One of the peculiarities of the Terran Stellar Republic is the diversity of worlds in terms of the level of technology supported on each member world, referred to as that world's tech level. The Core Sector worlds are all very high TL systems, but farther from the Core Sector, fewer worlds are able to make that claim.
The reason is that Tech Level is more than just having an appropriate blueprint and stuffing it through an automated manufacturing plant. To manufacture at progressively higher tech levels is increasingly complicated and relies on a larger and larger infrastructure of materials construction, technological support, and user capability. A medieval blacksmith can add carbon to iron and make steel, but he can't dope it to any percent, much less with four decimal places precision, nor meld it with other metals in the precise amounts required to make a powergun barrel. A vacuum tube computer will spend years calculating and burn out every tube and still never approach even a Jump-1 calculation.
Colonies are generally seeded at the highest tech level the colonists can afford, rather than the highest level that the homeworld is able to produce. Sending along TL 15 manufacturing capability in a single ship is both wildly expensive and creates an economic rival right away rather than a potential market for your own goods. Importing higher TL conveniences is a major source of trade.
Residents of a lower TL system generally do understand higher TL equipment, and can operate it normally, even if they don't have the tools and equipment to repair them. This is why lower TL medical aid incurs a negative DM when working on a patient with high TL implants.
Tech level zero is the Stone Age. Hitting people with things you find on the ground. Language is primitive, and writing consists of what you scratch on a cave wall. Getting food is gathering up plants you find and stabbing animals with a pointy stick. Manufacturing consists of tying a likely-looking rock to the end of a good stick with some vines. Coincidentally, this represents the peak of hunting and weapons technology. The peak of TL 0 is being able to make a fire. About the only way to achieve TL 0 is to crashland on a virgin planet.
Tech Level One begins with the ability to work metals. Melting rocks and casting the liquid runoff into useful shapes means you don't have to find a sharp rock when you want to hurt someone. Manufacturing is cottage industry, by and for oneself or your immediate community. Large construction projects are major undertakings with everything done by hand. The basic princples of simple machines develop in this TL, so wedges, pulleys, levers, and so on allow builders to make impressive structures that last, though it requires as much sweat as brilliance. Animals are used for land transportation and raw power, pulling wagons or sledges, allowing materials to be transported in small quantities.
Writing also becomes common in this TL, starting off mostly as paint on animal skins or flattened reeds or whatever flat surface can be made; paper develops later in this TL. Communication is both written and oral, with important things written down, but messages to the masses delivered by crier. Oceangoing vessels are primitive coasting craft, though some brave souls are clever and hardy enough to make crossings out of sight of land. Most, though, 'fall over the edge'.
Few choose a TL 1 life, though some ascetics claim that their religious tenets forbid anything not made by their own hands.
Tech Level 2 represents the Renaissance period on Earth. Weapons are more complex than before, crossbows and primitive black powder firearms and cannon, though most will carry something reliable like a sword or knife. Tools and construction are simple, with everything done by hand, and quality varies with the skill and integrity of the builder, using hand tools that can be made by any smith with iron smelted or bought in bars or ingots. Ships ply the oceans with the expectation of success, using complicated sails and rigging, navigating by sun or stars, using a compass, sextant, and charts.
Tech Level 3 begins the Age of Reason. Technologically, the tools are still being made by hand, but they're more complicated and better made. Steam is being used to power large things that move, ships and trains, enabling mass movement of resources, so that manufacturing can be centralized and economies of scale can be realized. Centralized construction standardizes the end product, though defects aren't uncommon. Steam in factories automates the construction of simple products, marking this as the beginning of automated manufacturing. Weapons are advanced versions of the previous TL, most gains are in ease of use, reliability, and service life. Electronic communications over long distances by telegraph are in their infancy, messages are still delivered by mail, which usually is regular and reliable in TL 3 areas.
Tech Level 4 is the full force of the Industrial Revolution, bringing basic manufactured products from shoes to shovels to the world at large via steam-powered oceangoing vessels. Complicated economies interconnect the planet, though long range electronic voice communication is only just developing. The world is linked by simple long-range communications, allowing short messages to be passed. Anything complicated is still recorded on ink and paper, though the industrial revolution includes the true mass production of written material, allowing anyone with something to say to deliver a message to anyone willing to read. Literacy is almost ubiquitous among the educated classes, and even the uneducated classes are generally at least functionally literate.
Automated manufacturing allows parts for more complicated creations to be made en masse, even if the final products have to be hand-assembled, culminating in the assembly line. Industrial controls and advances in materials allow small parts to be made and when assembled into automatic firearms that can survive the rigors of use. Rotating steam engines fired by coal or oil, already in use in factories and ships, but the discovery of the properties of electricity provides a new use for steam. Rotating a turbine to generate electricity provides lighting that allows people to work later into the night, and to illuminate without the need for fire.
Electrification is almost ubiquitous by this time, and is used not only for lighting, but for refrigeration, as well as radio, which by now has reached a size where it is a viable consumer product. Advances in electronics applications are quickly capitalizing on the concept of radio, developing video recording and retransmission technology and radio detection and range-finding equipment that measures radio waves reflected from distant targets, the first radars. Portable radio is bulky, but when fielded, it becomes a force multiplier by allowing coordinated tactics.
The oil and coal-fired engines of the previous tech level are able to be built smaller without exploding, but need a different sort of fuel, and with electrical advances, internal combustion engines supersede horses as the primary light transport method. Rail and ships are still the first choice for massive and long distance travel, however an internal combustion engine-equipped vehicle can be built to traverse almost any kind of terrain without the need for tracks to be laid, allowing military vehicles with modern weapons to go almost anywhere.
Advances in modern weaponry allow rapid rates of fire and longer ranges, but now require more calculation than even the most educated gunnery officer. Developments in electronics conveniently allow complicated calculations to be carried out automatically at high speed, though the size of the equipment limits the places such devices can be used.
At the end of this Tech Level, investigation into the nature of matter results in atomic technology.
Developments in TL 6 expand in the areas of electronics, computing, and atomics. Modern power plants run much more efficiently with fission power, and though accidents happen until technology improves. Applications for aircraft are one of the main improvements, with jet engines, radio, radar, radionavigation, and weapons technology advancing quickly. Radios are found in almost every police and emergency vehicle, but are of limited interest for consumers. Missiles for combat evolve into rockets for extra-atmopshere travel, requiring computers to monitor the massively complex number of variables involved. This TL culminates in manned spaceflight.
Tech Level 7 is characterized by reliable spaceflight that puts satellites into orbit. Advances in computers and networking link the world, using satellites to expand communications past where land-based networks can reach. Most advances in this Tech Level are incremental improvements on previous Tech Levels rather than new technologies. Voice communication devices are smaller and more portable, becoming ubiquitous among emergency responders and available to civilians as well. By the end of the Tech Level, everyone who wants one has an electronic notepad and telephone with access to the planetary datanet. Rockets and aircraft carry more people and run more reliably. Land vehicles are likewise much more reliable and efficient than at previous Tech Levels.
Tech Level 8 is the lowest tech level that can support routine spaceflight. Any society past TL 5 can pave a landing area, but TL 8 is required to merge the complex array of infrastructure elements: radar, communications, air/space traffic control, space tech maintenance and repair (including routine repairs in space using primitive vacc suits), logistics, customs, and administration required to manage a spaceport successfully. Travel between stars is not yet possible, but a TL 8 spaceport can handle system ships, and provide rudimentary services for visiting starships. At this Tech Level, locally-built ships can seed habitats in many places within a system, powered by viable fusion reactors.
Terrestrial exploration is aided by a space dividend - life support equipment for vacc suits can be produced in small, standalone versions, allowing rescue and exploration in hostile environments - underwater or in fire and smoke or other hazardous atmospheres. Weapon advances include non-lethal items for crowd control such as stunsticks and stunners. Hover vehicles, which previously had limited applications and required large engines and fuel tanks for travel over a distance, are now commercially viable with fusion-electric fans.
Tech Level 9 is marked by the development of gravity manipulation, sometimes called contragrav or CG for short, particularly in reference to vehicles, but often referred to simply as grav. Of limited use in gravity as intense as a planet's surface, in space, grav thrusters allow ships to reach speeds that rewrite system transit timetables by orders of magnitude, and ideas about field manipulation seed the minds that will develop the Jump drive.
Small but intense grav fields combined with advances in fusion power miniaturization make portable laser weapons possible at this tech level, as well as laser-based transcievers that can reach ships in orbit. Previously, terrestrial comms had to relay messages to high gain radio antennas to reach beyond the lowest orbits. With advances in laser technology, defensive countermeasures also develop during this time, ablative armor (Ablat, similar to heat shielding on older spacecraft) can absorb laser energy, though it degrades the armor quickly.
True interstellar travel is possible now. A visitor to a TL 10 world will be able to visit a fully-functional starport and expect decent service, if not the best and most modern. Unrefined fuel and primitive or expensive repair parts may be the norm, but the needs of interstellar travel are supported by the local manufacturing base, and some will even support a Highport, a spaceport permanently in orbit, often supported by factory stations nearby in space.
Medical advances combined with miniaturization enable the development of implants that take a body beyond normal capabilities. Miniature radios, air filters, reinforced skin for extra toughness are among the enhancements that are supporeted by TL 10 facilities, more advanced implants require higher technology. Medkits can be permanently installed in vacc suits and related items, with biomonitoring that can provide first aid in an emergency, even to people with implants, if the medkit is as advanced as the implants.
Metabolic drugs radically affect first aid. Mortally wounded patients can be put into artificial hibernation without a cryoberth in order to retard the affects of disease or injury while transiting to a medical facility. Cryoberths themselves also appear at this TL. Other high tech tools become ubiquitous at this TL: RF probes, portable fusion generators, data wafers, and so on.
Other advances in miniaturization allow computers to be placed almost anyplace, allowing weapons to process biometric data and only work for the authorized user. A TL 6 firearm can be fitted with every sort of scope, rangefinder, and gryroscopic stablization advance, and biometrics, and with TL 10 materials all together making a very advanced weapon. Spacecraft armor can be made from denser alloys, and new laser resistant materials both reflect energy and absorb/disperse what can't be reflected.
Tech Level 11 opens up stellar travel with the first Jump-2 capable ships, advances in computing and navigation allowing computers to correctly jump twice as far as previously possible. The first true Artificial Intelligences are being developed, enabling even greater complexity to be managed by people with little training. Expert systems enable anyone who can operate a computer to execute programs that will fly a starship for them, though this is not recommended. AIs are fitted to common utility robots, creating semi-autonomous drones that can load cargo, repair shipboard systems, assemble habitat modules, or perform other somewhat complex tasks, though medical AIs are not safe yet.
Medical technology enables physical characteristic augmentation at this level, though only for the very rich. The latest method of medical treatment for recovering from injuries is to put someone in a cryo chamber and jump their metabolism up 30 times normal. Intravenous nutrients and intense cold prevent tissue damage from this process - doing it without medical supervision is a messy sort of suicide.
TL 11 Starports can repair and replace higher rated J-drives. Portable, lightweight Radio Frequency transcievers can reach any orbit reliably. Defensive technology advances past armored vacc suits to true purpose-built combat armor. Massive and unpowered, it provides substantially greater protection than possible at lower levels, making this the lowest TL that can support military manufacturers who even hope to contend. For those that can't afford the hefty price tag of combat armor, the clamshell is available, giving as much protection, but only to the front and back thorax, head, arms, and legs are unprotected. Because of the difference in cost, TL 11 clamshell armor is generally used by any military unit that doesn't actually involve vacuum, meaning only Marines are likely to have experience with Combat Armor.
The first production powerguns in the hands of fielded forces appear at this TL, quickly becoming synonymous with destruction - unlike other weapons, powergun blasts breach any sort of armor, rendering it useless with only one or two shots.
Artificial Intelligence is advanced enough now to add additional range to Jump prediction, to pilot simple combat drones, to perform lifesaving surgery, and to control atmospheric equipment effectively, revolutionizing weather control and terraforming. Heavier powerguns are made possible by the same advances in gravitics that finally allow grav field equipment to operate lightweight vehicles in a planet's gravity well. The Air Raft needs only a small thruster to propel the vehicle to very high speeds, but the contragravity lifter can only counteract so much weight, so they do not replace standard surface-to-space shuttles.
Spacecraft sensors reach their peak at this level, able to detect in the RF spectrum, the gravitic spectrum, and sensitive enough to detect neural activity. Weapons continue to advance, powergun-derivative hellbores replacing older technology in military ships. Screens are developed to try and mitigate the damage of this powerful new weapon, but only partial success is achieved.
Advances in grav equipment and thrusters allow spacecraft to enter atmosphere more easily and even travel underwater, allowing them to refuel much more easily. Combat armor is fitted with power servos, making Battle Dress the ultimate in personal protection, though few can afford to field the multi-million credit suits in any volume. Gauss weapons using the TL 6 ideas and TL 13 materials come to the high battlefield, high speed superhard projectiles capable of penetrating Combat Armor without breaching ships' hulls entirely makes boarding actions feasable again, though desperate defenders with powerguns make boarding a nightmare in any case, and powergun manufacturers develop field-luggable powergun artillery while vehicle-mounted powerguns grow more efficient and more deadly.
Medical implants are now good enough to enhance intelligence and vision, though it makes head injuries almost impossible to treat at any but the highest TL hospitals.
Artificial Intelligence and robotics are finally able to produce humaniform robots, though only as a toy for the very rich. AIs can now direct nanomachines to repair rips and tears in seconds, making the robots, as well as other structures with repair nanobots, hard to damage.
Improved manufacturing techniques create duralloy, a superdense steel that can withstand incredible punishment, allowing warships to survive space combat for much longer. The development of duralloy allows a huge number of older technologies to improve, grow smaller and easier to use, though few other breakthroughs occur.
Advances in gravitics and plasma technology allow development of a shoulder-fired hellbore, but the cost is prohibitive for widespread fielding. Sales and manufacture are strictly regulated, though they show up often enough amid stolen weapon caches and in the hands of the rich-and-desperate.
The pinnacle of technology in the Terran Stellar Republic, TL 15 worlds can synthesize anagathic (anti-aging) drugs, clone limbs, or create substantial physical and mental augmentations. Neural and biological activity scanners shrink to handheld and backpack-sized units. Black Globe generators make use of grav technology in new ways to absorb incoming energy, though it renders the ship useless. Using Black Globe generators is impossible in a gravity well or under thrust. On the ground, infantry units can use grav floaters, sort of like a contragrav segway, to bypass hazardous terrain and obstacles.
At this TL, computers and weapons using the most advanced technology are further refined, with prototype units of grav and grav-assisted tracked armor appearing armed with powerguns and hellbores, efficiency boosted by the most advanced AIs.