Alien Missions (TFTD)
Alien Probe Mission
The Alien Probe Mission is used for correlating data about the seabed, the resources, shipping and aeroplane flight paths of an area. The Alien subs involved in these missions are not a major threat in themselves, but they indicate sites of activity that may flare at any time.
Alien Interdiction
The Aliens have a policy of policing areas they are interested in, sending out craft with the express purpose of securing an area before more intensive missions are begun. They will land at specific sites they intend to raid later to lock down the areas and prepare the way for the next level of activity.
Alien Resource Raid
The sinking of ships and the downing of aircraft are key elements of the Alien strategy. The acquisition of materials is one of the prime Alien activities and as such is allied to these overtly aggressive acts. The Aliens also raid areas of geo-thermal activity, mining sites and sites of antiquity for minerals and refined metals and other human produced items.
Alien Infiltration
This can result in official contact between Aliens and corporations or governments at the highest level. The climax of this activity is characterised by intense Alien Sub activity in the waters of the organisation concerned. The Aliens will attempt to sign an agreement with a government or organisation by offering knowledge of their superior technologies. This Alien activity represents a major threat to X-COM. If a corporation or government co-operates with the invaders then its funding ceases.
Alien Colony Expansion
These colonies are known to contain labs, cloning centres, surgical facilities for human and Alien experimentation. The presence of Alien colonies will generate more Alien activity without the presence of Alien Subs. In order to locate a colony an X-COM sub must patrol an area for a few hours to stand some chance of successful detection.
Alien Surface Attacks
When the Aliens need humans they terrorise a port, attack an island, or raid a ship. Civilians will be directly threatened, to fulfil the perverse breeding needs of the Aliens and their hideous experiments.
Floating Base Attack
If X-COM intercept subs are being particularly successful in sinking Alien craft then the Aliens may take some aggressive retaliatory action. This could result in a direct attack against an X-COM facility. However, the Aliens have to find an X-Com base in order to attack it, and provided Alien Subs are kept away then there should be little danger of an assault.
Colony Supply Missions
Once an Alien colony is constructed then it is re-supplied on a regular basis by a special supply ship. If one of these vessels is detected while touching down then it is certain that an Alien colony is nearby.