The Free Trader, the standard Traveller small trading vessel, costs 37.098 Mcr (Megacredits). It is capable of a one-parsec (3.26 light-year) jump every three weeks with normal maintenance; the purchase cost amortized over a period of ten years means an effective cost of 71,000 Cr per journey. Other costs are:

Amortized ship cost	71,000Cr
Fuel, 20 tons at 500Cr/ton	10,000Cr
Maintenance, .1% ship cost/jump	37,000Cr
Total crew salaries/month	19,000Cr
Total cost per jump	137,000Cr

The cargo capacity of a Free Trader is 82 tons, so the cost of transporting 1 kg a distance of one parsec is about 1 2/3 credits. For comparison, a shotgun costs 160 Cr. This implies that, relative to other costs prevailing in the Imperium, the cost of interstellar transportation is relatively low, and a high level of interstellar trade is to be expected.

However, there is a major flaw in the Traveller ship system which Marc Miller apparently does not realize and the implications of which are not reflected in other aspects of the game. The smallest power plant that can be mounted on a spaceship is an A-rating plant. An A-plant consumes 20 tons of hydrogen in the course of a standard one-week interstellar jump. Now, starships do not in Traveller carry liquid oxygen, so it is clear that the hydrogen is not being burned to create energy. Instead, the power plant must be operating as a fusion device. Further, Miller does not permit ships to separate out the deuterium (heavy hydrogen, the easiest atom to fuse) and use only that to generate power. If he did, ships could carry vastly less fuel and would thus have much more space available for cargo. So the energy must be created by proton-proton fusion of raw hydrogen, tons of which are consumed each week -- the same fusion reaction which produces most of the sun's energy. (Actually, considering the energetics of proton-proton reactions, Imperial technology must be extremely advanced, since even at temperatures of millions of degrees, proton-proton fusion occurs very rarely. The Imperium must have some mechanism for catalyzing such reactions, something beyond the slightest glimmer of our comprehension at the moment.)

In proton-proton fusion, through a series of three reactions, four protons fuse to produce a single helium atom plus about 25Mev (million electron-volts), plus some stray gamma rays, neutrinos, and positrons. H¹ weights 1.008 g/mole, so 1 kilogram contains about 992 moles of hydrogen, or 5.97 x 10²⁶ atoms. Fusing these atoms produces 3.73 x 10²⁷ Mev. There are 1.60 x 10^-19 J/ev, so this is about equivalent to 5.97 x 10¹⁴ Joules, or about 19 MW-years. So there are about 19 MW-years of energy per kilogram of hydrogen.

The smallest power plant which may be installed on a ship in Traveller is a standard "A" power plan. The A-plant can consume 20 tons of hydrogen over a period of a week, convert it to energy, and feed it to an "A" FTL drive. (This is how much energy is needed by the smallest FTL drive to make a jump of 1 parsec if installed in a 200 ton ship.) If we assume Miller is using metric tons (1 ton = 1,000 kg), an A power plant then can deliver 380,000 MW-years of energy over a period of one week. Over a year, it could deliver 19,800,000 MW-years. Thus, a single A power plant produces about 86 times as much energy in a year as all of the electrical generating plants in the United States. A single jump in Traveller uses about 160% of the energy the US produces in a single year.

A "Jump 1" in Traveller corresponds to a travel distance of one parsec, about 3 1/3 light-years. Let us be generous and say a ship can travel 5 light-years at Jump 1, consuming 380,000 MW-years in the process. A Free Trader carries 82 tons of cargo, so the cost in energy to transport a kilogram is 380,000 divided by 82,000, or roughly 4.6 MW-years. This is about 5,000 times as good as the Boardman anti-matter drive, so that there is no doubt that interstellar trade in the Traveller universe is a good deal cheaper than in an Einsteinian one.

It still takes 6.7 million KW-hours of energy to transport a kilogram, however. That is a lot of energy. Now it is true that energy is very cheap (in terms of Imperial credits) in Traveller -- it has to be, given the cost of owning and operation an "A" power plant -- but the cheapness of energy means that other manufactured goods must be very cheap. So there still will be few goods worth trading in Traveller. What goods will be worth trading is debatable, since it is very difficult to estimate costs of production. However, certainly trade in bulk goods like metal ores, pig iron, or grains can be ruled out. The Traveller trading system does make it possible to make a profit trading such goods, but that is a peculiarity of the system. I think we can say with some assurance that in Traveller the primary items of trade will be 1.) luxuries, 2.) extremely rare resources such as superheavy metals and -- possibly -- radioactives, and 3.) high-tech goods to be sold on planets where they cannot easily be produced locally.