Artificial Gravity

Artificial gravity fields, colloquially known as AG fields, are a means of generating gravity primarily for use in spacecraft and microgravity environments. They take the form of a metal plate usually inserted beneath the deck, which acts as a quantum resonator when powered. The oscillations interact with one-dimensional strings at the Planck length, causing the condensation of gravitons, the carrier-particle of gravitational force. These fields can be tuned very precisely by modulating the amount of energy passing through them, and are limited in scale, meaning that they cannot cover too large of an area before they begin to break down.
These fields can also be inverted, acting as gravity repulsors that allow large masses to float weightlessly.

Batteries

Battery technology in the 2600s is very advanced, with very high energy density and power output in the megawatt range for handheld devices and weapons. Shipboard battery banks can store the combined output of multiple nuclear fission reactors for long periods of time and are able to discharge them very rapidly. These primarily use carbon-nanotube supercapacitors in solid-state systems.

Communications

Due to light-speed delay, messages sent via laser or radio can take decades or more to cross interstellar distances, making them impractical for maintaining a long-range communications network.
The only means of transmitting data between two distant planets instantaneously is through the use of quantum satellites. These satellites are expensive and very difficult to manufacture, and their scarcity results in many non-priority data packets remaining in the comms buffer for extended periods of time, waiting for a transmission window. These are primarily used by governments and militaries, but satellites owned by private corporations do exist, though they are prohibitively expensive to rent.
The satellites have data storage units that are quantum-entangled, meaning that changes made to one are instantly reflected in the other regardless of distance. These data storage systems must be twinned in a lab, where the particles responsible for representing data on the drives are paired off, then both are shipped out to be installed in their respective satellites light-years apart. When a value changes in one data storage device, it is instantly reflected in its twin. The size of the files that can be sent in this manner is limited to only a few kilobytes at a time.

Drones

While drone technology does exist in the 2600s, it generally doesn’t see widespread use, as the delays incurred by distances of light-seconds or light-minutes at the ranges that ships often engage would result in the remote-operated vehicle receiving outdated or incorrect instructions. Machine learning systems operated by the UNN are not advanced enough to function without input from an operator, and UN law prohibits the use of automated weapons, meaning that almost all vehicles are manned by a human operator. Exceptions are spotters and scout drones used by armored vehicle crews on the ground, where such delays are not incurred.

Genetic Engineering

In the 2600s, gene-editing is a common treatment for illnesses. Cancers can be eliminated very quickly using gene therapy, birth defects can be edited out in the womb, and diseases like HIV and sickle cell anemia have been eliminated.
There are limits imposed on genetic engineering that has no medical purpose, however, such as using the technology for eugenics. Designer babies are permitted but are regulated by law, with only cosmetic and health-related modifications being allowed.
This extends to modifying soldiers for combat purposes, which violates the Yellow Sea treaty. The treaty was penned after the disastrous effects of body modification and CRISPR gene-editing on Chinese soldiers during the Sino-American War.

Molecular Forcefields

Molecular forcefields are used to create energy barriers that allow solid objects to pass through them, but which contain the atmosphere, allowing hangar bay doors and airlocks to be open to space. This is achieved through the creation of an energetic lattice that is projected over the desired area, fine enough that air molecules cannot pass through it. This field breaks down quickly when any kind of force is applied, quickly reconstituting as soon as that force is removed.

Prosthetics

Prosthetic limbs and organs that can completely replace their lost or damaged organic equivalents are a common sight, especially in the Navy where such injuries are a more frequent occurrence. These include vital organs such as the heart and lungs, eyes, ears, digits, limbs, and more.
Prosthetic limbs are made from lightweight polymers and are printed to specification, attaching seamlessly to the user’s body following a 3D-scan of the area. They are anchored to bone where possible, using a socket system that is grafted onto the body, which is then covered over by a soft gel layer that prevents direct contact with scar tissue that could cause chafing or irritation. Tiny wires are then connected to the severed nerves, giving the user very fire control over the prosthetic, along with simulated tactile sensation if desired. The design of these prosthetics varies from skeletal limbs designed solely for function, to more elaborate recreations of the missing limb that simulate its original form. Prosthetics are powered by battery banks that are built into their housings, which can be partially recharged through the inertia of motion, giving them very long lifespans.
These limbs are quite a lot stronger than their organic predecessors, and they are often limited through software to comply with the Yellow Sea treaty, which prohibits the creation of weaponized prosthetics. The same treaty also prohibits the amputation of healthy body parts for the purposes of augmentation, though some unscrupulous organizations manage to find creative ways to get around these limitations.

Superlight

Superlight is the means by which vessels achieve faster-than-light travel, allowing them to cross vast distances almost instantaneously. Superlight drives are complex devices built on highly theoretical mathematical principles that are properly understood by only a handful of physicists, but the fact that other species have developed similar drives suggests that the underlying principles are sound.

In our Universe, no object can travel faster than the speed of light, as doing so would require infinite energy. Even small fractions of light-speed are difficult to attain using conventional propulsion methods, and would not solve the problem of crossing interstellar distances taking hundreds or thousands of years.
This limit can be bypassed by exiting our Universe entirely, entering a different reality with different laws of physics. Exactly what these laws are is poorly understood. The speed of light in this alternate space may be much higher than in our own, objects might be massless, time may flow at different rates, or two points in space may be closer together. Whatever the cause, the result is the ship exiting this alternate space having crossed a large distance in our reality. The distance traveled is proportional to the energy expended during the activation of said drive, and the mass of the object.

Superlight drives consume a great deal of energy, and one or more nuclear reactors are required to charge them up over a period of weeks or months. The greater the energy output of a vessel, the further it can go with each jump, but the mass of the vessel and its charge time must also be taken into account when calculating the overall travel time. During charging, the vessel will coast in realspace, waiting until it generates enough energy for another jump.

The process of a superlight jump begins with the jump calculation. These calculations are only estimations, as there is no way to measure or chart the extra-dimensional space through which the vessel will travel. The expected distance and energy expenditure are used to determine the exit point, with greater distances giving less precise results. For this reason, it is unwise to exit in close proximity to a celestial body such as a planet, as calculation errors may bring the vessel dangerously close. Many ships prefer to exit some distance from their destination, using their conventional engines for the remainder of the journey. This problem diminishes over shorter distances, with very short-range jumps being far more precise.
Once the calculation has been performed, the drive is activated, expending the energy in its battery banks very rapidly. It uses this energy to create a superlight manifold around the vessel, a field that extends some distance from the ship, and which will carry along any objects within its bounds. This effect, also known as a superlight wake, is used by UNN Jump Carriers to pull their support fleet along with them.

At this point, the ship leaves conventional spacetime, creating a small gravitational wave. The properties of this extra-dimensional space do not allow for the normal functioning of shipboard instruments, and so it cannot be measured or recorded in any way. Similarly, living nervous systems cease to function properly, resulting in various neurological effects including blackouts, seizures, nausea, and temporary paralysis. The experience can be very unpleasant but gets somewhat easier with frequent exposure. Passengers are often immobilized using automatic manacles and harnesses to prevent them from injuring themselves, and plastic bits are commonly provided to prevent the person from biting their tongue. Exposure to the energies of this space is only momentary, lasting a few seconds at the most, with systems resuming normal functioning upon exiting.

As the vessel leaves superlight, it creates a second gravitational wave, followed by a colorful cloud of gas that expands in its wake. This gas is the residue of the interstellar medium that was captured inside the superlight manifold prior to the jump, having had its properties altered by its interactions with extra-dimensional space. At this stage, the crew will still be recovering from the unpleasant neurological effects of the jump, which could linger for hours if the person in question has not built up a resistance. The autopilot system will therefore take control temporarily to right the ship and to run a system diagnostic, maneuvering to avoid obstacles, or activating defensive systems as necessary.

Tethers

Tethers, otherwise known as space elevators, are a cost-effective means of achieving orbit without using conventional propulsion methods. Cables that are thousands of kilometers long are anchored to the surface of a planet, and a counterweight such as a space station or a shipyard is attached to the other end, using the natural rotation of the planet to stay in a stable orbit. Crawlers carrying cargo or passengers can then make their way up and down these cables, dramatically reducing the necessary energy expenditure to get to and from space.

Earth has several orbital stations known as Terminus Stations that each serve their own respective regions of the planet. The American Terminus, for example, has several tethers that are anchored in regions of North, South, and Central America, acting as a hub for transport and cargo.

All of the orbital stations must remain above the equator, but tethers can be anchored in different hemispheres as long as each one has a counterpart in the opposite hemisphere. Passenger tethers are usually anchored in large population centers, while cargo tethers are more often located off-shore on artificial islands where oceangoing cargo ships can more easily dock.

There are also tethers on other important colonies, such as Mars and the Moon, where lower gravity makes construction cheaper and easier.

Weapons

Throughout the 2400s and2500s, caseless guns supplanted traditional firearms and were the standard-issue weapons for military and police forces through UNN space. These usually took the form of top-loading assault rifles and PDWs, marksman rifles, and sidearms. The advantages of these weapons were their light weight, cheaper ammunition, and simplicity of design, as no ejection system was required for spent casings. Although these weapons have mostly fallen out of favor with the UNN, they still see widespread use with Planetary Defense Forces, civilians, and in specialized roles such as suppressed or subsonic weapons.

In the early 2600s, the XMR platform was adopted as the standard-issue weapon for UNN forces. The XMR, or the X-Species Modular Rifle, is a weapon platform designed for versatility first and foremost, with the intention of its components and ammunition being interchangeable between frames of different sizes that can accommodate multiple species of varying statures.
In its base configuration, the XMR is a railgun with a bullpup design to maximize the available barrel length. It has a pair of magnetic rails that are charged by an onboard battery pack housed in the stock, and can accelerate a 50x6mm tungsten projectile to speeds of up to 2km/s, the recoil of which is managed by a sophisticated system of springs and dampeners.

The base of an XMR is the frame, which contains the core components of the weapon such as the trigger assembly, the receiver, and a magnetic rail. While the rail included with the frame is small, ensuring that the weapon can be configured as a PDW or a handgun variant depending on its size, its primary function is merely to pass off the projectile to arrays of magnetic coils in the attached barrel.

The barrel length and coil density then determine the muzzle velocity and kinetic energy of the projectile. Using different lengths of barrel, a frame can be converted to fill almost any battlefield role, from marksman rifles to light machineguns.

Other attachments include stocks, magazines, optics, forward grips, battery packs, gun shields, bayonets, and more. The weapon can be very finely tuned to the user’s needs, and parts can be replaced quickly in battle if need be.
As well as using interchangeable parts, the receiver can be removed from the frame and replaced with an equivalent designed to accept a plasma canister instead of a magazine. Using the same rail and coil assembly, this plasma can be magnetically contained and fired as a projectile, which is especially useful when facing the handheld shield projectors fielded by Betelgeusians. This can be done in combat, although it is cumbersome and alternative methods of achieving the same results are in development.

Frames come in three sizes: small, medium, and large. All of the attachments and magazines are interchangeable between them, meaning that a large frame configured as an anti-material rifle and a small frame configured as an assault rifle can share ammunition. Small frames are intended for use as lightweight PDWs by human operators, or as standard rifles by Coalition members of smaller stature such as the Valbarans.

Medium frames are suitable for use by humans, while large frames are intended for the larger Borealan and Krell auxiliaries.

The XMR platform provides an unparalleled level of flexibility and power, able to penetrate up to 62mm of steel at optimal range. The ammunition is very cheap to manufacture, requiring no propellants,  but the platform is not without its downsides, the foremost of which is heat dissipation. Tungsten is very good at conducting heat, and much of the thermal energy generated during the firing of the weapon is carried with the slug, often partially melting it, which creates trails of molten metal in its wake. Even so, heat collects in the magnetic coils, which can result in them slagging under sustained fire, which in turn limits the fire rate of the weapon. This is especially true for light machinegun variants, with operators carrying several spare barrels on their person with the expectation that many will melt and become unusable. While the coils are insulated and the XMR platform is rated for vacuum, its thermal performance in open space is notably worse than in atmosphere, requiring the operator to pace their shots to avoid overheating.
Overpenetration is a natural consequence of the weapon’s power, and although the voltage can be dialed down to reduce the muzzle velocity, and soft-tipped ammunition can be used, caution needs to be taken when firing the weapon on spacecraft. For this reason, caseless weapons are sometimes still preferred for use during boarding actions.