Tachyona

Tachyona is the fastest orbiting world in the co-operative. It orbits so quickly, you can see its position change on the long-range chart of galactic sector 1.

Download link goes here.

From https://www.reddit.com/r/Oolite/comments/1aq19y7/comment/ks1x0gd/?context=3

Have a look at Arusqudi and Teorge: I overwrote a few lines of planetinfo to make them the same planet, and postulated the existence of the star Arus, at the location indicated. A simple script alternately hiding the planet(s) gives it a twelve day orbit. It's a simple little trinket OXP... until... ask what happens if the player is on one of those planets when it gets hidden? Suddenly the little trinket becomes a mammoth undertaking.

"use strict"; 
this.name = "Tachyona"; 
this.version = "1.0"; 

/* ======================================================== 
	`REQUIRES ONLY ONE MISSION VARIABLE`
=========================================================== */ 

this.startUp = function () { 
"use strict"; 
if (missionVariables.Tachyona_day === null) { 
missionVariables.Tachyona_day = 0; 
this.dayChanged(); 
} 
delete this.startUp; 
} 

/* ======================================================== 
	`A COUNTER THAT UPDATES THE DAY`
Systems are: 0 211 (Teorge) 
             0  68 (Arusqudi) 
=========================================================== */ 

this.dayChanged = function () { 
"use strict"; 
missionVariables.Tachyona_day++; 
if (missionVariables.Tachyona_day > 12) { 
missionVariables.Tachyona_day = 1; 
} 

var tday = missionVariables.Tachyona_day; 

if (tday > 4) { 
System.infoForSystem(0, 211).setProperty(3, "concealment", "300"); 
System.infoForSystem(0, 68).setProperty(3, "concealment", "300"); 
this._isPlayerPresent(211); 
} 

if (tday > 7) { 
System.infoForSystem(0, 211).setProperty(3, "concealment", "300"); 
System.infoForSystem(0, 68).setProperty(3, "concealment", "0"); 
} 

if (tday > 11) { 
System.infoForSystem(0, 211).setProperty(3, "concealment", "300"); 
System.infoForSystem(0, 68).setProperty(3, "concealment", "300"); 
this._isPlayerPresent(68); 
} 

if (tday < 5) { 
System.infoForSystem(0, 211).setProperty(3, "concealment", "0"); 
System.infoForSystem(0, 68).setProperty(3, "concealment", "300"); 
} 

mission.setInstructions("Tachyonan calendar: day " + tday + ".", this.name); 
}