Not everything is immediately visible to the sensors of the ship, even if they are close by. Scanning works on three principles, these are range of detection, scanning power and the profile of the object being scanned.

Range of Sensors
The first principle, Range of sensors is a fairly simple concept. Space is large, so it is the case that the ship actively scanning may not even come within range of an object in the first place. The larger the volume of space, the lower the chances of happening upon an object. When moving around a system from one quadrant to another, the chance of coming within sensor range of all objects in the orbital quadrant is roughly proportional to the orbital ring. Further, only the location moved into is checked, i.e. moving from Alpha 10 to Beta 10 will give a 10% chance of happening to get within sensor range of each object present within orbital quadrant Beta 10.

When moving across a system, from one orbital to the next (inwards or outwards) as a much smaller area is crossed, so the chance of happening to get within range of an object is roughly equal to the square of the orbital being scanned. Again it is the orbital being moved into which is scanned, i.e. moving from Alpha 9 to Alpha 10 gives a 1% chance of happening to get within sensor range of every object present within Alpha 10. Thus, it is much more effective when patrolling a system, if ships follow circular paths around the system.

In summary:
The chances of passing something when you move along a quadrant (e.g. from alpha 10 to beta 10) is (100/Ring)%
The chances of passing something when you move from ring to ring (e.g. from alpha 10 to alpha 9) is (100/Ring^2)%

Sensor Rating
The total output of the sensors of the ship produces a value called the sensor power. This is based on the total output of the sensors installed on the ship. No ship can have more that 10000 sensor output before officer skills. Increasing sensor numbers gives diminishing returns, so the sensor power of 20 sensors is not double the sensor power of 10 sensors. The conversion of output to power is then translated into a value called the sensor rating and is measured as a percentage. This is the chance of detecting an object with a sensor profile of 0%. Even a single sensor will give a positive sensor power resulting in a sensor rating greater than 0%. It is possible to achieve sensor ratings greater than 100%.

Sensor Profile
Every object, including ships, starbases, worlds and ground parties have a sensor profile. This can be a large negative to a large positive. If an object cannot normally be missed it will have a sensor profile greater than 100%.

Sensor profile is largely determined by surface area. The lighter hull ships are designed to have maximum volume for cargo. As such they have large surface areas when compared to ships that are built from the same number of hulls, but incorporating a heavier hulltype.

The table below gives an indication of the basic sensor profile of a 50 hull ship for varying hulltypes. Under normal circumstances, an xlight hulled ship is easily spotted, even at this small size.

Hull Type	Scanner Profile for a 50 hull ship
Heavy	25.6%
Normal	54.5%
Light	80.8%
Xtra Light	105.4%

As increasing the number of sensors installed in a ship will increase the sensor power of the ship, so too are there ways of decreasing the sensor profile of a ship.

Korondite Plates
As detailed in the combat and ship design sections plates can be layered onto a ship during construction. Certain types of plates counter scanners. These effectively reduce the sensor profile of the ship. As the number of plates that can be fitted to a ship is proportional to the hull type, heavy hull ships can utilise the most plates. The table indicates the results of using standard korondite plates for each hull type.

Hull Type	50 Hulls	100 Hulls	150 Hulls
Heavy	-43.5%	-10.3%	22.7%
Normal	12.0%	77.8%	133.0%
Light	68.4%	167.3%	250.3%
Xtra Light	98.4%	214.9%	312.6%

This means that a ship that gets within sensor range of a heavy hull ship (50 hulls) needs a sensor power of at least 44% in order to have even a basic chance of detecting it. There are even more advanced versions of korondite plates that will reduce the sensor profile of the ship even further.

Optical Depth and Planetary Factors
Celestial bodies with atmospheres will have an optical depth. This value will negatively effect the sensor power of a position scanning through the atmosphere.
Positions landed on a planet may also have their sensor profile reduced on account of the terrain they are in. Craters and mountains for example reduce their profile more significantly than flat and crust.

Location Modifiers
Certain regions of space and especially nebulas naturally reduce the profile of a position located within the affected region of space. Hints of these natural phenomena may be picked up by a system message such as those associated with the Arridian Spur:
"This is one of the systems that are collectively known as the Arridian Spur. They comprise at least 26 systems, though it is thought that more exist. The stars are close to a blue giant cluster that bathes most of the stars in radiation which hampers both sensors and jumping. This makes it a choice bolt hole for pirates and those that want to disappear."
Location modifiers can in theory be applied virtually anywhere including individual planetary sectors and even to specific affiliations (handy for mustering rebels in an urban sector on an occupied world).

Scan Location
The scan location order is given a number of tus and it works out how many times your position can pass by the section of space it is in based on its speed. So if this is a quadrant, the ISR speed of the ship determines how many passes you can do in an area. If you do pass into sensor range of the object a scan at the positions sensor rating is performed. If your sensor are not powerful enough to detect the object when you pass it then it will never be detected.

e.g. An ISR 3 ship in ring 10 taking 90 TUS.
It can traverse the quad in Ring x 3 = 30 tus. Therefore you can scan the quadrant 3 times in 90 Tus.
Each time the chance to pass close enough to scan an object is (100/Ring)%=10%. So the order attempts 3 passes of the location with only a 10% chance that you will be close enough to the object to have an effective scan. So roughly you have a 27% ((1-0.9^3)*100%) chance of passing a target object once or more.

Related to scanning and detection is the ability to cloak. All cloaking devices are advanced technologies, but as they are not uncommon their use is described here.

Cloaking devices make the ship completely undetectable irrespective of the sensor power of the scanning position. They also effectively make the cloaking position blind while cloaked, i.e. the cloaking position cannot scan.

All cloaking devices can operate for a limited amount of time. After this, the position has become charged with exotic particles. These do not interfere with the normal running of the position but are easily detected, which means that the position cannot be cloaked again until the charge dissipates. This normally requires 300TU’s of activity to pass since the last activation.

Example: If a ship uses its cloak as its last action on a turn, the manifest will state that it is ready in 300TU's. If the ship performs 50TU's worth of actions on the next day, the manifest will state that it will be ready in 250TU's. If however only an update is requested and no actions are carried out, it will still state that it ready in 300TU's. If the ship continues to do nothing, this number will only begin to fall after the ship has accumulated 300TU's worth of available TU's. After this period the ready time will fall at 60TU's per further day of inactivity.

All cloaking devices work on an optimum surface area that can be cloaked. In ships, this equates to total installation space (quantity of hulls multiplied by internal capacity). If the surface area of the ship attempting to cloak is greater than this value, the cloak will not work.

Ships are capable of blockading celestial bodies from the orbital quadrant. A blockade increases the chance of scanning positions entering and leaving the orbit of the celestial body being blockaded as though the blockading position was in orbit.
It is possible to move directly between moons and their parents in order to avoid blockades.