Your work can use any of the game system rules and game terms found in the current edition Traveller books published by Mongoose Publishing.
You are allowed to use the Traveller setting as presented in the current Traveller edition books published by Mongoose Publishing as well as any Mongoose-published book covering the official Third Imperium setting (for example, Spinward Marches). This includes the names of all characters, races, and places and all gear, equipment and vessels; the capitalized names and original names of places, countries, creatures, geographic locations, historic events, items, ships, and organizations presented in those books.
To be clear, the setting of 2300AD is not open for use at this time.
Roleplaying game materials only.
No fiction except short vignettes in an rpg work
No software or comics
No art can be used from Mongoose publications (or any other Traveller publication). Art packs containing art that is allowed to be used in community content works may be made available by Mongoose to TAS creators.
There are many resources available here, most for free.
Logos and Trade Dress
You are encouraged to use the TAS logo on the cover of your title.
If the cover of your title shares the trade dress of official Traveller titles, then the TAS logo must appear on your cover prominently enough to be discernible even at cover thumbnail size (the size of cover images as seen while browsing DriveThruRPG).
You may not use any other Traveller or Mongoose logo.
You are encouraged (but not required) to use the template(s) found [here] when creating your work.
You can find more information on templates here.
The following text (placed within the Work, wherever the Work otherwise lists legal and copyright information):
This product was created under license. Traveller and its logo are trademarks of Far Future Enterprises. This work contains material that is copyright Mongoose Publishing and/or other authors. Such material is used with permission under the Community Content Agreement for The Travellers’ Aid Society.