MISSIONS.DAT
contains counters and race info on the ongoing acts. At the start of the game (beginner level) research in your home zone and terror in a close by zone is initiated. After that each new month you will get two new missions and a terror mission (beginner level).
Struture of a mission entry
Each mission has 4 words. With 7 acts on 12 zones these are 672 bytes. E.g. infiltration(3) in Europe(4) would have the offset 3*8+4*(7*8)=0xF8.
offset meaning 0 ufo-counter on the ufos within the mission (FFFF, the mission is not active) 2 sub-ufo-counter used for some missions 4 time-counter, 30 minutes to next ufo 6 alien race of mission
Races are:
0 Sectoid 1 Snakeman 2 Ethereal 3 Muton 4 Celatid 5 Floater 6 Silacoid
Timetable of a mission
When a mission starts, the ufo-counter is set to 0 and the time-counter to some act-depending time. The time-count is reduced every 30 minutes. When 0, an ufo will appear, the ufo-counter (or the sub-counter on some mission) will be increased and a new random time-counter for the new ufo will be set.
Note on the timing
The randomization makes it difficult to generalize ufo appearances, but there seem to be some categories:
immediate 1h 0.5-2.5h a day 1d 20h-30h some days 3d 2d-5d a week 1w 5.5d-8.5d two weeks 2w 10d-18d longer 1m e.g.46 days
Research
A undisturbed research mission on beginner level would look like this:
ufo-c time-c ufo-type
0 2.5h s.Scout (i.e. after 2 1/2 hours a small Scout
arrives somewhere)
1 1w m.Scout (after another week a medium Scout
will arrive)
2 1w l.Scout (...)
3 3d l.Scout
Harvest
ufo-c time-c ufo-type 0 3d s.Scout 1 3d s.Scout 2 1w s.Scout 3 3d l.Scout 5 3d l.Scout 5 1w Harvester 6 3d Harvester 7 1d Battleship
Abduction
ufo-c time-c ufo-type 0 1w s.Scout 1 1w m.Scout 2 2w l.Scout 3 3d Abductor 3/1 3d Abductor 4 1h Battleship
Infiltration
ufo-c time-c ufo-type 0 2w s.Scout 1 2w m.Scout 2 2w m.Scout 3 2w l.Scout 4 3d l.Scout 5 1h Terrorship 6 1h Battleship 7 1h Supply 8 1h Battleship
after this, the mission does not end, but starts again with ufo 0 again.
Base
ufo-c time-c ufo-type 0 1w s.Scout 1 1w m.Scout 2 1w l.Scout 3 1h Supply 3/1 1h Supply 4 1h Battleship
if you shoot down the supplys the battleship will not come for several weeks and a retaliation mission is started.
Terror
ufo-c time-c ufo-type 0 2.5h m.Scout 1 1w l.Scout 2 1w Terrorship 3 1w Terrorship
If you shoot the first Terrorship, the second is going to come 2w later. If you shoot the second Terrorship, the terror-site will not happen.
Retaliation
ufo-c time-c ufo-type 0 ? s.Scout 1 ? Battleship
Using the information
You might find that may small scouts appear at 2:30 on the first of a month. This is due to a often found count of 5 with the first ufo on a new terror or research mission for the month.
To make use of this knownledge might be difficult. But say, if you see a supply ship at a location without an alien base at the end of the third week of a month, it might be on a base mission. Then you should expect a second supply ship and a battleship somewhere close. If it is on infiltration you might see two battleships. If you see a first havester/abdutor, watch out for a second within three days. With a hyprewave decoder you might have more use from the mission sketches.