Sorry should have explained better:
- You can get Orange Schematics from Crew skill missions such as Underworld Trading, Treasure Hunting, Diplomacy, Investigation, and Slicing when the mission is returned with a "Critical success". This will be reflected in the statement when you crew member returns as well as the schematic in the items. "Critical Success" is a 'luck of the roll' and by that I mean it is random, I've found that you can increase your chance by using a crew member that has increased skill in that area (e.g. crew member has +5 Critical - Investigation, send him/her on Investigation missions) and has a decent amount of affection. Also you'll want to run the missions that state; "Bountiful" or "Rich" in returns as again this have the higher chance.
Ironic as it is I've also found that the crafting skill most suited to your player (e.g. Artifice / Synthweaving for say a Jedi), their crew skills don't correspond well to the gathering skills. On my BH with Armstech it took ages before I got a schematic, where my Commando with Armormech it seems every other mission I'm getting a schematic (albeit the same ones over and over).
Bottom line is - there is no easy way to get them from gathering missions nor a way to guarantee that you will. The only way to do that is buy it from the GTN.