Escape Velocity

[The Shaman]

Originally posted by Commander Drax:
That's one impressive bacterium, surviving in fuel tanks, I mean liquid hydrogen (very cold). . .

Liquid hydrogen in the fuel tanks is cycled through the power plant and drives as coolant, keeping the temperature high enough for the hypothermophilic Jovibacter to survive and reproduce.

(Cloud-top temps are about 70-80 kelvin, so Jovibacter is used to some chilly conditions, though admittedly not the 30-something kelvin at which liquid hydrogen is stored. Do you know of a Traveller source which describes the temperature and pressure inside a starship's fuel tanks?

)

 

[The Shaman]

Originally posted by Commander Drax:
That's one impressive bacterium, surviving in fuel tanks, I mean liquid hydrogen (very cold). . .

Liquid hydrogen in the fuel tanks is cycled through the power plant and drives as coolant, keeping the temperature high enough for the hypothermophilic Jovibacter to survive and reproduce.

(Cloud-top temps are about 70-80 kelvin, so Jovibacter is used to some chilly conditions, though admittedly not the 30-something kelvin at which liquid hydrogen is stored. Do you know of a Traveller source which describes the temperature and pressure inside a starship's fuel tanks?

)

 

[BlackBat242]

I deal with the "planetary G-rating vs MG G-rating" issue in this manner:

I feel that the gravity-based Maneuver Drive (has to be, since it uses so little fuel that it cannot be any form of reaction drive) can be compared to another lift system... the helicopter.

A helicopter has two lift ratings... IGE (In Ground Effect) and OGE (Out of Ground Effect).

When the helicopter is close to the ground, the downward "rotor wash" of moving air impacts on the ground, and has to then move outward to make way for the air that is following. This creats an area of very high-pressure air, which increases the effectiveness of the lift produced by the rotors.

When the helicopter is some distance above the ground, the "rotor wash" spreads out and dissipates before it can create that increased air pressure, and therefore the rotors have only their basic aerodynamic lift effect.


To relate this to a starship's MD, remember that gravity is the attraction of two masses for each other... and therefore "contra-grav", or "anti'grav", and (in my view MDs) modifies this "field" by reversing or varying its effects.

Also remember that gravitational attraction increases as objects get closer, and decreases with the square of the distance.

These two physical principles mean that the effectiveness of a grav-based MD would increase naturally, without any need to adjust power output, as the ship came closer to a physical object.

Therefore, a 1G MD would function as if it were a higher-rated drive while in close proximity to a large mass, but only in relation to that mass, not to general maneuverability.

I generally state that the limit on this is the G-rating of the drive or the G-rating of the mass, whichever is lower.

Therefore, a 1G MD has a maximum "NME" (Near Mass Effect) rating of 2G when near a 1G (or greater) planet... but if the "Near Mass" is only a .5G planet, then it is effectively a 1.5G MD for landing/take-off purposes... but it still maneuvers as a 1G drive in all other respects. If near a 2.5G planet, it is still only a 2G "NME" drive, and therefore could not take off or land, although it could make a controlled .5G crash "landing".

 

[BlackBat242]

I deal with the "planetary G-rating vs MG G-rating" issue in this manner:

I feel that the gravity-based Maneuver Drive (has to be, since it uses so little fuel that it cannot be any form of reaction drive) can be compared to another lift system... the helicopter.

A helicopter has two lift ratings... IGE (In Ground Effect) and OGE (Out of Ground Effect).

When the helicopter is close to the ground, the downward "rotor wash" of moving air impacts on the ground, and has to then move outward to make way for the air that is following. This creats an area of very high-pressure air, which increases the effectiveness of the lift produced by the rotors.

When the helicopter is some distance above the ground, the "rotor wash" spreads out and dissipates before it can create that increased air pressure, and therefore the rotors have only their basic aerodynamic lift effect.


To relate this to a starship's MD, remember that gravity is the attraction of two masses for each other... and therefore "contra-grav", or "anti'grav", and (in my view MDs) modifies this "field" by reversing or varying its effects.

Also remember that gravitational attraction increases as objects get closer, and decreases with the square of the distance.

These two physical principles mean that the effectiveness of a grav-based MD would increase naturally, without any need to adjust power output, as the ship came closer to a physical object.

Therefore, a 1G MD would function as if it were a higher-rated drive while in close proximity to a large mass, but only in relation to that mass, not to general maneuverability.

I generally state that the limit on this is the G-rating of the drive or the G-rating of the mass, whichever is lower.

Therefore, a 1G MD has a maximum "NME" (Near Mass Effect) rating of 2G when near a 1G (or greater) planet... but if the "Near Mass" is only a .5G planet, then it is effectively a 1.5G MD for landing/take-off purposes... but it still maneuvers as a 1G drive in all other respects. If near a 2.5G planet, it is still only a 2G "NME" drive, and therefore could not take off or land, although it could make a controlled .5G crash "landing".