Class

Race - Class - Profession - Faction
Explorer	Tradesman	Warrior

Overview

Character Classes define a role and general set of abilities within Earth and Beyond.

The three classes available to each of the three races are:

Explorer

The only class who get the Prospect skill, therefore they are the only class who can:

gather raw resources from Prospecting Nodes by Prospecting
find Ancient Artifacts
refine raw resources into refined ones

Device specialists: more and higher level devices
Explorer-exclusive content such as the Mars construction site and the mission Fashionin' a Ring
Unique skills such as Create Wormhole (JE), Nullfactor Field (TS), and Call Forward (PS)
Scan, Navigate, and Jumpstart skills

Tradesman

Trade specialists, large 40 slot cargo holds at max hull upgrade
Negotiate skills
Broadest set of Build skills, with exclusive access to the Build Components skill
Healer role, only class with the Recharge Shields (all) and Hull Patch (TT and PP only) skills
Exclusive access to the best Psionic and Energy debuffing devices

Warrior

Weapons specialists:

More weapon slots
Access to a wider range of weapons (Warriors of all races have access to Beams, Missiles, and Projectiles)
Build Weapons skills

Combat skills such as Psionic Shield (JD), Rally (TE), and Combat Trance (PW)
Critical Targeting and Repair Equipment skills
Access to the broadest range of activated Turbo ship equipment

Class vs. Profession Ambiguity

There is significant ambiguity within the community on the definitions and meanings of "class" and "profession".
This is largely due to the fact that the game makes little to no reference to class at all which was more than likely a strategy employed due to three of the envisaged professions being omitted at the launch of the original Live version of Earth & Beyond. By referring instead to simply a combined concept of race+class, the game's developers were able to subtly avoid the issue that all three classes (Warrior/Trader/Explorer) were originally planned to be available for each race, which would have led to the game feeling incomplete at launch.
In-game, the terms "class" and "profession" are informally, interchangeably and ambiguously used; but on the wiki we've standardized on the following terminology:
Race — refers to Jenquai, Terran, and Progen,
Class — refers to Explorer, Tradesman, and Warrior, and
Profession — refers to combinations of the above two categories, viz. Jenquai Explorer, Jenquai Seeker, Jenquai Defender, Terran Scout, Terran Tradesman, Terran Enforcer, Progen Sentinel, Progen Privateer, and Progen Warrior.
This standardization is due to this usage largely being followed on the wiki already, as well as in the in-game character creation process, which at least makes it clear that there are nine professions, not three.
During character creation it says "Choose Profession" at the bottom, and the arrows move you through the nine professions. The Character and Starship Creator is even more explicit on this fact when Megan says right off the bat:

"All right, let's make a character! First you'll need to select a profession. There are six[nine] available and you can learn about each by clicking their names at the top of the screen."

On the other hand, when you select the Sentinel during character creation Megan says at one point (after to referring to it as a profession multiple times):

"A unique combination for a unique class."

So even here there is some ambiguity. However, it is clear that the most common interpretation is the one we're following for the wiki. That said, you should expect people to continue to use these terms interchangeably and ambiguously and they aren't wrong, it is ambiguous, but we're following the above guidelines on the wiki for consistency, so please do the same when contributing to the wiki.

There is still some (minor) debate regarding using the strict Race + Class names vs. the Official Profession names, and perhaps even more debate over the combination of Race + Profession and the resulting acronyms which are most commonly used, especially considering that the character creation shows:

Profession

Race + Class

But here we're leaning toward the Sunset Live interpretation which is the most commonly used in-game, on the forums, and on the wiki, i.e.

Profession	Abbreviation	Race	Class
Jenquai Explorer	JE	Jenquai	Explorer
Jenquai Seeker	JS	Jenquai	Tradesman
Jenquai Defender	JD	Jenquai	Warrior
Terran Scout	TS	Terran	Explorer
Terran Tradesman	TT	Terran	Tradesman
Terran Enforcer	TE	Terran	Warrior
Progen Sentinel	PS	Progen	Explorer
Progen Privateer	PP	Progen	Tradesman
Progen Warrior	PW	Progen	Warrior