missions confirmed it.
A spotlight of Sojourner’s 83-day mission on Mars was its encounter with a rock nicknamed Barnacle Invoice [to the rover’s left]. JPL/NASA
As its first act of exploration,
Sojourner rolled ahead 36 centimeters and encountered a rock, dubbed Barnacle Invoice attributable to its tough floor. The roverspent about 10 hours analyzing the rock, utilizing its spectrometer to find out the fundamental composition. Over the subsequent few weeks, whereas the lander collected atmospheric data and took photographs, the rover studied rocks intimately and examined the Martian soil.
Marie Curie’s sojourn…in a JPL sandbox
In the meantime again on Earth, engineers at JPL used
Marie Curie to imitate Sojourner’s actions in a Mars-like setting. In the course of the authentic design and testing of the rovers, the workforce had arrange large sandboxes, every holding 1000’s of kilograms of playground sand, within the House Flight Operations Facility at JPL. They exhaustively practiced the distant operation of Sojourner, together with an 11-minute delay in communications between Mars and Earth. (The precise delay can range from 7 to twenty minutes.) Even after Sojourner landed, Marie Curie continued to assist them strategize.
Initially, Sojourner was remotely operated from Earth, which was tough given the prolonged communication delay. Mike Nelson/AFP/Getty Pictures
Throughout its first few days on Mars,
Sojourner was maneuvered by an Earth-based operator carrying 3D goggles and utilizing a cool enter gadget referred to as a Spaceball 2003. Pictures pieced collectively from each the lander and the rover guided the operator. It was like a really, very gradual online game—the rover typically moved only some centimeters a day. NASA then turned on Sojourner’s hazard-avoidance system, which allowed the rover some autonomy to discover its world. A human would counsel a path for that day’s exploration, after which the rover needed to autonomously keep away from any obstacles in its manner, comparable to a giant rock, a cliff, or a steep slope.
JPL designed
Sojourner to function for every week. However the little rover that would saved chugging alongside for 83 Martian days earlier than NASA lastly misplaced contact, on 7 October 1997. The lander had conked out on 27 September. In all, the mission collected 1.2 gigabytes of information (which on the time was a lot) and despatched again 10,000 photos of the planet’s floor.
NASA held on to
Marie Curie with the hopes of sending it on one other mission to Mars. For some time, it was slated to be a part of the Mars 2001 set of missions, however that didn’t occur. In 2015, JPL transferred the rover to the Smithsonian’s National Air and Space Museum.
When NASA Embraced Quicker, Higher, Cheaper
The
Pathfinder mission was the second in NASA administrator Daniel S. Goldin’s Discovery Program, which embodied his “sooner, higher, cheaper” philosophy of constructing NASA extra nimble and environment friendly. (The primary Discovery mission was to the asteroid Eros.) Within the monetary local weather of the early Nineties, the area company couldn’t threat a billion-dollar loss if a serious mission failed. Goldin opted for smaller initiatives; the Pathfinder mission’s total funds, together with flight and operations, was capped at US $300 million.
In his 2014 ebook
Curiosity: An Inside Look at the Mars Rover Mission and the People Who Made It Happen (Prometheus), science author Rod Pyle interviews Rob Manning, chief engineer for the Pathfinder mission and subsequent Mars rovers. Manning recalled that probably the greatest issues in regards to the mission was its comparatively minimal necessities. The workforce was answerable for touchdown on Mars, delivering the rover, and transmitting photos—technically difficult, to make sure, however past that the workforce had no constraints.
Sojourner was succeeded by the rovers Spirit, Alternative, and Curiosity. Proven listed here are 4 mission spares, together with Marie Curie [foreground]. JPL-Caltech/NASA
The actual mission was to show to Congress and the American public that NASA might do groundbreaking work extra effectively. Behind the scenes, there was a little bit little bit of accounting magic taking place, with the “sooner, higher, cheaper” missions usually being silently underwritten by bigger, older initiatives. For instance, the radioisotope heater models that saved Sojourner’s electronics heat sufficient to function had been leftover spares from the Galileo mission to Jupiter, so that they had been “free.”
Not solely was the
Pathfinder mission profitable however it captured the hearts of People and reinvigorated an curiosity in exploring Mars. Within the course of, it set the muse for the long run missions that allowed the rovers Spirit, Opportunity, and Curiosity (which, extremely, remains to be working practically 13 years after it landed) to discover much more of the Pink Planet.
How the rovers Sojourner and Marie Curie acquired their names
To call its first Mars rovers, NASA launched a scholar contest in March 1994, with the precise steering of selecting a “heroine.” Entry essays had been judged on their high quality and creativity, the appropriateness of the identify for a rover, and the coed’s data of the girl to be honored in addition to the mission’s objectives. College students from everywhere in the world entered.
Twelve-year-old Valerie Ambroise of Bridgeport, Conn., gained for her essay on
Sojourner Truth, whereas 18-year-old Deepti Rohatgi of Rockville, Md., got here in second for hers on Marie Curie. Fact was a Black girl born into slavery on the finish of the 18th century. She escaped together with her toddler daughter and two years later gained freedom for her son by way of authorized motion. She grew to become a vocal advocate for civil rights, girls’s rights, and alcohol temperance. Curiewas a Polish-French physicist and chemist well-known for her research of radioactivity, a time period she coined. She was the primary girl to win a Nobel Prize, in addition to the primary individual to win a second Nobel.
NASA subsequently acknowledged a number of different girls with named buildings. One of many final girls to be so honored was
Nancy Grace Roman, the area company’s first chief of astronomy. In Might 2020, NASA introduced it might identify the Huge Subject Infrared Survey Telescope after Roman; the area telescope is about to launch as early as October 2026, though the Trump administration has repeatedly stated it desires to cancel the project.
Nowadays, NASA tries to keep away from naming its main initiatives after folks. It quietly modified
its naming policy in December 2022 after allegations got here to mild that James Webb, for whom the James Webb Space Telescope is called, had fired LGBTQ+ workers at NASA and, earlier than that, the State Division. A NASA investigation couldn’t substantiate the allegations, and so the telescope retained Webb’s identify. However the bar is now a lot greater for NASA initiatives to memorialize anybody, deserving or in any other case. (The company did permit the hopping lunar robotic IM-2 Micro Nova Hopper, constructed by Intuitive Machines, to be named for computer-software pioneer Grace Hopper.)
And so
Marie Curie and Sojourner will stay a part of a rarefied clique. Sojourner, inducted into the Robot Hall of Fame in 2003, will all the time be the superstar of the pair. And Marie Curie will all the time stay on the sidelines. However give it some thought this fashion: Marie Curie is now on exhibit at one of the vital standard museums on the earth, the place thousands and thousands of holiday makers can see the rover up shut. That’s not too shabby a legacy both.
A part of a continuing series historic artifacts that embrace the boundless potential of know-how.
An abridged model of this text seems within the June 2025 print subject.
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