As a mere earthling, I bear in mind watching in fascination as
Sojourner despatched again images of the Martian floor throughout the summer season of 1997. I used to be not alone. The servers at NASA’s Jet Propulsion Lab slowed to a crawl once they obtained greater than 47 million hits (a file quantity!) from folks trying to obtain these early photos of the Crimson 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 images 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 an identical, both one of many rovers may have made the voyage to Mars, however one in every of them was sure to change into 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 slightly unhealthy for Marie Curie? Possibly. Nevertheless it additionally gave me an opportunity to revisit this pioneering Mars mission, which established that robots may 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 the Martian environment and bounced about 15 occasions on glorified airbags earlier than lastly coming to a relaxation. The lander, renamed the Carl Sagan Memorial Station, carried treasured cargo stowed inside. The subsequent day, after the airbags retracted, the solar-powered Sojourner eased its manner down the ramp, the primary human-made car to roll round on the floor of one other planet. (It wasn’t the primary extraterrestrial physique, although. The Soviet Lunokhod rovers carried out 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 big sandbox at JPL supplied Marie Curie with an approximation of Martian terrain. Mike Nelson/AFP/Getty Photos
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 coloration 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 turned 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 historic floodplain chosen due to the big variety of rocks current. Scientists hoped to verify the previous existence of water on the floor of Mars. Sojourner did uncover rounded pebbles that recommended 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 on account of its tough floor. The roverspent about 10 hours analyzing the rock, utilizing its spectrometer to find out the basic composition. Over the following few weeks, whereas the lander collected atmospheric data and took images, 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. Throughout the unique design and testing of the rovers, the workforce had arrange big sandboxes, every holding 1000’s of kilograms of playground sand, within the Area 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 Photos
Throughout its first few days on Mars,
Sojourner was maneuvered by an Earth-based operator sporting 3D goggles and utilizing a cool enter machine referred to as a Spaceball 2003. Photos 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 just a few 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 recommend a path for that day’s exploration, after which the rover needed to autonomously keep away from any obstacles in its manner, corresponding to a giant rock, a cliff, or a steep slope.
JPL designed
Sojourner to function for per week. However the little rover that might stored 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 Nationwide Air and Area 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 house company couldn’t danger a billion-dollar loss if a serious mission failed. Goldin opted for smaller tasks; the Pathfinder mission’s general price range, together with flight and operations, was capped at US $300 million.
In his 2014 guide
Curiosity: An Inside Take a look at the Mars Rover Mission and the Folks Who Made It Occur (Prometheus), science author Rod Pyle interviews Rob Manning, chief engineer for the Pathfinder mission and subsequent Mars rovers. Manning recalled that the most effective issues in regards to the mission was its comparatively minimal necessities. The workforce was liable for touchdown on Mars, delivering the rover, and transmitting photos—technically difficult, to make certain, however past that the workforce had no constraints.
Sojourner was succeeded by the rovers Spirit, Alternative, and Curiosity. Proven listed below are 4 mission spares, together with Marie Curie [foreground]. JPL-Caltech/NASA
The true mission was to show to Congress and the American public that NASA may do groundbreaking work extra effectively. Behind the scenes, there was slightly little bit of accounting magic occurring, with the “sooner, higher, cheaper” missions usually being silently underwritten by bigger, older tasks. For instance, the radioisotope heater items that stored 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 Individuals and reinvigorated an curiosity in exploring Mars. Within the course of, it set the muse for the longer term missions that allowed the rovers Spirit, Alternative, and Curiosity (which, extremely, remains to be working almost 13 years after it landed) to discover much more of the Crimson Planet.
How the rovers Sojourner and Marie Curie obtained their names
To call its first Mars rovers, NASA launched a pupil contest in March 1994, with the particular steering of selecting a “heroine.” Entry essays had been judged on their high quality and creativity, the appropriateness of the title for a rover, and the coed’s data of the girl to be honored in addition to the mission’s objectives. College students from all around the world entered.
Twelve-year-old Valerie Ambroise of Bridgeport, Conn., received for her essay on
Sojourner Fact, 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 along with her toddler daughter and two years later received freedom for her son by authorized motion. She turned 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 particular person to win a second Nobel.
NASA subsequently acknowledged a number of different girls with named constructions. One of many final girls to be so honored was
Nancy Grace Roman, the house company’s first chief of astronomy. In Could 2020, NASA introduced it might title the Vast Area Infrared Survey Telescope after Roman; the house telescope is ready to launch as early as October 2026, though the Trump administration has repeatedly stated it desires to cancel the challenge.
As of late, NASA tries to keep away from naming its main tasks after folks. It quietly modified
its naming coverage in December 2022 after allegations got here to mild that James Webb, for whom the James Webb Area Telescope is known as, had fired LGBTQ+ staff at NASA and, earlier than that, the State Division. A NASA investigation couldn’t substantiate the allegations, and so the telescope retained Webb’s title. However the bar is now a lot increased for NASA tasks to memorialize anybody, deserving or in any other case. (The company did enable 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 Robotic Corridor of Fame in 2003, will at all times be the superstar of the pair. And Marie Curie will at all times stay on the sidelines. However give it some thought this manner: Marie Curie is now on exhibit at one of the crucial common museums on the earth, the place tens of millions of holiday makers can see the rover up shut. That’s not too shabby a legacy both.
A part of a persevering with collection historic artifacts that embrace the boundless potential of know-how.
An abridged model of this text seems within the June 2025 print challenge.
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