Mars Trilogy: The Voyage Out

Part of the Mars Trilogy Technical Commentary Series. Contains spoilers for this chapter and earlier chapters. Google Mars .kml. Literary commentary podcast.

After the chaos of Festival Night, the narrative travels back 27 years to December 2026, when the First Hundred depart for Mars, and follows Maya. From here, the narrative remains in chronological order, excepting flashbacks, for the rest of the series. While each part is told from the perspective of one of the main characters, each part opens with a shorter section in italics from a different perspective, providing background and exposition.

This chapter occurs almost entirely as the First Hundred travel from Earth to Mars, taking nine months. There is a lot of technical detail here describing how their spaceship works, how their crew works, and how their cultural shard develops. As always, there are a few technical goofs but the broad brushstrokes are scientifically accurate and describe a plausible, if bloated, Mars exploration architecture.

In our first meeting, KSR and I talked a bit about technical inaccuracies. He expressed that he strongly preferred to get it right because he knew much of his readership was more technical than he is, and he knew that inaccuracies would throw the reader out of the story. In the world’s least intentional flex, he pointed out that many interested readers had written in a list of errata that were corrected after the 18th reprint. On this note, it behooves us all to be humble – I have yet to write a blog that survives a careful read from a clever reader and I am indebted to their attention to detail, as are all the other readers. We must also remember that KSR’s characters have flown to Mars, and have forgotten more about Mars travel than all of us living humans today combined have managed to learn to this point. We’re really at the “banging rocks together” age of space travel.

The First Hundred travel to Mars in a large spaceship called, as is mandated by the International Mars Fiction Authority, the Ares. Which is Greek for Mars. Throughout the chapter, we get snippets of physical description of the Ares, which allows me to describe here how it works.

The Ares is large, by real world standards, composed of dozens of Shuttle main tanks and similar pieces of Russian/Soviet rockets. This is because when the Mars Trilogy was written, the Russian space program was still a pinnacle of human achievement. History has not been kind to its legacy. As I write, a Soyuz docked to the ISS has sprung a coolant leak, potentially crippling it and its capability to transport crew back to the Earth. This is just the latest in a long string of agonizingly embarrassing failures brought about by unchecked kleptocracy in post-Soviet Russia.

It’s worth also noting that the Ares is gargantuan by the standards of the current default Mars transportation reference design – the Starship. While Starship itself is a lot larger than Shuttle, Starship was designed as a self-contained Earth-Mars (and Mars-Earth) transportation system. It draws from a different set of architectural questions that, instead of supposing that some finite investment of time and effort would eventually render in-space construction of giant space stations relatively cheap, proposes to avoid in space construction all together. Twenty years of cis-Lunar space stations and Shuttle tank salvage? Delete!

Starship could be adapted to provide artificial gravity but being able to land on Mars imposes steep size constraints. Starship is about the same size as a Shuttle external tank, and its usable internal volume for crew is about half that again, at 1000 m^3. This is substantially larger than the cabin volume of the A380 or the International Space Station, though! Whereas the Ares has to be large to accommodate 100 people and their civilization, each Starship would focus on rapid transit with numerous independent cargo launches and relatively small crews. Overall, Starship can deliver much more mass to Mars for far lower cost, even if Shuttle cost something like its original projections. It cannot be denied that Starship is not quite as compelling a canvas for literary exploration, as a fleet of sharply pragmatic cargo landers has a singularity of purpose unmatched by the relatively ponderous and openly romantic Ares.

Artist’s conception of the Ares approaching Mars. Art by Don Dixon.

Artificial gravity is obtained on the Ares by spinning the entire structure at 4 rpm, providing a centrifugal force equivalent to Mars’ surface gravity of 0.38 g. Using the equation a = v^2/r, we can derive an effective radius of 21 m, which is about half the radius a hex ring composed of Shuttle tanks would be. Roughly 3 rpm would be sufficient. In KSR’s universe, Shuttle tanks have also been used to build two space stations, an L5 station, a lunar orbiting station, a vehicle for the first crewed mission to Mars (which John Boone flew on), and lots of uncrewed freighters in support of the First Hundred’s mission. This process is supported by standard floor plans, coupling units, propulsion packs, and other neat stuff that is, happily, very easy to do in text!

In the first chapter, KSR elided potential controversy to do with radiation exposure with Frank’s observation that they take 15 rem per year. In this chapter, we’re told NASA has conducted many years of testing on human health in reduced gravity, and that the health effects are minimal, even though the crew still exercises for three hours per day. Exercise also has positive effects on mental resiliency. Sadly, in our year 2022 we still have zero data on human, or even mammal, health at 0.38 g for extended periods, except for a single JAXA mouse experiment in a small centrifuge. Fortunately it seems likely that the impact of lower g will be less severe on health than other ambient hazards for humans traveling to Mars.

The Ares embodies a very romantic vision of space exploration. Almost fully automated luxury space communism. It has many hallways, a Russian dining hall in Torus D, and a US dining hall in Torus B. There is, for the 1990s, sophisticated indoor lighting to simulate sunrise, and the dining hall has potted trees, vines, and five different species of song birds. There’s a bubble dome at the end of the 500 m long central axis where people can float around and watch the stars. It has more than 500 rooms in total, like a large hotel.

The biosphere team runs a farm in tori C, E, and F. Torus E has a swimming pool, sauna, and whirlpool bath. I’m not quite sure what a whirlpool bath is, perhaps something invented at the Esalen Institute? There is also a forest biome, with pine, aspen, and birch trees, as well as seven separate rooms with parks. Despite the general hassle of having to assemble the Ares in space over two years, it appears the designers did not feel volume-constrained. It also seems likely that KSR was reflecting on the Biosphere 2 experiment, which also had many biomes intended to be representative of certain Earth environments.

One potentially awkward aspect of a hex ring rotating for artificial gravity is that the floor would appear to slope a lot towards the corners – to the point of needing stairs. The book mentions 45 degree angles between segments, which is appropriate for an 8 tank ring, so perhaps at some point KSR reduced the size of the ring but forgot to change the interstitial angle to 60 degrees, or 30 degrees at each end of the coupler unit.

The Ares, assembled in Earth orbit, fires its transfer stage just once, for 9 minutes, to escape Earth and fly to Mars on a fairly standard Hohmann low energy orbit. LEO to Trans-Mars Injection (TMI) requires between 3.8 and 4.2 km/s, and while the 2027 launch window is pretty good, the lowest delta-v launch requires just seven months to get to Mars, while nine months intersects with a tricky inclination mismatch. Nine months is, of course, required to fully gestate a human and their culture for the next phase of history.

The TMI burn is described as taking nine minutes and generating noticeable force. 3.8 km/s over 540 seconds is about 7 m/s^2, or about 0.7 gs. Of course, exploiting the Oberth effect to achieve TMI does not require a rapid impulse, and many injection burns in modern systems take much longer, with a much smaller, lower thrust engine. For example, truck-sized Galileo’s burn to capture into Jupiter’s orbit used an engine about the size of a football which burned for almost an hour.

A Hohmann transfer brings the Ares close to Mars with just a little bit of excess speed, perhaps 900 m/s, but Mars’ gravity accelerates the ship downwards, such than an unbraked impact would occur at 900 m/s + escape velocity, which is an additional 5030 m/s, for a total of at least 6 km/s, or 21,600 km/h. This is somewhat smaller than the 40,000 km/h and 120 km/s impact velocities given at various points describing failed simulation runs, but still easily enough to create a smoking crater.

Mars orbital insertion (MOI) and later, entry, descent and landing (EDL) is non-trivial at the best of times, let alone in a gigantic interplanetary spaceship composed of hundreds of modules bolted together. KSR gives a strong account of this process, which embodies the crescendo of their space flight ennui and struggle to be reborn on a new world.

With one week to go, Mars is the size of the Moon. They are approaching at about 1 km/s, which implies they are about 600,000 km away, at which distance Mars, with a diameter of 6779 km, would subtend 0.01 radians, or 0.5 degrees – the same as the Moon. Nice! From the Earth, the sun also subtends about 0.5 degrees in the sky, but on Mars that is closer to 0.3 degrees – substantially smaller.

To brake into orbit, the Ares employs a gigantic deployable modular heat shield, allowing the otherwise unshielded spacecraft to dip into the atmosphere within 30 km of the surface, burning off excess speed without having to use additional propellant. The braking process is described as pulling 2.5 gs – a lot of force on an otherwise unladen structure – and subjecting the occupants to torques and bumps as they’re strapped into their chairs on the bridge. It is unclear why the ship has a bridge, but it does. The ship vibrations imply the structure is relatively undamped and stiff. After eight minutes, they’ve skidded around a quarter of the planet and braked into a 35,000 km elliptical orbit with a period of roughly one day. This is roughly right as far as orbital parameters go. 2.5 gs for eight minutes produces more than 11 km/s of delta-v however, while braking into a 24 hour Mars orbit requires only a tenth of that. Still, 48 seconds of 2.5 gs would be quite enough!

During the capture sequence, KSR makes a rather obscure reference to the Ares traversing regimes of molecular, transitional, and continuum hypersonic flow. Because most of the Ares is a giant tower of stuff hiding behind a heat shield, it is critically important that the shield form a detached shock, otherwise hot Mars atmospheric molecules will plough in behind the shield and heat things up too much.

After capturing into orbit, the shields are taken down and stored – it unclear why they are not either left in position or jettisoned, but the entire craft is reconfigured to prepare for landing. 20 landing craft, stored parallel to the axis, take passengers down to the surface in groups of five. The rest of the ship is to be parked near Mars’ inner moon Phobos to be used as an emergency return vehicle. It is not clear how the First Hundred is to ascent from Mars, nor how the Ares would be restocked for this flight.

Mars EDL is a difficult and mysterious process, all the more so when Red Mars was published. So it was not a surprise for me to read in the closing paragraphs of the chapter that Maya, Sax, Vlad, Nadia, and Ann strap in, push the button, and watch the sky turn incandescent pink as they fall onto their new planet, without pages and pages of precise numerical data. If you’re so inclined, I have a basic 2D Mars EDL calculator.

At the symbolic half way point of the voyage, the Ares encounters a solar flare, which in deep space can easily deliver enough radiation to an unshielded person to cause acute radiation sickness and death. The narrative describes flying in 2027 to coincide with the low point in the 11 year solar cycle, though Cycle 25 will actually peak in 2025. This event gives the author an excuse to throw in some action, so the crew get to do all kinds of hatch-battening to prepare. We also encounter the flare shelter, located in the core of the central axis, surrounded by tanks filled with water and with a thick shielding floor that rotates to keep the humans on the other side of the sun.

While water is a very effective shield, so much so that just 15 cm or so is adequate to catch most of the damage, a heavy metal shield that’s not very thick will generate a lot of secondary particles with higher Q factor than unshielded particles. Worse, the energetic solar particles gyrate around the Sun’s magnetic field lines with an effective radius of around 1000 km, such that a simple eclipsing shield, even if oriented along the solar magnetic field rather than pointed at the sun, would not shield most of the radiation, which will appear to fill half the sky.

Still, having invisible, intangible radiation pinging up through the floor creates a compelling image. Maya wants to clench her knees together, John attempts to dodge the particles, Arkady plays some Beethoven, some people crowd around a screen displaying radiation counts, while others cower at the other end of the module and try not to experience space sickness. John remarks that during his earlier flight they had about one dentist lead jacket between them, and he took 1600 mS on the mission – equivalent to five years on the ISS. After the storm, the farm animals are considered too radioactive to eat (despite surviving the storm in their own less comprehensive shelter) while the dining hall songbirds died, representing perhaps the limit of the reach of Earth’s good intentions. The total dose was 60 mS inside the shelter, and 1400 mS outside – a fatal dose. 60 mS is equivalent to roughly four CT scans, though seems rather a lot for the magnitude of their radiation shelter.

So much for the Ares. Let’s now commentate on the other technical half of this chapter – the people!

An emerging undercurrent for the series is the people story – how to tell a future history story with characters both believable and relatable, even with just 100 to represent the entirety of humanity.

In this chapter we learn that the crew went through an interminable selection process, including a year-long analog in Antarctica – also the title of another of KSR’s works, which also touches on the alienation of the quiet, big, cold continent. Antarctica also serves as legal analog, since the Outer Space Treaty owes much to the Antarctic Treaty.

Michel, the French psychiatrist, exists here as the embodiment of the selection process, and a rather hapless character eventually selected, at the last minute, to fly along to Mars. In the opening prolog to this chapter, he laments that the selection requirements push the limits of the discipline of psychiatric analysis.

So they went on being brilliant and accomplished enough to stand out, but normal enough to get along. They were old enough to have learned a great deal, but young enough to endure the physical rigors of the work. They were driven enough to excel, but relaxed enough to socialize. And they were crazy enough to want to leave Earth forever, but sane enough to disguise this fundamental madness, in fact defend it as pure rationality, scientific curiosity or something of the sort—which seemed to be the only acceptable reason for wanting to go, and so naturally they claimed to be the most scientifically curious people in history! But of course there had to be more to it than that. They had to be alienated somehow, alienated and solitary enough not to care about leaving everyone they had known behind forever—and yet still connected and social enough to get along with all their new acquaintances in Wright Valley, with every member of the tiny village that the colony would become. Oh, the double binds were endless! They were to be both extraordinary and extra ordinary, at one and the same time. An impossible task, and yet a task that was an obstacle to their heart’s greatest desire; making it the very stuff of anxiety, fear, resentment, rage.

We get some insight into the makeup of the crew, with a grab bag of prior professions, including astronaut, medical, computers, systems, architecture, geology, biosphere design, genetic engineering, biology, electrical/mechanical engineering, and construction. Almost all with track records of exceptionally high performance and personalities to match. The average age is 46, with the youngest 33, and oldest 58. English, Russian are the dominant languages among others, while 8 members of the crew are linguistic orphans, with no other native speakers. Frank speaks five languages, all badly! There were fifty men and fifty women: thirty-five Americans, thirty-five Russians, and thirty miscellaneous international affiliates, fifteen invited by each of the two big partners. In 2022, the program run 50-50 between Russia and the US looks odd, but remember Red Mars was written during perestroika! KSR needed a culturally opposing pole to build the story around.

We see this chapter from the perspective of Maya, a seasoned Russian cosmonaut through whom we learn more about the personal side of her space exploration, including several affairs over the course of the voyage to Mars and recollections of earlier escapades in space stations. This is notable particularly because the text remarks on NASA’s prudishness then and even in 2022, NASA is still incredibly conservative in their discussion of this topic.

Maya is co-mayor of the village. Here, we get a glimpse into management structure, with Frank leading the American contingent. Maya remarks that it is difficult to manage the Russians, having no mandate. The Australian Antarctic Division, at least at one point, selected seasonal base leaders by whoever came second in a popular vote, specifically to avoid a compelling mandate.

We meet more of the crew, introduced to help embody ideas and factions that motivate the plot.

Ann Clayborne and Saxifrage Russell are introduced as opposing poles of a dispute over alteration of the alien Martian surface, their respective positions underscored by their extremely cryptic names. Both of them are written as somewhat neuro-atypical, as are Phyllis and Hiroko, while Maya, Nadia, John, and Frank present as NT.

Janet Blyleven initially acts as a reporter, filming dispatches for Earth media with “video glasses” until, tired of being shunned by the increasingly introverted Ninety-Nine, resigns the role of media interfacing and open collaboration with old Earth powers to Phyllis and her faction. Phyllis, who is set up as an antagonist outside of the scientific circles, also leads the Christian contingent of around a dozen. John and Phyllis’ argument about the nature of god anticipates the young earth creationism stuff that went on during the presidency of George W. Bush, but which had burned out (for now) at the tail end of “Internet Atheism”.

A couple of other factions manifest, including the medical crew led by Vlad and Ursula, and the farm crew led by Hiroko, whose talent and otherness is underlined in the text by emphasizing her young age (33), her rejection of the concept of money, her unique ability to jump down the length of the axis, and her acolytes shrinking from the artificiality of their surroundings by sleeping in the dirt of the farm between the rows of plants. Maya also suspects the farm crew are hiding a stowaway, which she glimpses through a container of algae before questioning her own sanity. Hiroko is rumored to be planning to have children by all the men on Ares, which is definitely a power move.

While Hiroko’s faction is cloaked from Maya’s perspective, Arkady’s is not. Arkady is the most vividly drawn caricature, with flaming red hair and beard pierced by two wild electric blue eyes. Arkady is bent on redesigning human society from the ground up on Mars, rejecting old Earth authority, property rights, architectural plans, and science’s traditionally apolitical stance. Arkady sees work as life and art, not just wages. Arkady recognizes the inherent contradiction of sending 21st century scientists using 19th century social systems and 17th century ideologies to Mars, where their interaction with the environment will force bidirectional adaptation and change.

However, his advocacy for domes as an embodiment of a purely egalitarian society cause me to question his technical judgement. They have about 20% better volume-to-surface area ratio, which is sometimes important for heat transfer, at the cost of roughly 100x increase in technical complexity. There is a reason domes are uncommon structures! KSR leaves the outsider Phyllis to point out that communism showed that utopia is not possible. At least for some values of utopia and possible.

During the solar storm sequence, Arkady begins preaching to the First Hundred and Sax wonders how someone so heterodox ever passed the selection board. Arkady mocks Michel and the very concept of the “Revised Minnesota Multiphasic Personality Inventory,” stating that he simply gave the exact opposite to every question, while Sax claims to be the only candidate who answered every question truthfully! Frank points out that the selection committee increased the stability of the group by using the “Harvard Solution,” id est, admitting a few betas. He is able to see this because he knows that’s how he was admitted to Harvard.

Arkady and John form an alternate power center to Maya and Frank’s officially bestowed leadership, and both advocate for their own form of idealized society that may not work very well in practice, though at least John’s concept, embodying the best of American liberalism, is syncretic enough to interface constructively with other systems.

In contrast, Arkady cements the purity of his vision by volunteering his faction for the hardship assignment no-one else wants, taking Ares to Phobos and building a space station on the small Martian moon, which is apparently something NASA wants to do in addition to landing on the surface. The remainder of the crew descends to land at the site chosen for Underhill.

The chapter ends with the crew incompletely united and Frank speculating aloud “Why are we going?