Sialhaith

Extreme Sport

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1

2016_E(Alternate words: Espresso, Effect, Ecumenopolis, Eldritch, Evidence, and Ending. Added to the list.)

The shuttle hangs barely a hundred yards away to my retrograde, cargo airlock still agape; the pilot’s nerves must surely be worn to shreds with the delay in this atmosphere-scraping orbit, even more than mine.

Time for another check-out. I punch for another round of diagnostics on suit, shield, and thrusters, reciting the mnemonics. Suit integrity, blue. Cerametal oversuit integrity, blue. Oxygen, blue. Regenerator-scrubber, blue. Liquid cooling systems, blue. Heat sink, blue. Communications circuits, blue. Cold-gas thrusters, blue on diagnostics, blue on pressure. Drogue chute, blue. Main chute, blue. Shield integrity and strain, blue…

I resist the urge to unlock the foot couples and do another visual inspection of the shield. I’ve already checked it over the regulation thrice and once more for good fortune. I bounce some terahertz rays off it instead, and no weak spots show up. Any more than they did last time.

Count breaths. Nice and regular. I have this, dammit. Twelve simulations, no fatalities. I’m prepared. I glance up and down at the copper foil loosely wrapped over my suit. If I’m not, at least I’ll make a spectacular green fireball…

A voice breaks in. “Meteor One, this is Sialhaith Orbital. Acknowledge.”

“Sialhaith Orbital, Meteor One. Go.”

“Meteor One, net-zeps are in position and your window begins now. Commence entry at your discretion. Window closes in four point six minutes. Over.”

“Orbital, Meteor One. Commencing entry now. Clear.”

This is it. My navigation HUD lights up with trajectory plots, burn times, entry ptojections. I trigger the cold-gas thrusters with a thought and nitrogen hisses, shoving at my back as I drop lower in orbit. The shuttle’s ACS flickers overhead and lemon-yellow Sialhaith wheels below me as I reorient, getting the shield in position to feel the first touch of air and swift, sudden, roaring plasma shock.

Time to kiss the sky.

 

Lumenna-Súnáris System (4): Sialhaith

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I/3. Sialhaith

Class: Sialhain
Orbit (period): 0.58 au (161.3 T-days)
Orbit (ecc.): 0.02
Radius: 3,680 miles
Mass: 4.3 x 1024 kg
Density: 4.96 g/cm3
Surface gravity: 0.84 g

Axial tilt: 7.9°
Rotation period:  23.1 T-hours

Black-body temperature: 347 K
Surface temperature (avg.): 1,015 K

Atmosphere: Extremely dense, furnace-hot, primarily CO2.
Atmospheric pressure (sfc.): 117.6 atm
Hydrographic coverage: 21%

Satellites: None.

Sialhaith may not actually be one of the less pleasant hells, but if you wanted to build one, it would undoubtedly be where you’d go real-estate shopping.

It’s a “wet greenhouse”, consisting of furnace-heat over eroded rocky deserts, moistened by small oceans of boiling acid, with an atmosphere primarily of carbon dioxide and water vapor, mercifully concealed from space by its impenetrable belts of caustic, lemon-yellow, sulphuric-acid smog clouds. (They wrapped probes in platinum hulls just to find that much out.) If it is not the single least hospitable place in the entire System, the Sialhaith Extreme Tourism Advocacy Branch would like to know.

Naturally, in the future, people tried to ecopoese it. It didn’t stick: in the end, the residents of the aerostats – it’s very easy to build cities that are naturally buoyant in the Sialhain atmosphere – that were intended to monitor the ecopoesis process ended up buying out the project, having decided that they liked their lifestyle and its uniqueness just the way it was.

There’s very little on the surface itself but some minor scientific and resource-gathering outposts, and small-scale dome-warrens belonging to the sort of person who demands that their lifestyle be the absolutely most challenging available.

Oh, and Fort Inferno, because Legionary drill instructors also demand a lifestyle that’s the absolutely most challenging available.

 

Zeppelin

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ZWhile they are used on many colonies, due to the extremely small investment in infrastructure required, Sialhaith (Lumenna III) is the world on which the modern airship has reached its apotheosis. In Sialhaith’s hot, thick atmosphere – the planetary ecopoesis program was bought out and effectively terminated in its 150th year by the aerostat consortium – a standard oxygen-breather atmosphere serves as a potent lifting gas, the factor which enabled its sky cities to exist in the first place.

This same factor makes Sialhain an airship designer’s dream.

Picture, if you will, a broad, flattened ellipsoid envelope of tough, lightweight, clear aerogel – perhaps a full mile in length. It supports a traditional gondola, certainly, holding its reactors, ducted magnetoaerodynamic engines, and pylons for shuttle aeronefs hanging below, but unlike conventional designs, the gondola doesn’t represent the habitable space of the airship. The lifting gas, after all, is entirely breathable. Instead, look down upon the envelope, and in place of ballonets, ballast pumps, and other support machinery within, see instead a single, vast, open volume, in which the designer has scattered a small town’s buildings over a lightly wooded park. That’s the simplest possible Sialhain airship.

How many Sialhain designers do you think were content to build the simplest possible airship?

No Place Like It

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Tinf?  It’s a thermal hell of a planet.  It’s sheathed in thick clouds of helium and methane and sulfur dioxide, scattering rain that’ll etch metal.  Actinic Kortinf whips the atmosphere, thick as it is, into hurricane frenzy during the day, making ions enough to thrash the ground with lightning bolts of a size you’d never see on one of your milk-mild garden worlds.  The leaden oceans melt shortly after dawn and are boiling by afternoon.

Then at night the temperature crashes again, and the flash-floods come with dusk.  Aurorae light the sky all night, walls and curtains of color, green and yellow and blue and red as the atmosphere discharges again – Kortinf puts out too many rads that reach the ground during the day, so we can only come up to clean off the lava and tend the arrays at night.

And continuous radio noise, so you chaps with the wireless interfaces couldn’t hear yourselves think – nothing but hash all the time, from the lightning by day and the aurorae by night.

Leave?  Chaos, no!  It’s just like home!

– Alyáné Janaris-ith-Janaris, Sialhaith-adapt technician