Powering up the Type S (numbers included)

[asciitraveller]

Hi,
i've recently tried to figure out if a Type S Scout powering up on the Earth could be observed from various points in the solar system. Here's what i have come up with:

First we have to know how much Energy is radiated. We need some assumptions:
1. The fuel consists of hydrogen 1.
2. by a 'magic/gravitic' process of turning protons in neutrons, we manage to fuse the whole two dtons per two weeks to helium 4.
3. the approx. 7MeV gained per hydrogen atom are reduced by the energy consumption of the magic (2.), and another big part is used by the ship's drives, so our Scout radiates about 30% of the energy generated.

Considering this, we can calculate the power produced (P0) in Watts

P0 = (tons of fuel [kg])*(Energy gained from fusion reaction per hydrogen atom [J])*(Avogadros number)/(atomic mass of hydrogen [kg])/(duration of consumption )

and the percentage radiated.

Now we just have to calculate the power radiated to an area (here 1m²) at a certain distance by

P.recieved=P.radiated/(4*pi*[distance in m]²)

to get the following results:

Fuel Consuption per 2 Weeks: 2 tons 
Percentage radiated: 30%
Reactor Power: 1.116 TW
 
             distance   power recieved
                [km]      [W]
Merkur        9.20E+07   3.15E-12
Venus         4.20E+07   1.51E-11
Luna          3.70E+05   1.95E-07
Mars          7.80E+07   4.38E-12
Jupiter       6.28E+08   6.76E-14
Saturn        1.28E+09   1.63E-14
Uranus        2.72E+09   3.60E-15
Neptun        4.35E+09   1.41E-15
Pluto         5.76E+09   8.02E-16

I assumed perfect alignment of all planets along one axis.

Lets compare that with an everyday example:

Light bulb
Power Radiated: 40 W

distance   power recieved [W]
  1  m         3.18
  1 km         3.18E-6
 10  km         3.18E-8
 40  km         1.99E-9
100 km         3.18E-10

Of course, to compare the results, we have to assume identical temperatures of the bulb and the scout, so that the radiated spectrum will be similar. To calculate this stuff for bigger drives, just multiply with coresspondent fuel consumption (or ask me for the spread sheet).

One other thing: 1 Joule of microwave energy consists of about 10^22 Photons, so with present day photomultipliers we would have still enough of them to detect the ship from Pluto.

Conclusion:
A Type S Scout on the Moon is about as bright as a 40W light bulb, switched on about 5 km away.

 

[DFW]

Excellent work. Saving this post to my GM notes folder.

 

[asciitraveller]

Any idea how to convert this in passive sensor rules?

 

[DFW]

Any idea how to convert this in passive sensor rules?

Not really. The passive sensors in MGT are ~TL 6. But your radiated power figures show what I suspected as far as IR detection ranges for star ships.

 

[asciitraveller]

One nice thing:
Think about all the little 40 W bulbs rushing across the sky in a busy system. One not so nice thing: Think about a small Types S landing on the surface, an the intense light which it radiates (400 GW!) to overcome the gravitational pull of the planet. Every observer would be blinded, and the heat would cause excessive atmospheric turbulences and evaporation of fluids. This could be really bad for the outer hull of the ship.

Now the real nice thing:
To land safely, one has to power down to the reactor and use aerodynamics to overcome the pull of gravity. That's why the scout is built with a streamlined hull.


EDIT:
Emitting 400GW for 3 minutes equals the energy output of the Hhiroshima bomb. We don't want to do this next to a starport.
EDIT2:
Sorry, wrong numbers in the edit. Corrected.

 

[Ishmael]

Any idea how to convert this in passive sensor rules?

these links might give some ideas although they're from older editions...

http://webspace.webring.com/people/lc/ca_barnett/misc/senrules.htm
http://webspace.webring.com/people/lc/ca_barnett/misc/sci_sens.htm
http://webspace.webring.com/people/lc/ca_barnett/misc/sen_addn.htm

 

[andrew boulton]

1dt/week is a silly amount of fuel, though (unless you assume much of it is coolant), and most of the time you won't be running at 100%. Other editions give more sensible numbers.

 

[rust]

1dt/week is a silly amount of fuel ...

Yep, 1 dton per 100 years would be a lot more plausible. Fusing
1 dton of hydrogen per week would result in at least the crew
and probably the ship being vaporized by the reactor's waste
heat alone.

 

[asciitraveller]

Emitting 400GW for 3 minutes equals the energy output of the Hhiroshima bomb.

The flight from Earths surface to the 100d takes 260 minutes. :lol:

If one would just use the deuterium (natural abundance 0.015%) we would just have ~175 MW and could use the Hydrogen for cooling or powering the fuel cells of ground vehicles. So, the Scout one the Moon would be more similar to the light bulb in a distance of 200 km or a firefly (the bug, not the ship) 1 km away.

 

[Rikki Tikki Traveller]

From previous editions of Traveller, the Type A power Plant produces 500 MW (250 MW per EP, 2 EP).

These are rough numbers of course.

 

[GypsyComet]

From previous editions of Traveller, the Type A power Plant produces 500 MW (250 MW per EP, 2 EP).

These are rough numbers of course.

High Guard/Striker/MegaTraveller numbers, specifically, and rather high. These are the same rules that, because of that rough equivalent, cheerfully focused enough power through a single laser turret's miracle conduits to carbonize any gunner and melt out the entire turret, its hardpoint, and a bit of the surrounding ship. For each shot.

I prefer the TNE power scale, which, roughly, is about 1/20th of the CT/MT scale.

 

[DFW]

I prefer the TNE power scale, which, roughly, is about 1/20th of the CT/MT scale.

1/20th the power level of CT wouldn't move a ship at multiple G's.

 

[GypsyComet]

Since TNE used reaction drives, that wasn't a problem.

You can have the best of both, however, by formalizing what pre-Striker CT assumed: Most of your power goes out the back as thrust, whether by funny physics or not. The rest of the ship is pretty low power unless you mount the big guns.

Striker through MT assumed that even normal laser turrets were equal partners with the drives as far as power needs.

 

[DFW]

Since TNE used reaction drives, that wasn't a problem.

That's right. I forgot TNE dropped the TL by 8 levels.

 

[GypsyComet]

Given the Isp that TNE was giving that reaction mass, not really. The HEPlaR drive was still insanely efficient.

Yet another balancing point for Traveller starship design. Reaction mass meant you weren't going full out across a system, but instead revving up a bit at the beginning and coasting. The drives were still multi-G, so even with a lot of coasting a system was still pretty open.