Talasea's Lessons: Uphill and Downhill

This article was written by navigator Tali Talasea. All temperatures given in degrees Celsius.

It is often said that geometry drives cannot be used deep in a planetary or stellar gravity well, but the "why" is rarely touched upon. Allow me to cast some light on it.

In reality, it is not impossible to use a geometry drive in a gravity well. As long as both the disintegration and reintegration points are outside of the atmosphere, technically the drive should be able to work. However, the immense majority of modern drives will spit out errors, generally either a generic code 001 "translation failed due to wrong parameters" or a more specific 0011 "translation failed due to projected compensation outside of acceptable range."

So what does it all mean? See, while the geometry drive remains a paracausal device, conservation of energy still applies to it. When a ship translates "uphill" or "downhill" a gravity well, its potential energy is affected. Moving "uphill" means an increase in potential energy, while moving "downhill" means a decrease. Because conservation of energy applies, this difference has to go somewhere. The modification in potential energy is given by the following formula:

DU = -(m*g*DH) where DU is the change in energy in Joules, m the mass of the translated ship, g the acceleration due to gravity and DH the change in altitude related to the surface of the object considered.

Another formula allows to convert this difference into heat. If a ship was to drop from geostationary orbit to a low planetary orbit in a single translation, it would accumulate enough heat to melt on the spot -- and the crew would be killed instantly. If on the contrary a ship was to do the opposite journey, its temperature would drop to several minus thousand degrees, also killing the crew. However, the ship might survive...or would it? Remember, the absolute zero is at -273 degrees and counting, so the residual energy would have to go elsewhere. "Elsewhere" means the drive, which would shatter and become unusable.

This is why flight computers, by default, forbid "uphill" and "downhill" translations in deep gravity wells. The setting can be deactivated, but I strongly recommend to keep it on. Note that, unlike the built-in matter reintegration safety, it only relies on pre-established knowledge of the environment: thus, it is possible to drop deep inside a gravity well during a blind jump. This is part of the reason why explorers always translate right outside an unknown system for their first contact.

Of course, you'll notice that even in deep space, you're always under the gravitational influence of a multitude of objects, but their effect is negligible and thus will not create significant temperature changes. Dropping a bit too close to a planet (we call this "shaving") might heat the ship up slightly, but nothing dangerous.

Two additional notes for the keenest students:

-- Yes, it is technically possible to create an infinite energy machine by having a ship translate uphill with exactly the right parameters, but they are so constrained that said machine will be extremely, extremely pitiful.

-- And yes, it is also possible to cool down a cargo by translating "uphill" for just the right amount of energy difference (let's say -20°C). This is a relatively widespread if a bit unconventional method for flash-freezing sensitive cargo.

I thank Winchell Chung of the Atomic Rockets website for the formula.

Talasea was illustrated by ElenaFeArt as a commission for Starmoth.

Laser Grids

Laser grids are nigh-ubiquitous spaceship equipment that have been in use since the early days of the interplanetary era. Much like most personal laser equipment such as the stylus, they are first and foremost utilitarian tools that also double as weapons.

Civilian laser grids take the shape of small clusters of laser emitters installed at the prow, stern, starboard and port sides of the ship so that they provide all-aspect coverage at all times. Their main purpose is to protect their ship from micrometeorites and space debris by emitting in short bursts capable of vaporizing impactors that have been deemed a threat by on-board sensors. Though a ship threatened by large (>5 meters) debris will often use evasive action, civilian laser grids can also fire in longer bursts to partially melt impactors and force them to change course. On modern vessel, laser emitters can be furthered clustered to provide a single, maximum intensity burst that is used for surface mining or wreck reclamation. The wavelengths of civilian laser grids are fine-tuned to provide the best balance between potential health hazards and power conservation, with most of them including software safeties preventing the bursts from being maintained for too long. Under common spacefaring regulations, a spaceship using its laser grid is legally obliged to broadcast a specific warning signal. Virtual reality interfaces for helmets and open cockpits always display the area within which laser grids are being used in bright coloured circles. When a ship with active laser grids travels through a thick dust cloud or debris ring, the constant bursts from its emitters accompanied by melting debris create a striking visual effect, as if the vessel was equipped with some kind of energy field.

Civilian grids can be mounted on very small frames, the tiniest of which are laser-djinns, small drones that roam around civilian installations and remove debris or stray asteroid fragments on their own.

Military laser grids are greatly upscaled versions of civilian ones, with all software safeties removed and much stronger lenses. Installed on gimballed turrets, they can be used in a defensive or offensive role. As a defensive tool, they are geared towards firing rate and gimballing speed. Against a single missile, laser grids will try to melt through its outer armour to make its engines detonate. Against a saturation attack, however, each emitter will focus on a single missile, aiming not for destruction but for disruption, blinding sensors, melting RCS thrusters and communication arrays. When the laser grid goes on the offensive, it switches to long, high-intensity and focalized bursts in order to ravage external ship structures -- radiators in particular are a prime target for laser grids. The smallest emitters can also be used as sensor blinders in very close range engagements. Military grids operate at much higher intensities and wavelengths than civilian ones, and can be outright deadly for drones or EVA personnel if used in a debris protection role. In Eloran and Terran space, military vessels are legally obliged to either carry a secondary civilian grid, or be accompanied by a support vessel when entering planetary orbit or high-traffic areas.

Laser grids are all but useless when going against Sequence vessels, as they do not use missiles and have thick organic hulls that regenerate faster than a laser grid can melt them. Anti-Sequence vessels will typically remove their grids before combat, either to focus on FTL performance or make room for a UREB mount.

Azur Effect

Written by Aramanae Talasea -- Azur Bureau of Geometry Drive Research.

In the early years of the interstellar age, there was the belief that we could not enhance the geometry drive, so to speak. That it was such a strange and incredible design that we, poor human minds, had no chance of upgrading it. That the original drive, as it had been discovered by Rani, was all that we would get. For a moment this idea held true. For the better part of three decades we had to make do with simple copies of the drive found in the Needle.

The first crack in the idea that the drive was a “finished” object came with the Starmoth Initiative and what they like to call “Butterfly drive” — a rather bad choice of words, I think, in the sense that the device that equips their long-range exploration vessels is a run-of-the-mill geometry drive. Its secret doesn’t hide in the crystal itself but within the complex arcanes of geometry jump calculations. Through complex mathematical tricks, the Starmoth Initiative managed to drastically improve the long-range accuracy of their drives, all the while decreasing their requirements in terms of computing power. Quite a feat, despite the shortcomings of the Butterfly drive — namely, that its vastly improved long-range performance goes alongside a massive downgrade in short-range capacity.

The crystalline cube itself is as mysterious as it’s ever been and we can barely understand, let alone modify its structure, because for all intents and purposes it wasn’t created by humans. In fact, if we take Rani’s latest theories at face value, it wasn’t created at all. It’s a prime mover, an effect without a cause. We can’t influence that. We need to work on the rest, on what’s human, on the web of mathematics surrounding geometry translations. The Starmoth Initiative paved the way for this and I like to think that we reaped a small part of what they so patiently sowed.

There is a way to drastically alter the efficiency of a geometry drive. Instant geometry translations work, but they amount to brute-forcing a problem that can also be bypassed. There is a loophole in the complex corpus of equations use to calculate a translation. Something even Rani’s talent overlooked. A tangent.

We call it the Azur Effect.

A ship submitted to the Azur Effect doesn’t exactly translates to another point; rather, it skims the contact point between dimensions, slipping right under the surface of reality to re-emerge a hundred lightyears a away. Effective range is greatly enhanced at little to no additional computing cost. Sequence interdiction and black hole interference don’t apply any longer. Temporal jumps like the one Zero Fleet suffered from are no longer a danger.It's safe. Efficient. Elegant. 

There is a cost to all of this, however. Where a regular translation is innocuous, the azur effect translation submits the ship to ill-understood forces that manifest themselves under the shape of violent mechanical stress that can and will rip away the hull of any regular starship. The only way to prevent this is to equip FTL-capable vessels with “dimensional sinks” — external appliances that drain the excess force away and out of the ship’s frame. Empirical results show that dimensional sinks work best when they take seemingly aerodynamic shapes, effectively adorning our ships with wings, winglets and streamlined fuselages.

For the first time in the interstellar age, the geometry drive is going to dictate the shape of a spaceship.

NASA/JPL, "Planets of horror" series. 

Deep Sky

The term "deep sky" refers to a part of the atmosphere that is often neglected by spacers yet is almost as important as low planetary orbit in the day-to-day operations of the space age. On Earth, the deep sky is a 90 kilometres thick layer extending from the lower stratosphere to the Karman line, the legal definition of the outer space border. On other worlds that may have different atmospheric layouts, the deep sky area is delimited by the envelope within which unassisted breathing is impossible (if applicable) but regular aerodynamic flight is possible. The deep sky, much like low planetary orbit and beyond, escapes the usual definitions of property and communal sovereignty on most worlds and is instead considered as a common ground, abiding by regulations similar to those that govern international waters on Earth. In a strange but ultimately understandable turn of events, on most worlds the deep sky is much lesser known than planetary orbit, owing to the incredible complexity of meteorology and climate on alien worlds.

Denizens of the deep sky straddle the limit between spacers and ground dwellers. In many ways, their environment is closer to space than the surface in terms of living conditions, with unbreathable air, limited aerodynamic flight at higher altitudes and high levels of radiation exposure on planets with weak magnetic fields. However, while a spacer is bound to spend long amounts of time away from a gravity well ("Once in the stars, forever married to the void" as per the Eloran saying), a deep sky dweller shares their life between the far blue sky and the surface. A very specific culture surrounds communes and cooperatives operating in the deep sky area, one that owes both to the "garage aerospace" ethos of the late interplanetary age and the test pilot ethics of the industrial era.

The main inhabitants of the deep sky are q-sats or pseudo-satellites.

A pseudo-satellite is exactly what it says on the tin: a vehicle that pretends to be a satellite while never bothering to be launched into space. Q-sats are often helium or vacuum airships that float at the upper edge of the stratosphere, using jet stream winds to travel around the planet or ascending to higher layers to remain immobile above their ground area. As they are solar-powered, q-sats may remain in flight for extended periods of time without servicing, sometimes months or years. Q-sats are very numerous in human space albeit it is somewhat hard to determine how many of them are in service, as they are less legally constrained than space satellite and as such only registered by local jurisdictions. They only require basic ground facilities and mobile tracking antennas to be operated, making them accessible to virtually any cooperative. They are often deployed on Venus-like planets as scientific outposts.

Pseudo-satellites are mainly used as communication relays and remote sensing devices. Though more exposed than regular satellites, their cost makes them very easy to replace. Their ability to loiter above a specific area without having to remain in a far geostationary orbit makes them ideal for civilian imaging as well as ad-hoc communications platforms on worlds with limited infrastructure. Remote sensing pseudo-satellites are very appreciated on worlds with significant high-altitude cloud cover such as Okean or Vyiranga where orbital platforms have trouble getting direct surface imaging in the visible and near-infrared spectrum.

Their close brethren are highflyers.

A highflyer is an unpowered aircraft that ascends to the upper atmosphere and then uses the local jet streams to remain in flight for extended periods of time several dozen kilometres above the surface. Highflyers are incredibly light, with their pilot or AI systems often representing the heaviest part of the aircraft. These gliders are made of carbon compounds weaved with an organic substance known as "pearl wood" often imported from the coral seas of Elora. Highflyers serve a different purpose than pseudo-satellites albeit they operate at similar altitudes. Most of them serve a scientific role, circling a planet to collect data on high altitude phenomena, observe storms from above, capture transient sylphs or blue jets on camera and sample lifeforms living at the edge of space. Highflyers are very common on high-pressure planets such as Okean, where the thick atmosphere enables them to keep bouncing between layers to keep their momentum.

A few cooperatives have been repurposing highflyers as mobile launch platforms for "all-in-one" nanosatellites carried aboard small integrated rockets attached to the belly of a stratospheric glider. Such nanosatellites are often used in tandem with highflyers in their scientific ventures.

On the faster, meaner side of things are Karman skimmers.

Karman skimmers take the shape of hypersonic, scramjet and aerospike-powered vehicles guzzling organic fuel and designed to straddle the thin border between high altitude aircraft and space shuttles. In the interstellar age, they occupy a rather strange niche as the only kind of aeroplane that can somewhat threaten spaceships. The idea behind Karman skimmers is to combine the advantages of space-based weaponry in terms of firepower with the laser diffraction and ground-based fire support offered by a planetary atmosphere. Such vehicles are meant to ascend to the edge of space where friction is minimal, fire their payload, then perform a steep dive to take cover from counter-battery fire in the troposphere.

The combat capability of Karman skimmers is doubtful, to say the least, and while there isn't a lot of usable examples, the Long War of Mars has shown that attacking FTL-capable spaceships with converted civilian spaceplanes is nothing short of suicidal. Modern Karman skimmers might be interesting in terms of payload optimization, however, given that they eliminate the need for an ascend module on long-range missiles which might give a much-needed edge to FTL torpedoes.

A more peaceful version of Karman skimmers - and as far as we know, more useful - are Skyhook subways.

Skyhooks are one of the most widely used means of surface to orbit transport on highly to moderately developed planets. They rely on cheap suborbital vehicles that carry a payload up to the end of the skyhook's cable to be reeled into space. Depending on local pressure and gravity conditions these vehicles may adopt either vertical or horizontal take-off/landing profiles. Though most of these "Skyhook subways" are drone vessels following exceedingly regular schedules, a few of them are piloted vessels. To sit in the cockpit of a skyhook subway is often reserved to ageing spacers with health issues preventing them from living and working in zero-g any longer. By volunteering as occasional skyhook subway pilots, they get to experience the thrill of grazing the edge of space for a short amount of time, gazing into the colours of the deep sky once again.

Finally, come the most elusive deep sky denizens, the surface to orbit airships.

However odd it might sound, the idea of carrying a payload all the way up to low planetary orbit with an airship is relatively doable, if one doesn't mind the lack of efficiency. The mission profile of a surface to orbit airship ascent encompasses the entirety of the deep sky. First, the payload is transferred to a stratospheric airship that ascends towards a pseudo-satellite station located in the higher stratosphere, where it connects with a space-capable vacuum airship that then ascends over the course of several days at supersonic speeds through the quasi-vacuum of the high planetary envelope. At the end of its journey, the vacuum airship effectively becomes a small starship capable of docking at a space station. It is then capable of going down towards the atmospheric station on its own.

Surface to orbit airships have undeniable aesthetic qualities, but their appeal doesn't stop at their elegance. Their ascent and descent profiles are the smoothest of all surface-to-orbit vehicles, only surpassed by a space elevator train. On planets devoid of such equipment, surface-to-orbit airships are ideal for payloads or passengers that are too critical to go through a regular ascent, even one carried out by a suborbital vehicle. 

Image credits, in order of appearance.

Airship by Jean Philippe Chassel, GNU license // Perlan glider by Airbus aerospace, all rights reserved // SR-71 and X-15 pilot, US public domain (USAF and NASA, respectively) // surface-to-orbit airship, JP aerospace, all rights reserved.


The Star-In-A-Mist, or Pseudonigella stellaris, is the plant that produces hyperdimensional crystals used in geometry drive manufacturing. It seems to derive from the Love-In-A-Mist, or Nigella damascena, touched by the influence of the original geometry drive when Rani Spengler first examined it. P. stellaris is almost as mysterious as the original drive itself: though its biology still owes a lot to N. damascena, the way it excretes crystals with its flowers leads some scientists to consider it as a new form of life altogether.

P. stellaris thus looks like a 15-20 centimetres tall chlorophyll-based plant with pinnately divided, thread-like leaves. When the flowers bloom in early Earth summer, however, P. stellaris starts producing millimetre-long crystal structures that run around the underside of the petals. These crystals have the same colour as the petals, ranging from pale purple to clear blue. Much like the geometry drive itself, they gleam very slightly in the dark after absorbing energy under the shape of light or ground vibrations. These crystals bear the unique property of being four-dimensional structures: though they can interact within our three-dimensional space, they are in fact the three-dimensional pattern of a four-dimensional object. It is expected that this exceedingly peculiar nature is what enables these compounds to bend the space-time continuum when arranged as a geometry drive. One of P. stellaris' colloquial names is "geometry flower".

Much like its mundane counterpart, P. stellaris isn't particularly hard to grow in terms of climate range and soil composition, but several additional parameters have to be taken into account. P. stellaris requires incredible amounts of energy (for a plant this size, at least) in order to grow its crystals. In the presence of a regular day-night cycle, P. stellaris is very quick to deplete the soil. It is generally not advised to grow P. stellaris near other valuable crops: the geometry flower will compete with them and invariably end up killing them. A single P. stellaris flower contains between two to three milligrams of hyperdimensional crystals: the average geometry drive requires to harvest about a thousand flowers, while its maintenance consumes ten to twenty flowers a year.

Inhaling or ingesting P. stellaris while it is blooming isn't advised: though it is a rather common practice among navigators and gardeners, it leads to feelings of weightlessness and irrealism, where the subject may briefly feel as if they were in two places at once.

P. stellaris can be adapted to the majority of habitable planets: one way or another its ability to create hyperdimensional crystals gives it more resilience than its regular counterpart. The differences in the visible and invisible spectrum on the host planet may induce variations in crystal thus geometry drive quality, explaining the dark red drives of Ishtar or the pale blue crystals of Azur. Low-gravity and artificial lighting don't seem to be a problem but P stellaris' unreasonable requirements can be quick to bankrupt the energy budget of a station. In any case, the genetic code of P. stellaris is a well-kept secret and the seeds are as precious - and as protected - as high-end fusion drive components. P. stellaris seeds and crystals are among the rare artefacts that would make someone truly rich in human space.

There have been many attempts at forcing other plants to produce these crystals: none of them has resulted in much more than horribly deformed plants and highly explosive petunias...as far as official records are concerned, at least.

Show more posts

All content in the Starmoth Blog is © Isilanka
Written content on Starmoth is distributed under a Creative Commons Attribution Non-Commercial Share-Alike 4.0 license