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Science Fiction Round 47: Asteroid Stories

Earlier this year, I got a recommendation to read Joan Vinge’s Heaven Chronicles, since it had been given a review as “the best asteroid story ever written”.  I haven’t read every asteroid-themed science fiction story ever written, and what is “best” is not well-defined.  But the stories were a pretty good read.

I’ll be focusing on the setting and world-building, rather than the detailed plot, but some spoilers do show up in the following.

Cover of the "Heaven Chronicles" Paperback.

This scene does appear in the book.  Kind of.  The attacking ships in the actual story are chemical rockets that were never designed to be flown in atmosphere (i.e. no wings or streamlining), and they use missiles rather than whatever makes those beams.  At least the gas giant Discus looks more or less right.

Heaven

The events of the two stories in the Heaven Chronicles book, “Legacy” and “The Outcasts of Heaven Belt”, take place in a many-centuries-distant future, in a planetary system around a star that has been named Heaven.  Although there is a fair bit of backstory to “Outcasts” takes place at another planetary system called Morningside, there isn’t any detailed discussion of what motivated humans to colonize space or of what has happened in the solar system – mentions of Earth are limited to characters reading books from “the Old World”.

Human settlement in the Heaven system focused on an asteroid belt around the star – the Heaven Belt.  This makes sense given the setup of the system: Two inner terrestrial planets, one of which is too hot to live on and one of which is only somewhat more habitable than Mars (there is just enough oxygen from local biology that you wouldn’t suffocate in the first couple of hours).  If you’re in the business of traveling across interstellar space, a resource-rich asteroid belt is perhaps more attractive than not-very-enjoyable planets.  Further out from Heaven, humans also settle the moons of Discus; a large gas giant; and asteroids in Discus’ leading and trailing Trojan Points.  With all of these resources, in conveniently-shallow gravity wells, the Heaven Belt became extremely populous and technologically adept – and it was well-known for being so among the various other human colonies.

Then, for reasons not thoroughly explained in the book, there was a war around Heaven.  Rocks were run into one another; habitats were blown to vacuum; and the resulting destruction of hardware and interruption of supply chains caused nearly-total collapse of civilization around Heaven.  All of the action of the book takes place more than a century After The End, when there are three main factions of survivors:

  • Lansing – formerly the capital of the entire Heaven Belt.  Kept a population going only because it had large enough parks and gardens under transparent shells.  No longer has infrastructure or technical skill to provide reliable radiation shielding, and the rock is starting to run short of water…
  • The Demarchy – a loosely-governed direct democracy, spread across one of Discus’ Trojan points, which retains the most technical skill (e.g. reliable nuclear-electric-propulsion).
  • The Grand Harmony – a totalitarian state covering Discus’s rings and moons.  Only has chemical rockets, which it supplies by mining ice from the moons.

The three factions are fighting with one another; for salvage from the Belt, for what technological hardware the Demarchy is able to manufacture, for ice and refined fuel and water and air from the Grand Harmony.  Then the starship Ranger arrives from Morningside, with orders to trade with the wealthy Heaven Belt.

Plot ensues.

A Couple of Cool Bits of The Setting

1. These stories respect orbital mechanics.  The large distances between the Trojan clouds and Discus, and the large and variable distances between both and the different rock piles of the Belt are key aspects of the plot.  Vinge worked out the relative travel times assuming constant-thrust rockets and minimal orbital motion while the ships are en route, which isn’t perfect, but it’s good to have a story that recognizes how big and constantly-shifting planetary systems are.  And it’s also nice that the lightspeed limit is carefully respected, both for communications and for Ranger traveling several lightyears.

2. In post-war Heaven, there are very few non-human animals.  Life-support is expensive, and it is hard to maintain a stable population of more than one species.  We see people pay extremely large sums for a pet chameleon and a tank of goldfish; and the crew of Ranger briefly poses as a party from Lansing that has traveled to the Demarchy to trade a cat for years’ worth of water and fuel.  Correspondingly, food around Heaven is vegetarian – lots of sealed containers of pasta, tofu, and soymilk on Demarchy ships.  We don’t see the fish breeder or the vitamin-supplement bacterial vats, but I’m willing to allow Vinge to hide those in corners.

3. Advocacy of gender equality.  The societies of the factions at Heaven are pretty horrifically sexist, and this is portrayed as the bad thing that it is.  And Captain Betha Torgussen of the Ranger is well-motivated and complex character who has no patience for sexist nonsense.

A Couple of Holes In The Worldbuilding

1. Dry Trojan Asteroids.  A lot of the conflicts between the different factions at Heaven are based around the Demarchy having a near-monopoly on nuclear technology (Lansing has a few nuclear-electric ships, which leak unhealthy amounts of radiation), while the icy moons of Discus give the Grand Harmony a near-monopoly on water and other volatiles.  The problem with this?  In the solar system, the larger objects in both the outer asteroid belt and the Jupiter Trojans contain a great deal of water.

It may be possible to have icy moons around a gas giant and for that gas giant to have non-icy Trojan clouds with some pattern of planetary migration in the early history of a planetary system, with the icy small bodies originally in the system getting scattered out.  I would have to do a bunch of detailed dynamical simulations to say.  So I’m not sure what I should think of Vinge’s choice here.

2. Morningside.  This place, seen only in the backstory for the Ranger’s crew, is a tidally-locked habitable planet around a red dwarf star.  Planets in the nominal habitable zones of low-mass stars are indeed expected to become tidally locked.  What isn’t clear is if such planets will be habitable – even in the ring right on the starward side of the terminator, where the Morningsiders live.  I can’t really fault Vinge on this one, given that she was writing circa. 1980 and scientists are still arguing about it now.

3. Interstellar Radio.  The crew of Ranger had originally planned to go to a third stellar system, to help a struggling colony there.  When they got a radio call over lightyears that things were doing better there, they changed their plan and launched from Morningside towards Heaven – planning to trade with the wealthy Heaven Belt for useful high-tech gear and come back to Morningside.

See the problem?  Morningside has communication with several different human colonies, as it should, and obviously knows about human presence in the Heaven system.  But they haven’t had any recent communication from Heaven – since well before the war, and the distances are such that signals sent from Heaven long after the war would have reached Morningside before the ship left.  Perhaps it makes sense that interstellar communications would not have been maintained during the collapse at Heaven.  But the fact of Heaven’s having dropped off of the interstellar radio network means that the Morningsiders should know that something very bad may have happened at Heaven, and should not necessarily expect a peaceful and wealthy culture to be waiting for them.

I don’t think this last bit makes the stories Vinge wanted to tell unsalvageable.  But the Ranger‘s crew should have been a bit more cautious and a bit less taken by surprise when The Grand Harmony started attacking them.