Conservation of Energy in Traveller

Usually, the Traveller M-Drive violates conservation of energy. But what if it did not? And how could that be, given the energy consumptions (and the zero-reaction-mass assumption) from Traveller starships' maneuver drives?

If we simply assume that the Traveller maneuver drive has a way to anchor the ship to spacetime and thus magically allows the ship to use the whole universe as its reaction mass (much like we all use the planet Earth as our reaction mass when jumping), then you'll need only negligible power for accelerating the reaction mass, even though this reaction mass is 5*10^52 kg. How?

When starting, we "accelerate the universe" to a speed of less than 1 Planck length per second. For example, for accelerating a 100-ston-ship to 11 m/s, you'd have to accelerate the universe to 2.2*10^(-47) meters per second. (A Planck length would be 1.6*10^(-35) meters). This requires a total of
0,5*5*10^52 kg * [2.2*10^(-47)]^2=
1,21*10^(-41) Joules.
In other words, not an amount of energy worth mentioning. Really. :-)

Now, in order to reach a given speed, we will need energy according to the following formula:


[2*(Energy capacity of M-Drive in Watts)*(time)/(ship's mass in kg)]^(0.5)

In other words, in order to reach a given speed, you'd need a total number of seconds


[(speed)^2*(ships's mass in kg)/(2*energy capacity of M-Drive in watts)]

That means, for example, that a standard Hero Class Private Merchant (LMass 720 stons, with a 110 MW-M-drive) will need the following times to reach given speeds in m/s:


Speed (m/s)     Time required (s)       Time required (h)       Time required (d)
0               0                       0                       0
10              0,33                    0                       0
20              1,31                    0                       0
50              8,18                    0                       0
100             32,73                   0,01                    0
200             130,91                  0,04                    0
500             818,18                  0,23                    0,01
1,000           3,272,73                0,91                    0,04
2,000           13,090,91               3,64                    0,15
5,000           81,818,18               22,73                   0,95
10,000          327,272,73              90,91                   3,79
20,000          1,309,090,91            363,64                  15,15
50,000          8,181,818,18            2,272,73                94,7
100,000         32,727,272,73           9,090,91                378,79

The distance travelled will be 1/2*speed*(time to reach that speed), if I am not mistaken (which is perfectly possible).

So, our Hero class merchant would, for example, need about 200,000 seconds, 54 hours or 2.25 days to reach a habitable world's 100 diameter limit (which equals about 750 000 000 meters of distance). (An Indomitable class battleship (LMass 190 000 stons, and a 85200 MW-drive) would need 1.59 days.) That would still be tolerable for travel purposes - interplanetary travel, of course, would require a jump drive or lots of patience (1 AU distance would take the Hero Class 77 days...).

These number assume that you arrive at your destination with lots of builtup speed, which would be no problem for jump points, a bit more so for planetary destinations. The 1 AU number for stopping at the destination with the Hero class would be 96 days, and for the 100D limit it would be 2.8 days.

Of course, this would mean a lot more complications in play: Each m-drive energy-to-mass-ratio would have to have its own travel times chart. The combat system would have to be totally reworked, especially with respect to the scale. Also, realistica

On the other hand, the ramming problem would be solved quite conveniently.

However, since actual energy consumption would depend on the current speed in relation to when the ship's drive was activated first, the bookeeping required for this would be forbidding. So let's forget the whole idea. :-)