Standard Starship Sensors
This a breakdown of typical starship sensors and a general overview of how they work and what they do. These are standard systems on all interstellar ships, except where noted or restricted.
Short-range sensors are also often referred to as scanners or tactical sensors (especially on military vessels). They provide real-time information on nearby objects. They are more detailed than long-range sensors and are generally “active” sensors. The range of short-range sensors can vary greatly. Generally larger ships can mount larger, more powerful arrays with longer range, but the power of these sensors is mostly determined by the role and likely use of the vessel. Some ships only need sensors for navigational aid, while others need important and detailed combat information. Standard range for a large civilian vessel is 1000,000 miles. Standard tactical sensors on military vessels can have twice that range or more, usually about 250,000 miles. Short-range sensors are useless at FTL speeds or at high sublight speeds (over .05 C, or anything more than 5% of the speed of light). The most advanced forms of these sensors can reach millions of miles but generally most manufacturers limit them to 370,000 miles. Any longer range than that and the data is considered worthless because there is a four-second lag or more. Military ships generally max out at 500,000, and operators are trained to compensate better for lag than most civilian sensor operators.
Standard short-range sensor package includes:
Radar: Typical radar, mostly unchanged for the last 500 years, is still a standard sensor on all ships. It works well in open space, able to detect objects as small as a soccer ball. However, it is often disrupted by high radiation surges, is unreliable in areas of dense particulate matter; such as a nebula or asteroid field (which are loaded with dust and micrometeorites), and easily jammed. The benefit is that they can detect things that have no electromagnetic field, emit no heat or are visually “invisible.” Most radar in use provides a omni-directional globe of information that the ship’s computer feeds into a heads-up display or overlays onto view screens or into flight helmets, or is incorporated into some other display. Separate, dedicated radar screens are rare.
Thermal Detectors: These sensors provide detailed thermal information and are able to detect high amounts of heat (in excess of 212 degrees Fahrenheit) even through hull plating, and can tell whether a ship’s power plant is active or not. Thus, eliminating the ability of an enemy to detect heat emissions is a vital part of stealth gear. Most stealth-capable vessels (a rarity) do this by shunting heat into shielded “heat sinks” but this is only a temporary measure, usually giving heat stealth for only a matter of hours. These heat sinks are often dumped close to a planet’s atmosphere, where they are usually mistaken for meteorites burning up in atmosphere (which happens thousands of times per day around virtually every planet).
Transponder Signal Receivers: This is less a sensor and more a form of automated communications. All licensed ships have a transponder of some kind or another that broadcasts their identity for both other ships and law enforcement agencies. Information is limited to ship class, name, registry number and home port or owner. There are numerous ways to hack, duplicate and disable these transponders. However, being caught having tampered with one will result in ship impoundment and heavy fines…and can result in increased criminal penalties when added onto other crimes. They are also limited by the same limitations that affect radio transmitters.
Wide-Spectrum Visual Scanners: These sensors detect and display infrared and ultraviolet light by either passively scanning for anomalies and warning a sensor operator when one is detected, on a dedicated WSVS display (often paired with thermal detectors), or through a transparent overlay on the heads-up display or primary view screen. These systems are also sometimes referred to as LADAR.
Standard Targeting Computer: Limited to ships with weapon systems, this system uses data from other sensors to target enemy ships and assist in aiming of weapon systems. The computer eliminates the massive penalties that would be in effect for attempting to fire at ships moving at such high rates of speed over large distances, and quickly calculates a targeting solution and locks on to targets: Limited to the range of the guns. Each computer is calibrated to the type of weapon in use and each weapon has its own targeting computer. Bonus: +2 to strike. Eliminates all movement penalties.
These sensors work on a much larger scale than short-range sensors, and are generally calibrated to look for large objects far away. They generally have limited utility at short-range, are low-powered and almost always passive in nature, meaning they cannot be detected when in use. Long-range sensors are usually measured in millions of miles, with usually a max range of several astronomical units (A.U.). An A.U. is the distance from the Earth to the Sun, about 96 million miles.
Digital Telescope: The only long-range sensor that is standard on all vessels is the digital wide-field telescope, which tracks stars and large astronomical bodies for purposes of navigation. Since this is essentially a telescope, its range is almost unlimited. It can pick out planets and large moons from 5 A.U. and can detect all visually detectable stars (as well as compare them to a map of known star positions). More refined telescopes are mounted on survey vessels and scout ships, often greatly increasing the range at which they can detect planets, large moons, and much smaller objects in motion.
Mass Detectors: These are gravity field detection sensors that detect the effect of heavy objects on space-time. Except for photons and ships in a negative mass field, all physical objects have mass. That mass, even in very miniscule ways, warps the fabric of space. The heavier the object, the more it warps space, causing objects to be drawn towards it. Additionally, the large the object, the more easily it is detected by mass sensors. Very large masses, such as large moons, planets, and stars, are usually described as having a gravity well. Gravity wells are detectable at twice the range of normal, lower-mass gravity disturbances. Mass detectors do not provide any information except mass, but they have incredibly long range and are passive sensors. They actually detect the “pull” of other objects on the vessel on which they are mounted, even if that pull is extremely small. Another benefit of mass detectors is that they are not affected by line of sight. They can detect masses behind moons and planets (but not stars…too much gravity distortion). Mass detectors are limited more by the size of an object than by range. Most mass detectors can’t detect anything smaller than a million tons at ranges of over an A.U. This means only large capital ships (such as Arkhon Motherships or Protectorate carriers and battleships) are detectable at very long range. However, groups of objects, like a fleet or asteroid swarm, will often count as one mass, and are detectable.
Electromagnetic Field Detectors: EMF detectors have been around since the late 20th Century. But by this time, they are mounted on ship sensors and have extremely long ranges. Anything that has a power source or sufficient mass to absorb a sizable amount of solar radiation has an electromagnetic field. All ships have one, as do all planets and most moons. These signatures tend to be extremely unique, almost like a fingerprint. EMF detectors are generally sensitive enough to allow a ship to identify a type of vessel from millions of miles away. With enough detailed information programmed into the system, a good sensor operator can even identify specific ships of the same class. EMF detectors can also pick up energy spikes and radiation surges; such as weapons firing, nuclear explosions or powerful rail guns or gauss cannons firing. EMF detectors work equally well at short range as well as long range, making them the standard go-to sensor for most vessels. It’s what people tend to look at first. EMF detectors can be “spoofed” by larger electromagnetic fields, artificial EM-emitters, and in some rare cases, some ships can “clone” the EM field of another vessel temporarily. Many ships also carry EMF decoys that duplicate the ship’s EMF field for a short time to fool enemy sensors. EMFs are also disrupted by large “active” gas giants and stars. Many pirates, smugglers and military organizations place vital bases on the moons of gas giants or even in the upper atmosphere. These bases are virtually undetectable by EMF or gravity sensors, though they usually have to be heavily shielded against ambient radiation. Their weakness to ambient electrical fields and radiation means that sensitivity decreases based on range. Generally, they are as sensitive in regards to size as mass detectors.