Founded in 1958, the DSN is the Earth’s most sophisticated means of interplanetary exchange – the system by which NASA passes telemetry data between Earth and its spacecraft. Each 70m-diameter dish listens patiently, picking up radio signals from across and beyond the solar system. This in itself is a miracle. “[Only] a small fraction of [a spacecraft’s transmission will] actually hit the Earth and only one ten-billionth of that fraction [will] hit the actual receiver,” explains journalist Oliver Morton in his book Mapping Mars. Given the astonishing faintness of the signals, the capacity to receive any transmission from the void, writes Morton, “has been one of the least celebrated wonders of the space age[...] an abilityat least as wonderful as that of actually launching things into space”.
The DSN is NASA’s locus. Far away, the agency’s spacecraft roam the solar system, harvesting data from bodies whose distance renders them otherwise silent. Untouched, unseen, these astral bodies are captured and conveyed as radio waves, before being reconstructed back on Earth. They are, in Morton’s parlance, bodies “created by[...] instruments and mappings”; worlds “transformed by the imagination that runs over [them]”. It is only when a spacecraft’s data arrives on Earth that the places it has visited become fully real to us. Overseen by the Jet Propulsion Laboratory (JPL) in the foothills of the San Gabriel Mountains, California, the DSN is the means by which Morton’s one ten-billionth of a fraction becomes one ten-billionth of a world, and whereby missives coded into a radio signal are reformed to provide scientific imagery and instrument readings.
Since 2004, however, the JPL has transformed a portion of the data it receives into a new form of constructed world. “Postcards,” writes Jim Bell, a geophysicist at the JPL and Arizona State University who led the initiative. “That word sounds a little small to me[...] but that is what we called them when we shot them and as they came back from Mars, and I can’t call them anything else now.”
Over the past 16 years, Mars has hosted three different sources of postcards. Two are now dead, the third is still mailing. If all goes to plan, a fourth correspondent will be in place come 18 February 2021.
In the context of Mars, postcard is meant quite literally. The Martian postcards are panoramas of the planet’s landscape – 360° images documenting their senders’ location. These are harsh locations. Bathed in an atmosphere of around 95 per cent carbon dioxide, and experiencing temperatures that range between 20°C and -153°C, the Martian surface is prone to gigantism. There is Olympic Mons, a shield volcano two and a half times taller than Mount Everest; the Hellas Planitia, an impact crater 7,152m deep and 2,300km across; 1 and Valles Marineris, a canyon some 4,000km long, 200km wide and 10km deep. “The mountains of Mars are the size of American states, its grandest canyons continental,” explains Morton. “Plains the size of Canada lie flooded by undivided sheets of lava.”
Nevertheless, from the ground, the planet seems somehow formless, its features lost amidst their own enormity. The surface of Mars is not consistent – it is variably smooth, hummocky, cracked, dune-like or mottled – but it is relentless. “Even stripped of people, with their cities and their borders and their histories, a map of earth would not be this unyielding,” says Morton. “Global truths and discrete units of geography would draw the eye. River catchments would tile the plains, mountain ranges would stand like the backbones of continents. There would be seas and islands, well defined. But Mars is not like that. It is continuous, seamless and sealess.” Roger Wiens, a planetary scientist who has worked at the JPL, frames this same point in terms of loneliness. “The beautiful but deserted terrain of Mars evokes the feeling of an abandoned mansion,” writes Wiens in his 2013 book Red Rover. “It seems that everything is there except the occupants. The same sun rises and sets.[...] The wind blows the sand grains ever so slightly from day to day. But no one is there.”
The Martian postcards begin to impose some sense of perspective and agency on this infinitude. They are photographic coordinates – a Wish-you- were-here to the folks back home – stitched together from thousands of images and then rendered to erase the seams. Most importantly, they are shot from ground-level, as opposed to the satellite imagery we are accustomed to from orbiters. “[They’re] the closest representations yet made of what it must be like to be there, standing on Mars,” Bell writes in his 2006 book Postcards from Mars, a document of his time at the JPL. Each postcard, Bell explains, is “a combination of science, past experience, and some artistic license”.
In creating a postcard, numerous design decisions are made. “It [takes] thousands of additional images to produce [a] single view,” explains Janet Vertesi, a Princeton sociologist who has spent years studying NASA’s spacecraft teams as an ethnographer. “[There are] not only the individual frames that make up the panorama, but a digital trail of images that [are] displayed, annotated, dissected, planned, disputed, and ultimately agreed on.” Decisions are taken to standardise colouration across the component photographs 2 and to determine the point at which to “cut” the panorama to produce a two-dimensional image, as well as how to crop the composite image to frame the vista it shows. “The relation to reality that all art must bear is a particularly strange one for this project,” Bell notes. “It is not abstract art, but it also isn’t a reality that any human has quite witnessed yet, either.” The images that form a Martian postcard may not be shot by people, 3 but nor are they captured by just any kind of spacecraft. Critical to the concept of the postcard is the nature of the correspondent.
For the majority of the Space Age, Mars’s surface has been known either through the satellite imagery provided by orbiters like Mariner 9 (1971-72), whose top-down vistas began the work of mapping the planet (revealing, in the words of Mariner geologist Michael Carr, “a wonderland[...] unfolded before us”), or else through on-planet lander photography. The first lander images date from 20 July 1971, when NASA’s Viking 1 reached the Chryse Planitia, a smooth plain in Mars’s northern equatorial region. “When the signal came that Viking had landed safely at 5:12 a.m. (PDT),” says political scientist W. Henry Lambright in his 2014 book Why Mars: NASA and the Politics of Space Exploration, “everyone at JPL gave a loud cheer, followed by hugs, laughs and other expressions of sheer relief”. The relief was merited – Viking 1 was NASA’s first spacecraft and only the world’s second, to successfully soft land on another planet. 4 For the first time, the faintest signal of Mars’s surface, seen from the ground, began to reach the DSN.
A static observer, Viking 1 set to work photographing panoramas of red rock and rubble beneath salmon-pink skies. 5 A second lander, Viking 2, began its work from Mars’s Utopia Planitia in 1976. “Mars is really talking to us and telling us something,” enthused Harold P. Klein, the chief biologist for the missions, praising the Vikings as they probed the landscape, carving out knowledge of Mars’s history, geology and chemical makeup. The images provided by these landers were so vital that NASA’s Pathfinder team, when threatened in 1994 with budget cuts that imperilled their mission’s camera, penned a protest letter. “Try to imagine two successful Viking landings on Mars in 1976 followed by no images[...],” the team wrote. “Try to imagine the successful landing of Apollo 11 on the Moon with only voice communication – no pictures, no samples, and no televised ‘first step.’ It is important to recognise that images from the surface of Mars will prove success to the American public (and Congress) and provide them with tangible results they can comprehend.” But the Vikings weren’t sending postcards. At least not in Bell’s sense of the term.
In his 1980 book Cosmos, the astronomer Carl Sagan set out the limitations of the Vikings. “I found myself unconsciously urging the spacecraft at least to stand on its tiptoes, as if this laboratory designed for immobility, were perversely refusing to manage even a little hop,” he explained. “How we longed to poke that dune with the sample arm, look for life beneath that rock, see if that distant ridge was a crater rampart.[...] For all the tantalising and provocative character of the Viking results, I knew a hundred places on Mars which are far more interesting than our landing sites.”
In part, Sagan’s frustrations are the friction inevitable in designing any spacecraft – the interrelation between scientists and engineers. “Usually, astronomers and scientists want systems that are going to be much more capable than we can design,” says Manan Arya, an engineer at the JPL. “It’s a process of negotiation of telling them what is achievable within realistic costs and schedules, and then meeting them halfway.” Missions are launched for the benefit of the science resulting from them, but their operation is dependent on engineering strategies. Adding to the complexity of this interrelation is the fact that engineers’ experience of the spaces they are designing for is almost entirely mediated by the knowledge generated by scientists. “It’s a lot of talking to people and experts,” confirms Arya. “You’re constantly learning new physics [for the] environment you have to design for, and intense amounts of modelling goes on. Part of it is building an intuition for what an environment is like, and there is also an intuition that develops slowly over time about things that are going to work and things that are not going to work. At this point, for instance, I know not to put dissimilar metals together because they’ll expand at different rates and temperatures.” All spacecraft are limited, then, but not necessarily through any paucity of the design process; given the spaces they have to navigate and the complexity of the tasks they have to perform, it’s a wonder they operate at all.
Nevertheless, Sagan was broadly right in his lament: landers are a frustratingly limited form of exploration. As robotic emissaries for humankind, they open a window onto Mars, reframing an alien world in new, more human terms. In Morton’s words, they have helped transform Mars into “a world of science, untouchable but inspectable and oddly accessible, if only through the most complex of tools”. Thanks to the images sent back by the Vikings and their ilk, Mars has become “a world of places and views, a world that would graze your knees if you fell on it, a world with winds and sunsets and the palest of moonlight. Almost a world like ours, except for the emptiness.” But it is this same emptiness that highlights the limitations of a static lander. In any kind of exploration, movement is primary, not least in the context of a planet where no human has ever set foot. It is through movement within a space – the capacity to adopt different perspectives and to choose the way in which we frame an environment – that a location begins to become legible and take on attributes that might allow us to describe it as a “place”. This idea is rooted in the arguments set out by the geographer Edward Relph in his 1976 phenomenological study Place and Placelessness. “In our everyday lives places are not experienced as independent, clearly defined entities that can be described simply in terms of their location of appearance,” wrote Relph. “Rather [they] are sensed in a chiaroscuro of setting, landscape, ritual, routine, other people, personal experiences, care and concern for home.” Relph’s full chiaroscuro of experience is likely impossible to obtain through the robotic exploration of Mars, but even a partial version becomes difficult if we cannot imagine movement across the planet’s rocks. “A place is not a place[...] if all you can do is look at it,” writes Morton. “[For] a place to be a place, you must also be able to move around it, to go away and look back, to see it from more than one angle.” Without movement, what chance is there of Mars ever becoming a planet of places in Relph’s sense of the term?
Motion is particularly important to the idea of a postcard – a record of a journey undertaken deliberately and of places visited through freely determined movement. “The difference between the views of Mars from the Vikings [and the Martian postcards is the] difference between ‘acquiring images’ and ‘taking photographs’,” writes Bell. “Acquiring images is a technical, science-driven, resource-limited activity.” By contrast, the creation of a photograph requires the freedom to shape its frame that is betokened by movement. “I can think about the same kinds of issues that landscape photographers consider in their quest to capture the spirit and stories of the land,” writes Bell. “How can we frame this particular shot?[...] What is the balance of sky and ground? Do we visit the scene in natural light or with enhancing filters? And how do we interpret the view later, in the computer ‘darkroom’ where we process the images?” As Sagan noted in 1980, “The ideal tool is a roving vehicle carrying on advanced experiments, particularly in imaging, chemistry, and biology.” Only a rover is able to send postcards.
To date, Mars has welcomed four rovers of three different kinds. Each varies considerably from the others, but the principle is the same – “A little car [that can] drive out,” as physicist Geoffrey Briggs put it in 1990. The first of the Mars rovers, Sojourner, landed on 4 July 1997 as part of NASA’s Pathfinder mission and remains the vehicle that best fits Briggs’s bare-bones description. The 0.6m-long Sojourner was solar-powered, a tabletop buggy whose aesthetic was more remote-controlled car than advanced planetary vehicle. 6 Trundling around its landing site in Mars’s Ares Vallis, Sojourner was a tech demo that nevertheless carried out useful science – applying an alpha-particle X-ray spectrometer to the surfaces of rocks to determine their chemical composition – as well as serving as an important cultural touchstone.
“It was Sojourner, more than anything else, that turned the landing site in Ares Vallis into a place,” notes Morton, citing the images showing the rover’s slow progress and the treads it left in the ground. “Sojourner put activity into the images and brought change to the changeless surface. Her tracks in the dust brought time and motion to Mars. They made the landscape a place of purposeful activity, rather than just a site for disembodied study[...].” Driving a total of 0.1km, at a speed of 0.024km/h, Sojourner traversed the small rock garden that formed its range for a total of 83 sols or 85 days, 7 photographing its world in miniature. They were not yet postcards – Sojourner was unable to take panoramas – but the rover’s freedom of movement set a template for what was to come. As Louis Friedman, executive director of the Planetary Society, put it, Sojourner “reawakened the [Apollo-era] image of NASA as ‘the can do’ agency”, fed in large part by its website (the first “internet mission” of its kind), which supplied regularly updated news from the rover and its lander. “[No] event up to this time had as many ‘hits’ on the Internet – 80 million a day in the first days, 450 million by the beginning of August,” writes Lambright. “This decision to use the Internet brought about the largest virtual participation in exploration by people since the world watched the Apollo Moon landing in 1969.”
Sojourner was followed in 2004 by the twin Mars Exploration Rovers (MER), Spirit and Opportunity. The first of the fully fledged Martian correspondents, the MER rovers borrowed basic design principles from Sojourner – such as its rocker-bogie suspension which forewent springs in favour of six wheels whose joints could rotate and conform to the contours of Mars’s surface 8 – but otherwise tore up the copy book. As a NASA press release from the time had it, Spirit and Opportunity were to be fully fledged “robotic geologists”, each one able to “see sharper images,[...] explore farther and examine rocks better than anything that’s ever landed on Mars.” To help enable their mission, each rover would carry a Pancam: a pair of cameras positioned on a 1.5m mast to obtain high-resolution images of Mars in wavelengths from ultraviolet through to infrared. “Pancam,” Bell explains, “would be providing the only colour pictures from the rovers and would be the first moving set of (essentially) human eyes on the planet.” It is Pancam to which we owe the first postcards – our first record of something approaching free, uninhibited movement across the Martian landscape.
It is easy to animalise Spirit and Opportunity – they’re adorable. The two rovers were solar-powered like Sojourner, but instead of aping their forebear’s flat rectangle of photovoltaic cells, their solar panels were designed to wrap neatly behind their bodies like a swan’s wings. Meanwhile the Pancams have a WALL·E-esque charm, 9 as if each rover were peering quizzically at the world it found itself in. Spirit and Opportunity were engineered to travel a maximum of 100m per sol and remain operational for up to 90 sols. Part of the appeal of the MER rovers, however, is the seeming earnestness with which they set about their tasks, and the manner in which they wildly bucked expectations. Spirit remained active for 2,623 sols, covering a distance of 7.7km and faithfully reporting back to the DSN throughout, despite suffering a series of crippling engineering setbacks. “[About] seven hundred days into what was expected to be a ninety-day mission, the rover’s right front wheel jammed at an awkward angle, never to turn again,” writes Vertesi in her 2015 book Seeing Like a Rover. “[After that, the] engineers [had to] drive the robot backward, and gingerly at that, dragging its stuck wheel.” Spirit eventually fell silent after 751 days stuck in soft sand at a site named Troy. 10 “People literally went to grief counselling,” notes Kalind Carpenter, an engineer at the JPL whose work focuses on mobility systems. “It was so hard to keep that little guy alive and get it unstuck.”
Opportunity, meanwhile, was an even greater success. MER had been devised to find evidence of past water activity on Mars and, shortly after landing on the Meridiani Planum, Opportunity began returning imagery showing hundreds of ball-bearing sized grains littering the ground. These grains were a form of mineral deposit that the MER team dubbed “blueberries”, and which were later determined to have been left over from the evaporation of a salty body of water. “Opportunity’s sort of the glamour girl,” Vertesi reports one of the MER operators explaining. “She went to Mars to find water, and she sort of fell into a hole and opened her eyes and there’s evidence of water.” That Opportunity remained operational for 5,352 sols (15 years), covering a distance of 45.16km and sending back postcards every step of the way, only added to the sense of triumph and endeavour surrounding the programme. “Within a few weeks of landing, we had found key evidence that there was once liquid water on Mars and that the environment must have been much more Earthlike at some point in the distant past,” notes Bell, who argues that this prestige was enhanced in the public consciousness by Opportunity’s postcards. “We have not been the first to see the surface of Mars, but we have had the privilege of being the first to see the places we have visited in an entirely different, and ultimately more human way.” When Opportunity finally fell silent on 10 June 2018, after reporting a low battery and approaching storm, 11 public grief was palpable. “Was I a good Mars Rover?” Opportunity asks the Grim Reaper in a widely shared meme. Wide-eyed and trusting, Opportunity is led across the Martian sands by Death. “No,” the Reaper responds. “I’m told you were the best.”
The best, perhaps, but not the most capable. On 6 August 2012, the Curiosity rover landed on Mars. In comparison to its predecessors, Curiosity is leviathan. “It was universally accepted within NASA and outside the agency that [Curiosity] was the most technologically challenging vehicle ever designed to move across the surface of another world in space,” notes ex-NASA scientist David Baker in his 2013 book NASA Mars Rover: Owner’s Workshop Manual. Certainly, Curiosity has little of the cuteness of its predecessors. Its purpose is clear in its robust titanium wheels and chunky frame, giving it the appearance of futuristic farm equipment – an interstellar combine data harvester.
Curiosity is the size of a small SUV, more than three times the weight of the MER rovers, and carries 10 times the weight of science equipment. Its rocker- bogie suspension gives it 0.6m of ground clearance for traversing rocks, while its mast (topped with Pancam’s successor Mastcam) stands 2.2m off the ground, with the rover’s capabilities bolstered by a robotic arm that can extend an additional 2.2m. To cap it off, Curiosity is not solar powered like its predecessors – and therefore hostage to Mars’s fluctuating seasons and weather patterns – but rather fuelled by an inbuilt radioisotope thermoelectric generator. The vehicle is so heavy that NASA was forced to abandon its method of landing rovers on Mars – cocooning them in airbags and letting them bounce to a rest – in favour of a new methodology dubbed “sky crane”, in which a rocket- powered descent vehicle lowers the rover on nylon tethers. Part of the Mars Science Laboratory (MSL) mission, Curiosity represents a fulfilment of the promise of the earlier rovers: an “observatory on wheels” as Lambright puts it, and an opportunity to explore Mars more fully. The creation of MSL, argued NASA’s former chief scientist James Garvin in an October 2008 letter to the editor of Science, meant that the JPL was “ready to assault the Martian frontier”.
The frontier metaphor has recurred throughout the Space Age, but seems particularly apposite in the case of Mars. “[When] the world thinks of Mars, the images it conjures up are, more often than not, images of the American West,” notes Morton, and it matters little that the physical resemblance between the two is slight 12 – the metaphor is chiefly ideological rather than aesthetic. 13 “Since the 1960s, America has ceaselessly talked about space as a new frontier, a continuation of the nineteenth century’s expansion – and one result of this rhetoric has been an eagerness to see the landscapes of the solar system in terms of the landscapes of the American West,” Morton argues, adding that the comparison expresses a “continuity between the pioneers of the space age and the pioneers of the West”. Rovers feed into this narrative readily, in part because of their aesthetic connections to the railways, the form of transport that defined the American West. “Rover tracks,” concludes Morton, provide a clear symbol of planetary exploration, “just as railway tracks defined the Columbia River landscapes of Carleton Watkins in the 1880s”.
Certainly, the Martian postcards are normally framed so as to position either a portion of the rover or its tracks prominently in view. The tracks are particularly evident – gouged deep and crimson into ground on which the rover has disturbed the blanketing layer of planetary dust. This imprint generates a sense of activity on an otherwise desolate planet, as well as imposing a veneer of human-generated order. “Locating viewers in a stark landscape with a scene laid out around them[...] recalls the picturesque convention in eighteenth-century landscape painting,” notes Vertesi, who understands the postcards as embodying a form of “Martian picturesque”, an aesthetic that transforms a rover’s activities into a human visual experience. “It arranges the landscape around an observer who is embedded within it at a particular location,” she notes. “Human presence on Mars thus appears natural and seamless, arising from the landscape.” Through postcards, an alien planet is rendered both familiar and, crucially, attainable. It is, Vertesi writes, a “practical image craft that draws Mars as the new American frontier.”
As it stands, this frontier is being pushed back daily. Since Curiosity landed on Mars, it has driven 20.4km; exceeded its designed lifespan of 668 sols by well over 2,000; found evidence of persistent liquid water in the planet’s past, and organic carbon in its present-day rocks; and supplied a steady stream of postcards that have documented its movements across the 154km-wide Gale crater. As John Grunsfeld, a former NASA chief scientist, puts it, “The action right now is on the surface, and that’s where we want to be.”
Bolstered by this ongoing success, the JPL is currently prepping a new correspondent for Mars: Perseverance. Scheduled to launch as part of the Mars 2020 mission between 17 July and 5 August, the rover is expected to land in Mars’s Jezero crater (thought to be the site of an ancient, dried-up lake system) in February 2021. Once on the planet, Perseverance will begin searching for signs of past microbial life on Mars, caching rock core samples within sealed tubes that may be recovered and returned to Earth by a future mission. The new rover will carry different scientific equipment to Curiosity, and has received a redesigned set of aluminium wheels to allow for steeper climbing, but is otherwise closely modelled on its predecessor. “We know how to control costs,” said Mike Griffin, NASA’s then-administrator, in 2008: “just build more of what you built the last time.”
While Curiosity cost around $2.5bn to develop and launch, 14 Perseverance is currently estimated to top out at $2.04bn. It is a significant saving, although given that NASA’s total federal budget for the 2020 financial year is $22.6bn, it is still a considerable investment. “[Perseverance] is meant to be build [to] print,” explains Carpenter of the JPL’s design for the new rover. “People have saved a lot of money through lessons learned and a lot of the designs from the last one.” Nevertheless, there have been changes to the blueprints, although NASA is not necessarily keen to communicate these in detail. “If you’re under contract to build the same thing and you go off-script – and if people aren’t necessarily aware of that – then they can get very touchy about what you’ve done on their dime,” 15 notes Carpenter. “But one thing I will say is that it is not the same rover. Its science goals are very different; the location is very different; and its instruments are completely different. [Perseverance] should be exciting to everyone.”
Some changes are obvious. The flashiest is the presence of the Mars Helicopter, a solar-powered drone that will be carried by Perseverance as a tech demonstration of powered flight in the Martian atmosphere. “For the helicopter, we’ve been waiting for the power density of motors, the power density of batteries, and the processing power [to become sufficient],” says Carpenter. “It suddenly hit a point about six years ago where we looked at those three parameters and realised that the technology is finally there. We can fly on another body.” Less glitzy, but probably more immediately meaningful, are the inclusion of two new pieces of equipment that may help expand the way in which we experience the Martian surface: microphones and a methane sensor. “One of the coolest things going on with 2020 is that it’s going to have ears – you’re going to be able to hear Mars and the sounds of the rover’s wheels as it’s driving around,” says Carpenter. “Another thing we’ve added is the methane sensor and it’s going to be interesting to see if we [can use that to] see the chemicals and the [atmospheric] makeup [of the planet]. You could easily have an installation where you could move around with the rover and hear and smell what it’s like to be on Mars.”
One of the smallest design gestures on Perseverance, however, feels particularly significant: the presence of a visible-light camera. It is the first time this technology has travelled to Mars and the photographs that emerge will be different to the postcards supplied by either the MER rovers or Curiosity. “One way to see Mars is by combining a set of filters through red, green and blue channels in an image-processing program,” explains Vertesi of the way in which both Pancam and Mastcam have functioned. These combined filters produce an approximate true colour (ATC) image, “an estimate of the actual colours you would see if you were there on Mars”. Vertesi advises caution with this vocabulary. True colour images, she warns, are no more “true” than those produced through other kinds of filters. “[ATC] is a technical term that refers to a particular combination of filters that approximates the range and type of light sensitivity exemplified by the human eye,” she notes. Even Bell, an advocate par excellence for the MER postcards, acknowledges that the colours seen by Pancam are “approximate” and, at best, “a good estimate of what humans[...] would see if they had been there.” With Perseverance, the imagery returned by the visible-light camera will finally move beyond this estimate. 16 “We normally never do this because we’re looking for the extended range to get as much data as we can, and then someone colorises it,” notes Carpenter of the decision to include the camera, which NASA describes as a “public engagement payload”. “But this time you’re going to be able to see as if you were standing on Mars, which to me is a no-brainer. As a child, I wanted to go; I wanted to walk around. As much as the scientist and engineer in me realises that [this camera is] not as important as other [instruments], there’s no reason not to give that to the world.”
This sense of connection between rovers and people is at the heart of the Martian story, particularly in terms of their operation by teams at the JPL. All of the NASA rovers have been autonomous to a degree, 17 but their movements are nevertheless carefully mapped and prescribed from the neighbouring planet. “The rovers do not conduct science or see by themselves,” explains Vertesi. “Each day they received detailed instructions from their human team on Earth about where to go and what to do.” It takes somewhere between 13 and 24 minutes for radio signals to pass between Mars and the DSN, rendering constant communication impractical. As such, rover teams connect with their robots once a sol, encompassing both “downlink” (receiving all data from the previous sol) and “uplink” (sending detailed commands to the rover for the upcoming sol). 18 “I take as a first-order assumption that the rovers cannot be understood without the complex network of people and software on Earth that animate them,” says Vertesi of this relationship, while acknowledging that many at the JPL would frame this sense of intimacy even more sharply. “We are the corpus, the body of this rover,” she describes one operator explaining. “We are making that thing do what it does on Mars.”
Visualisation is critical to this form of operation. Perseverance will carry nine engineering cameras, divided between hazcams, navcams and a cachecam. Of these, it is the former two that are relevant for movement. 19 Hazcams are located on the body of Perseverance and point downwards so as to detect obstacles to the front and back of the rover; navcams are mounted on the rover’s mast and provide stereo imagery to help plan a route. “[The] rover’s view of the world when driving is very much like your view of the world if you imagine yourself trying to make your way through a dark, cluttered room with nothing but a flashbulb,” one MER operator told Vertesi. “So you can kind of take a picture in the world, and you can get a sense of where there’s a safe path, and you walk a little way along that safe path and you pop the flashbulb again.” The rover follows paths and objectives set by its operations teams based on the imagery it provides; calculates the distance it has been asked to drive through measurements of its wheel rotation; and then proceeds slowly. “[Although] Rover team members joke about getting the ‘keys to the rover’,” notes Vertesi, “there is no joystick that controls real-time operations.”
To facilitate this shared responsibility for movement, rover operators practice a form of projection. “My body, by the way, is always the rover,” one engineer told Vertesi, before contorting herself into a variety of poses to demonstrate how each of her body parts might map to the structure of a rover – her chest becoming the robot’s front, her shoulders its solar panels, and its antennae erupting from her spine. “In order to be fully prepared for my job... I need to literally be that vehicle.” The critical point, of course, is that being a rover is not very much like being a person. Throughout a mission, rover teams attempt to see in a different way in order to take advantage of the fact that it is not them that is crossing the Martian landscape, but rather robots with alternative forms of perception, locomotion and communication. “[A rover operator] confessed to me,” notes Vertesi, “that while planning a drive, ‘I have frequently tried to put myself in the rover’s head and say, [‘What do I know about the world?[...] The rover has senses that we don’t have[...] It never really sees the world in colour but it can see parts of the spectrum that we can’t.’”
Rovers may be proxies for the human exploration of Mars, but they are not proxies for humans – their modes of being in and experiencing the world are radically different to our own. The majority of images returned from the Martian rovers, for instance, have not been easily identifiable postcards, but rather technical shots designed to help steer, or else vistas captured through filters and conducive to the overall scientific mission – what Bell might term “acquiring images” rather than “taking photographs”. These images show worlds in shades of violent blue, pink and yellow, with landscapes illuminated like folds of the aurora made solid, oozing with chemical signals that leach livid from the ground. These forms of imaging, Vertesi writes, are strange and take practice to read, but they are vital to the operation: “One scientist I interviewed who was looking for sulphate content on Mars explained, ‘If you get a particular [filter] combination the sulphates just jump out at you. It’s like they turn green or blue or something.’” Another rover scientist went further in arguing for the need to move beyond approximate true colour images: “Okay, we know Mars is red, we get it! Seeing more natural Mars colours isn’t helping, I’m not learning anything.” Rovers communicate visually, but they extend this medium to express the non-visual too. 20 They not only let us see worlds we cannot at present view directly, but facets of those worlds that we could never hope to see.
If Perseverance lands successfully in February 2021, it will not simply be an ambassador for humankind in an inhospitable environment. It is a technology to extend our natural capabilities – a planetary machine designed to transform the alien into the understandable. “[Rover operators] do not project themselves outward, into the body of the rover as human proxy,” says Vertesi. “Rather, they themselves adopt the rover’s bodily apparatus with its unique bodily sensitivities in order to understand and interact with Mars.” The postcards that the rovers send back, however, stand contrary to this. They locate viewers on the Martian surface, reversing Vertesi’s dynamic and representing an instance where the rover mimics the bodily apparatus and sensitivities of a human. “[The Martian picturesque] is not a view from nowhere or a God’s-eye view,” writes Vertesi. “Nor is it especially a rover’s eye view.” Which is why they resonate. The Martian postcards are a human’s view, a record of movement, belonging and presence sent from a world that will admit of none of these things. “I wanted them to be postcards,” writes Bell, “views showcasing the beauty of the natural environment that we now found ourselves in.” This is perhaps overstated: we are not there yet.
1 The energy released in the impact that created Hellas would, Morton notes, have been sufficient to “[boil] half the Earth’s oceans dry”.
2 The images are taken over the course of several hours, allowing for shifts in colour as atmospheric conditions change over time.
3 Or at least not directly; the connection between spacecraft and their operators is a knotty one.
4 The honour of being the first fell to the Soviet Union’s Mars 3 probe, which landed on 2 December 1971 but failed after 20 seconds – although it did transmit a partial panoramic image that shows no detail. To understand “soft land”, compare it to the hard landing of Mars 3’s predecessor – Mars 2 – which crashed into the planet’s surface on 27 November 1971. Attempts to contact Mars 2 were, unsurprisingly, unsuccessful.
5 A colouration that had to be later corrected. The Viking team ultimately determined the Viking lander site’s rocks to be “moderate yellowish brown” and its sky “light to moderate yellowish brown”. Less catchy, but the Red Planet is perhaps more accurately the Moderate Yellowish Brown Planet.
6 “Puny”, as Wiens puts it.
7 A Martian day is known as a sol, and lasts for a mean period of 24 hours 39 minutes 35.244 seconds.
8 A system that David Baker, an ex-NASA scientist and now editor of the British journal Spaceflight, rates so highly that he dismisses “Earth-based off-road vehicles and SUVs” as having “failed their owners in not seizing this logical form of mobility”.
9 Pixar researched WALL·E by visiting the JPL, where the MER rovers were designed and built.
10 “[The] rovers were finite resources and[…] their short lives could be over at any time,” writes Vertesi. “This was colloquially referred to as ‘the sniper’: as in the expression ‘the sniper could strike at any time.’”
11 This went viral when a rather poetic translation of Opportunity’s final data transmission duped people into thinking that the rover had literally transmitted the words: “My battery is low and it’s getting dark.”
12 Although, as Morton notes, it is not absent altogether: “the planet undoubtedly looks more like Arizona than it does Arkansas or the Ardennes[...] Mars may not be very similar to the American West – but it is similar enough to give the metaphor substance.”
13 It is blatantly nationalistic, with more than a smattering of colonial connotations also.
14 “I [like] to explain that Curiosity cost the price of a movie ticket for every person in the United States,” says Wiens of this cost. “The public would get its money’s worth.”
15 This is hardly surprising – space travel of any form has always been intensely political. “Large technical achievement, especially when dealing with government and costing billions over many years,” explains Lambright, “does not happen automatically.”
16 This is not necessarily Vertesi’s point, however. The human eye is itself a kind of filter and it is worth thinking about why we ascribe more verisimilitude to the wavelengths it detects than the extended range perceived by a rover.
17 Each rover has been successively more autonomous than the last. Perseverance, NASA promises, has “greater independence than Curiosity ever had[…] [allowing it] to cover more ground without consulting controllers on Earth so frequently.”
18 This, of course, brings challenges in terms of scheduling.“Rovers don’t care about nights or weekends on Earth,” notes Bell. “They don’t care about holidays, or your kids’ birthdays, or your anniversary. They don’t care if your son had to have an emergency appendectomy, or that you had to deal with weeks spent away from your family every month. All they care about is waking up, getting their commands, measuring, photographing, and radioing the results back to Earth, and then going back to sleep. Relentlessly. Like robots!”
19 Cachecam will be used in the storage of rock core samples.
20 Non-visual to a human viewer, anyway.