MT Only: DGP Starship Operator's Manual Vol 1. Starship Operations

[Hyphen]

Thank you for the explanation which has cleared up the instruction a lot more than I've gotten on my own. I never have been involved with the actual playing of MT, so I have zero experience on UTP.

Sounds like you've got it now.

All I was going to chip in was that all you're really doing is rolling for the time duration early, rather than after you've finished. (The referee writes it down, and gets to modify it slightly with those 1D-1D rolls, just to keep you on your toes.) But you get to estimate if you can complete a task, especially if you don't have a lot of time available. If you know the task is going to take too long, at least then you can choose not to do it, but do something else instead.



As for time to orbit not taking streamlining into account: well, steamlining IS taken into account when determining a vessel's max speed in atmosphere. For example, a so-called Slow Boat is faster (2565 kph) than a standard Ship's Boat (1000 kph) because the Slow Boat has an Airframe config, while the SB is only Streamlined.

How does this help? Well, take a look at the calcs on p 61 ("Normal Space Page 1 of 3"). Earth low orbit is 160 km straight up; this gets lengthened to 960 km due to atmosphere. (It's a bit of a cheat, since what really lengthens the flight is the need to tip over and travel sideways in order to achieve a rotating orbit around the planet, but lets go with the rules as written.)

An air/raft travels at 120 kmh max; it will take 8 hours to achieve orbit (960/120). Amazingly enough this is EXACTLY how long it takes in the original Bk 2 rules! :-O (It's almost as though someone thought about all this! ;-) ;-) )

A ship's boat will achieve orbit in (960/1000=) 57.6 minutes.

But a "slow" boat will get there in (960/2565=) 22.5 minutes. :-D

BTW, a standard shuttle is as fast as a "slow" boat as well!

 

[estar]

Those articloes were written by people who hadn't considered:
LBB" ships that operate in an atmosphere have to be 'streamlined' which implies either a lifting body hull form or even wings going by the illustrated examples.

Unless you are are on a Size 8 world or larger with little to no atmosphere. In which case the only way to get off either one of two ways.

1) Something allows for a higher output for a long enough time to get to orbital height.
2) Or you have a really long runway and wheels and accelerate to orbital velocity in which case your apotheoses can be set to whatever height you need and you can circularize your orbit at the point.

At the altitude where air can no longer provide lift the ship is already high enough that the planet's gravity is no longer 1g.

The fall off due to distance isn't significant enough to make a difference. At 200 km it is still 9.225 m/s^2 which is .94 G for Earth.

 

[estar]

Here's the thread we did, pretty thorough look at the topic-

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=34502

That reminded me of the other way I could achieve orbit with a traveller style craft.

All Traveller ship TL 9 or beyond have grav plate. So it is reasonable to assume that all Traveller Ship starting at TL 9 are equipment with a contra-gravity lift generator. When activated it will nullify the local gravity vector.

So however you define your Maneuver drive the contra-gravity lifter will allow a 1G thrust craft to lift of any size planet.

I did this in Orbiter by creating a invisible thruster in code. I had it automatically point towards the local gravity vector regardless of the ship's orientation and emitted enough thrust to cancel it out. I was able to get into orbit with a .1 G drive. Took awhile but I was able to do it.

 

[snrdg082102]

Hello estar,

That reminded me of the other way I could achieve orbit with a traveller style craft.

All Traveller ship TL 9 or beyond have grav plate. So it is reasonable to assume that all Traveller Ship starting at TL 9 are equipment with a contra-gravity lift generator. When activated it will nullify the local gravity vector.

I was not able to find anything in MT about Contra-Gravity Lift Generators nullifying local gravity, however TNE FF&S Mk I Mod 0 (January 1994) p. 75 says approximately 99% of gravitational force. Then again 99% is close enough to nullifying local gravity not to really matter.;-)

So however you define your Maneuver drive the contra-gravity lifter will allow a 1G thrust craft to lift of any size planet.

I did this in Orbiter by creating a invisible thruster in code. I had it automatically point towards the local gravity vector regardless of the ship's orientation and emitted enough thrust to cancel it out. I was able to get into orbit with a .1 G drive. Took awhile but I was able to do it.

How much was charged for the snacks while getting into orbit?

 

[estar]

I was not able to find anything in MT about Contra-Gravity Lift Generators nullifying local gravity, however TNE FF&S Mk I Mod 0 (January 1994) p. 75 says approximately 99% of gravitational force. Then again 99% is close enough to nullifying local gravity not to really matter.;-)

No you wouldn't find it mentioned in CT or MT hence the DGP answer in the Starship Operators Guide. The default back in the day was to ignore it all-together.

Yeah 1% is more than sufficient.

So however you define your Maneuver drive the contra-gravity lifter will allow a 1G thrust craft to lift of any size planet.

Exactly

How much was charged for the snacks while getting into orbit?

Didn't need too, just used my handy ancient tech device called time accel

 

[Supplement Four]

Those articloes were written by people who hadn't considered:
LBB" ships that operate in an atmosphere have to be 'streamlined' which implies either a lifting body hull form or even wings going by the illustrated examples.

What about the Size 8+ worlds without atmo?

 

[aramis]

What about the Size 8+ worlds without atmo?

Not generatable under Bk2 ...
Atm = 2d6-7+Size, so Size 8 has minimum atm 3...

 

[mike wightman]

What about the Size 8+ worlds without atmo?

Such a world would have to be a referee fudge (as Aramis says the design sequence forbids them) - a 1g ship would be stuck on such a world.

 

[snrdg082102]

Hello all,

From the discussion and my oversight of not providing the exact information from the TML topic "1G ship vs. Size 8 world" posted by Christopher Sean Hilton on 27 Sept. 03:00 UTC we appear to be discussing a world with a gravity of 1G.

The information provide by Christopher does not provide the gravity field that "under normal circumstances a 1G ship can't take off from a size 8 or greater world."

The System Generation rules in CT Book 2 Starships, CT Book 6 Scouts, MT Referee's Manual, MT World Builder's Handbook, TNE Core Rule Book, and TNE World Tamer's Handbook calculate a world's gravity among other statistics.

Do all Size 8 or greater worlds have a gravity field of 1G?

 

[estar]

Not generatable under Bk2 ...
Atm = 2d6-7+Size, so Size 8 has minimum atm 3...

Not enough to provide usable lift for takeoff.

 

[mike wightman]

Not enough to provide usable lift for takeoff.

Actually it is, provided you have a very long runway and your landing wheels or skids can stand the take off velocity of 500kph

 

[kilemall]

Hello all,

From the discussion and my oversight of not providing the exact information from the TML topic "1G ship vs. Size 8 world" posted by Christopher Sean Hilton on 27 Sept. 03:00 UTC we appear to be discussing a world with a gravity of 1G.

The information provide by Christopher does not provide the gravity field that "under normal circumstances a 1G ship can't take off from a size 8 or greater world."

The System Generation rules in CT Book 2 Starships, CT Book 6 Scouts, MT Referee's Manual, MT World Builder's Handbook, TNE Core Rule Book, and TNE World Tamer's Handbook calculate a world's gravity among other statistics.

Do all Size 8 or greater worlds have a gravity field of 1G?

Depends if you want to introduce differing densities due to composition, and what difference those make when compared to just the size of the planet in the first place.

 

[snrdg082102]

Hello kilemall,

Depends if you want to introduce differing densities due to composition, and what difference those make when compared to just the size of the planet in the first place.

Would I be on the right track by saying:
The current discussion is based on the assumption that a "1G ship vs. Size 8 world" or greater is not capable of lifting off if the world's 1g or greater on its own.

 

[kilemall]

Hello kilemall,



Would I be on the right track by saying:
The current discussion is based on the assumption that a "1G ship vs. Size 8 world" or greater is not capable of lifting off if the world's 1g or greater on its own.

Sure that's what we are talking about, and the SOM answer to that, and other people's answers as well.

The answer depends on what ruleset you want to use, what extra embellishments or factors you want to include, and I would hope a primary universe building architecture to frame the sort of stories you want to help your players make.

 

[snrdg082102]

Hello kilemall,

Sure that's what we are talking about, and the SOM answer to that, and other people's answers as well.

The answer depends on what ruleset you want to use, what extra embellishments or factors you want to include, and I would hope a primary universe building architecture to frame the sort of stories you want to help your players make.

I lost power for about three hours so thank you for the reply and the nod I'm on the right track.

 

[Carlobrand]

If I understand MT correctly, a standard atmosphere drops to the equivalent of "thin" (0.43 to 0.70 atmospheres) at between 3000 and 6800 meters, assuming an earthlike atmosphere, and to "very thin" (0.1 to 0.42 atmospheres) above 6800 meters feet. Top atmospheric speed increases 50% in thin atmosphere, and atmosphere does not limit speed in very thin atmosphere. Ergo, R.A.W., a ship only needs to get to 6800 meters altitude - or whatever the local boundary equivalent is - before atmosphere stops being an issue. So, top speed is only a consideration for the first few minutes of flight.

If you wanted, you could level a mountain top, build a landing pad there, and then ferry stuff down from there to let ships and GTO craft fly without atmospheric restrictions. Might help if you were needing to ground some unstreamlined box-ship for repairs.

 

[snrdg082102]

Hello Carlobrand,

If I understand MT correctly, a standard atmosphere drops to the equivalent of "thin" (0.43 to 0.70 atmospheres) at between 3000 and 6800 meters, assuming an earthlike atmosphere, and to "very thin" (0.1 to 0.42 atmospheres) above 6800 meters feet. Top atmospheric speed increases 50% in thin atmosphere, and atmosphere does not limit speed in very thin atmosphere. Ergo, R.A.W., a ship only needs to get to 6800 meters altitude - or whatever the local boundary equivalent is - before atmosphere stops being an issue. So, top speed is only a consideration for the first few minutes of flight.

If you wanted, you could level a mountain top, build a landing pad there, and then ferry stuff down from there to let ships and GTO craft fly without atmospheric restrictions. Might help if you were needing to ground some unstreamlined box-ship for repairs.

Thank you once again for your assistance to my questions here and the other Traveller pages. From the points you made I think you are on to how the SOM take-off maneuver works.

 

[kilemall]

If I understand MT correctly, a standard atmosphere drops to the equivalent of "thin" (0.43 to 0.70 atmospheres) at between 3000 and 6800 meters, assuming an earthlike atmosphere, and to "very thin" (0.1 to 0.42 atmospheres) above 6800 meters feet. Top atmospheric speed increases 50% in thin atmosphere, and atmosphere does not limit speed in very thin atmosphere. Ergo, R.A.W., a ship only needs to get to 6800 meters altitude - or whatever the local boundary equivalent is - before atmosphere stops being an issue. So, top speed is only a consideration for the first few minutes of flight.

If you wanted, you could level a mountain top, build a landing pad there, and then ferry stuff down from there to let ships and GTO craft fly without atmospheric restrictions. Might help if you were needing to ground some unstreamlined box-ship for repairs.

Or, build Earthport.

 

[snrdg082102]

Hello kilemall,

Nice illustrations and suggestion. An alternate would be the type of port used in 2300 AD/Traveller 2300 AD. which I believe has an adventure referencing the structure as a beanstalk.

 

[khadaji2002]

Beanstalks are one way around the issue, if YTU has this issue. IMTU the grav drives cancel out the effect of 1G so the ship merely needs a functioning maneuver drive to reach space. Another way around the issue would be to have far more worlds with High Ports. Space station in orbit around the planet with plenty of high-speed cutters able to carry ~30 dT of cargo each way. Yet a third option would be a moon base (if the world in question has a low-gravity moon) that has a mass driver system with the main planet.