MasterGwydion
Emperor Mongoose
I seem to remember back in the FFS days that other hull types were also affected by atmosphere. Am I remembering wrong?
Starship Operator's Manual - Others for CT?
- Thread starter Longboat
- Start date
Condottiere
Emperor Mongoose
Atmospheric turbulence, reactionary rockets, and heat shields.
However, gravitational based manoeuvre drives resolves that, mostly, currently
MasterGwydion
Emperor Mongoose
What are the numbers on the table? First row seems to be radius in hundreds of kilometers. M is Mass as a ratio of mass versus the mass of the Earth? Gs are self-explanatory. Under the headings of 0.25 and the others, is that in kilometers or in hundreds of kilometers?
Sigtrygg
Emperor Mongoose
Sorry I was going to post the explanation but had to do stuff:
D is the planetary size digit from the UPP
R is its radius in millimeters (hundreds of kilometers)
M is its mass in Earth masses
G is gravity in Gs at various distances from its center (and G s is its surface gravity)
K is its density in Earth densities (most planets will have a density of 1 )
L is the distance from the planetary center at which gravity equals the value of G for a planet of mass M (when G is set equal to G s , L should equal R).
D is the planetary size digit from the UPP
R is its radius in millimeters (hundreds of kilometers)
M is its mass in Earth masses
G is gravity in Gs at various distances from its center (and G s is its surface gravity)
K is its density in Earth densities (most planets will have a density of 1 )
L is the distance from the planetary center at which gravity equals the value of G for a planet of mass M (when G is set equal to G s , L should equal R).
Fluffy Bunny Feet
Cosmic Mongoose
Depending on variables such as atmosphere density along with g and streamlining you may be reaching in atmosphere velocities where you burn up without heat shielding. Offhand I don't know of any standard trading vessels that have heat shielding though I might have missed it. Your passengers might not like looking out the port at your red hot wings.Can you roll forward? Can you accelerate along the ground? If yes then you accelerate on a very long road until you achieve escape speed
CordwainerFish
Emperor Mongoose
Lean into it. Have the steward serve ghost
[1] Where I live, it is a felony to call capsicums 'peppers'. Spell 'chile' with more than one i and you're looking at life. More than one l, life without parole.
Sigtrygg
Emperor Mongoose
This is
Using classic UWP generation, which is largely intact through all editions of Traveller except maybe GURPS, worlds as large as size 5 can be airless. Default surface gravity of 0.45G. Extended world generation can easily tilt things in favour of negative mods to the atmosphere roll due to temperature.
Size 3 - Mercury or Ganymede sized bodies - are about 0.25G. That's appreciable gravity.
As a point with escape velocity - it's still the point at which, however long you took to achieve it, using whatever means (giant cannon shot, hypersonic scramjet with rocket assist, conventional rocket into orbit then deploying a solar sail etc) you are gone.
Once you have contragravity and reactionless thrusters, I think it's not really going to matter what the local surface gravity is, at least at planetary levels.
Canonically, a TL8 Air/Raft is able to float and achieve orbit, regardless of local surface gravity. It would be very strange indeed if starships did not also use that technology to assist with taking off, operating close to a Gas Giant and so forth. Naturally, the thrust plate, or reaction drive or whatever other M-Drive is used push the bird along is going to get the ship into orbit far quicker than an Air/Raft can manage, and that's reflected in the rules.
Once you have contragravity and reactionless thrusters, I think it's not really going to matter what the local surface gravity is, at least at planetary levels.
Canonically, a TL8 Air/Raft is able to float and achieve orbit, regardless of local surface gravity. It would be very strange indeed if starships did not also use that technology to assist with taking off, operating close to a Gas Giant and so forth. Naturally, the thrust plate, or reaction drive or whatever other M-Drive is used push the bird along is going to get the ship into orbit far quicker than an Air/Raft can manage, and that's reflected in the rules.
CordwainerFish
Emperor Mongoose
Definitely except GT, which used the GURPS Space world design chassis: clearly made in awareness of Book 6, but different enough not to rouse lawyers.
MasterGwydion
Emperor Mongoose
Spaceships use M-Drive. Doesn't the Air Raft use a G-Drive?
Condottiere
Emperor Mongoose
It's all gravity based, likely including the jump drive.
It's how it's expressed, that may differ.
It's how it's expressed, that may differ.
Sigtrygg
Emperor Mongoose
Canonically the Terrans discovered the principles of the jump drive while researching other stuff:
"The asteroid belt station became the key to the future quite by accident. Exploitation of the asteroids required economical and efficient drives that would enable large quantities of ore to be moved about. The lab produced the thrusters that were called for, but it also discovered the jump drive (in 2087); the zero-G environment of the asteroid belt was exactly what was required before the space-rending effects of jump drive could be even
seen."
"In 2052, it was an UNSCA lab on Luna which produced the first practical “grav modules,” offering Terrans control of gravity for the first time. A
UNSCA research station on Ceres also produced the first working reactionless thrusters in 2064."
"The UNSCA research station on Ceres had one more miracle to produce. It was at that station that Terrans first developed the jump drive,
which allowed for accessible interstellar travel, in 2088. At first, the prototype jump drive was extremely fuel hungry and limited in range. It was
used only within Sol system, as a fast means of reaching the outer planets and the cometary cloud."
"The asteroid belt station became the key to the future quite by accident. Exploitation of the asteroids required economical and efficient drives that would enable large quantities of ore to be moved about. The lab produced the thrusters that were called for, but it also discovered the jump drive (in 2087); the zero-G environment of the asteroid belt was exactly what was required before the space-rending effects of jump drive could be even
seen."
"In 2052, it was an UNSCA lab on Luna which produced the first practical “grav modules,” offering Terrans control of gravity for the first time. A
UNSCA research station on Ceres also produced the first working reactionless thrusters in 2064."
"The UNSCA research station on Ceres had one more miracle to produce. It was at that station that Terrans first developed the jump drive,
which allowed for accessible interstellar travel, in 2088. At first, the prototype jump drive was extremely fuel hungry and limited in range. It was
used only within Sol system, as a fast means of reaching the outer planets and the cometary cloud."
Condottiere
Emperor Mongoose
Pretty sure it's a gravitational based civilization.
collins355
Cosmic Mongoose
In CT Striker vehicle design rules, you need to provide min. 1G grav module to get your craft off the ground (more if a higher G world obviously) and any extra over the 1G provides you with thrust to move your vehicle about other than up/down.
So if I install grav modules giving 1.6G, I first subtract 1G from that and then the remaining 0.6G is looked up on a chart that gives the designer the speed of the craft.
So if I install grav modules giving 1.6G, I first subtract 1G from that and then the remaining 0.6G is looked up on a chart that gives the designer the speed of the craft.
Condottiere
Emperor Mongoose
That's the current formula.
You get a full gravitational point, you can go hypersonic, according to Vehicles.
What's intriguing, is everything in between.
You get a full gravitational point, you can go hypersonic, according to Vehicles.
What's intriguing, is everything in between.
We were talking about planetary masking in the appropriately titled Planetary Masking thread. We also discussed M-Drives and a ship with a M-1 drive escaping a Size 8+ world that has 1G of surface gravity.
I was happy to see that the new SOM actually discusses this. I've read about 4/5ths of the Gravitics chaper, and I need to start from the beginning and read that chapter again. The book draws a lot from the original SOM written for MT and published by DGP. This new SOM also adds new stuff.
T-Plates (Thruster Plates) are back and used just about exactly as shown in the original SOM. Discussion also covers mounting M-Drives internally to mask the glow of the thrust surface of the plate, but the problem remains of the heat that must be expelled from the inside M-Drive compartment if mounted that way.
I do think this is a great book.
As for ships with M-1 drives escaping the surface of an Size 8+ world, Lifters are used in concert with the Maneuver Drive. This is a departure from the original SOM that used a short-term "overdrive" for the thrust on the T-Plate.
Lifters are basically large deck plates, or gravity plates, that allow a ship to hover while the M-Drive pushes the ship when it moves. These were called Contra-gravity plates in TNE. They can be mounted just inside the hull.
There are Lifters and there are Pusher that act like Tractor Beams.
There's an excellent discussion in the book about how M-Drives push off of large gravity sources--a nearby planet, moon, or even the system's star. The M-Drive cannot be used in deep space where there is nothing to push against.
It's very interesting, and we should discuss what it is like for ships in the far outsystem, a long way from the system's star or any planet. There can be dead zones out there where ships can get lost.
This is not unlike an 16th century sailing vessel being becalmed and unable to move due to no wind.
I was happy to see that the new SOM actually discusses this. I've read about 4/5ths of the Gravitics chaper, and I need to start from the beginning and read that chapter again. The book draws a lot from the original SOM written for MT and published by DGP. This new SOM also adds new stuff.
T-Plates (Thruster Plates) are back and used just about exactly as shown in the original SOM. Discussion also covers mounting M-Drives internally to mask the glow of the thrust surface of the plate, but the problem remains of the heat that must be expelled from the inside M-Drive compartment if mounted that way.
I do think this is a great book.
As for ships with M-1 drives escaping the surface of an Size 8+ world, Lifters are used in concert with the Maneuver Drive. This is a departure from the original SOM that used a short-term "overdrive" for the thrust on the T-Plate.
Lifters are basically large deck plates, or gravity plates, that allow a ship to hover while the M-Drive pushes the ship when it moves. These were called Contra-gravity plates in TNE. They can be mounted just inside the hull.
There are Lifters and there are Pusher that act like Tractor Beams.
There's an excellent discussion in the book about how M-Drives push off of large gravity sources--a nearby planet, moon, or even the system's star. The M-Drive cannot be used in deep space where there is nothing to push against.
It's very interesting, and we should discuss what it is like for ships in the far outsystem, a long way from the system's star or any planet. There can be dead zones out there where ships can get lost.
This is not unlike an 16th century sailing vessel being becalmed and unable to move due to no wind.
