"Warning: Trespassers will be shot. Survivors will be shot again." - unknown
One of my minor frustrations with the Traveller sector generation process was the creation of Amber and Red Zone worlds. I loved that they were included in the process, but there was no way to determine why the planet had a restricted classification. I've created the table below to address the reason for and enforcement of planetary interdiction.
IMTU the reason for the restriction is usually, but not always, made public and can be determined by contacting the local TAS office, Imperial Navy public liaison, or checking with a trusted news source. Amber Zones are not usually interdicted, but Red Zones almost always are. Note that the official reason a planet has been interdicted is not always the real reason.
Travel Zone & Interdiction (A for Amber Zone, R for Red Zone)
A1 general chaos
A2 societal upheaval
A3 local xenophobia
A4 government coup
A6 oppressive government
A7 oppressive laws
A8 dangerous society
A9 minor war
R1 wildlife refuge
R2 protect developing society
R3 wealthy family's private reserve
R4 to protect valuable resources
R5 protect sensitive installation
R6 punishment of local government
R7 quarantine a disease
R8 trade embargo
R9 world war
RA global disaster
RB Ancient site
RC protect military base
RD military or arms embargo
RE known psionic community
Interdiction Classification and Enforcement
Class and Actions Taken
0: No travel restrictions, not interdicted
1: Automated satellite - Broadcasts restrictions, and collects transponder data of ships entering in range of system
2: Automated satellite - Will open fire on ships entering the restricted zone
3: Automated or manned satellite- Will open fire on ships entering the restricted zone
4: Interdiction Station (400 ton) - Will open fire on ships entering the restricted zone
5: Close Escort (300 ton)- Will intercept ships and escort them away or fire upon them if necessary
6: System Defense Boat (400 ton) - Will intercept ships and escort them away or fire upon them if necessary
The class and quantity of enforcement units goes up with the Navy's assessment, but there are usually 3 to 4 units per system.
An example of a Class 2 satellite is the InSat-12, shown below.
An example of a Class 3 satellite is the 300 ton Type SMU-4C/D from GW's IISS Ship Files.
An example of a Class 4 Interdiction Station can be found in Space Gamer magazine (#67).
An example of a Class 5 Close Escort can be found in Supplement 7 - Traders and Gunboats.
An example of a Class 6 System Defense Boat can be found in Supplement 7 - Traders and Gunboats.
For the purposes of this article, interdiction refers to the prohibition of access to a world from the outside. It does not inherently prevent anything leaving the planet. Interdiction differs from a blockade, which is intended to prohibit any ships from entering or exiting a world. The typical interdicted zone is a sphere of 100 planetary diameters, although this often varies, especially for smaller worlds. The Imperial Navy views penetrating the 100 diameter sphere as indicated clear intent of planetary interaction as it is the cut-off point for safe jumps.
Weapons Platforms and Spy Satellites
The design of an interdiction satellite is not too much different from the design of an orbital weapons platform, interdiction satellites just tend to announce their intentions first. Some satellites are fitted with a wide variety of sensors, so that the conditions on the planet may be monitored.
The InSat-12 Automated Interdiction Satellite
The InSat-12 is a twelve ton, Class 2 automated interdiction satellite used by the Imperial Navy. It is fairly standard for its class, which typically range from 10 to 40 dtons. This satellite is produced at TL14 and uses a L-Hyd fueled power plant. Older models and some produced at earlier tech levels still use a generator and solar collection panels for power. It produces 0.25 g, enough to allow for orbit corrections, but little else. It is armed with a double pulse laser turret and a multiple sensors.