A Trace Atmosphere is a type of atmosphere with a pressure of less than 0.1 atmospheres, which requires the use of a vacc suit.
Trace Atmospheres requires a vacc suit. The atmosphere has a pressure of less than 0.1 atmospheres, which requires the use of a vacc suit.
Surface Pressure & Water Properties
An atmosphere rated as Trace has a mean surface pressure ranging from 0.001 atm to 0.09 atm.
History & Background (Dossier)
Airless Worlds: A great many worlds in Charted Space have an Atmosphere type of 0 (Vacuum) or 1 (Trace).
- Although a trace atmosphere denotes a thin veneer of gases around a world (such as Mercury), it is of such barely measurable pressures that it may as well be a vacuum. Animal and plant life is non-existent on an airless world, although exotic and incredibly rare examples of vacuum life might exist (...and certainly be worthy of an IISS Scout mission).
- Mainstream sophonts must resort to living in bubble cities, underground settlements and other artificial, sealed environments. It can be difficult for a scout to differentiate these vacuum habitats. Try to take note of distinctive features at these settlements such as interesting geographical locations: at the entrance to a huge mine, straddling a small meteorite crater, along the walls of a canyon, inside old lava tubes, in the caldera of an extinct volcano, inside a network of vast, natural caves ... and so on. 
References & Contributors (Sources)
- Marc Miller. Worlds and Adventures (Game Designers Workshop, 1977), 5.Marc Miller, Robert Eaglestone, Don McKinney. Worlds and Adventures (Far Future Enterprises, 2019), 5.
- J. Andrew Keith. Exotic Atmospheres (Game Designers Workshop, 1983), 1-16. (Special Supplement 2 from the periodical Journal of the Travellers' Aid Society 17)
- Marc Miller. Referee's Manual (Game Designers Workshop, 1987), 22.
- Joe Fugate, J. Andrew Keith, Gary L. Thomas. World Builder's Handbook (Digest Group Publications, 1989), 64-68.
- Terrance McInnes, Dave Nilsen. World Tamer's Handbook (Game Designers Workshop, 1994), 11-17.
- Jon F. Zeigler. First In (Steve Jackson Games, 1999), 70,72.
- Paul Drye, Loren Wiseman, Jon F. Zeigler. Interstellar Wars (Steve Jackson Games, 2006), 125-6.
- Citation Missing - Mongoose Traveller Main Rulebook
- Marc Miller. T5 Core Rules (Far Future Enterprises, 2013), 409.
- Paul Elliott. The Universal World Profile (Zozer Games, 2016), TBD.
- Traveller Wiki Editorial Team
- Author & Contributor: Lord (Marquis) and Master of Sophontology Maksim-Smelchak of the Ministry of Science