Downports and landing non streamlined ships.

[briansommers]

So I get highports but what exactly does a downport do?

Also, why can’t non streamlined ships not land on surface?
I mean all the video games allow it.

 

[Reisender]

So I get highports but what exactly does a downport do?

Also, why can’t non streamlined ships not land on surface?
I mean all the video games allow it.

A highport is usually some form of spacestation, most likely orbiting a planet. Not every system/planet has a highport. A downport is on the surface of a planet.
Most planets with a listed spaceport have some form of atmosphere. It is the density of the atmosphere that cause problems for all things entering it in form of friction/resistance and other weather phenomena. Streamlined ships are designed to deal with this. Other hull configuration support this partially or even not at all.
And I don't think that video games make a good reference. While Traveller is certainly not a true hard sci-fi game it still tries to keep some form of plausibilty.

 

[briansommers]

Ahhh…thanks.

 

[Condottiere]

Depends on whether you have a manoeuvre drive.

And then it's probably a dead slow descent into the atmosphere.

 

[Arkathan]

I restrict them to coming straight down on their M-Drives in clear, calm weather, slowly. Slow enough to even out the pilot penalty, so air raft speeds, if there is a port with a control tower where they are landing. Dispersed structures can't even try it.

 

[ottarrus]

In one word, 'shuttles'.
Most [but certainly not all] unstreamlined spacecraft carry a landing craft of one type or another. Most of the time, that landing craft has enough room to carry the standard 10- and 20-dton cargo containers.

Other than that, IF the unstreamlined craft is equipped with landing gear [and very few do...], it depends on two factors: how powerful a maneuver drive the ship has and how much atmosphere the planet has. After all, even a brick will 'fly' if you put enough force behind it.

But even if a ship has enough 'oomph' to get up and down on a world, every single unstreamlined ship has the handling characteristics of the aforementioned brick when it's in atmospheric flight. They have no lifting /maneuvering surfaces [wings, elevators, ailerons, rudders, etc.] to help maneuver the craft.... it's straight 'force minus gravity equals lift' type flying, Apollo 11-style.

And something else to consider: is the spacecraft insured? Any reasonable insurance company is going to include a 'within the spacecraft's Safe Performance Envelope' clause in their boilerplate. And may the Ghost of Cleon help you if your ship isn't paid for. Landing an unstreamlined ship on a world with shuttle service is absolutely NOT 'within the Safe Operating Envelope' according to the bean-counters of the universe.

 

[Reisender]

In one word, 'shuttles'.
Most [but certainly not all] unstreamlined spacecraft carry a landing craft of one type or another. Most of the time, that landing craft has enough room to carry the standard 10- and 20-dton cargo containers.

That is one of the roles small crafts fulllfill. Other roles would be the connection between a downport and a highport, if both are present, or between downports of different planets within a star system.
Though we do know that the use of 'shuttles' for landing operations greatly diminishes once some form of transporter technology is discovered/developed "Beam me up, Scotty!"

 

[ottarrus]

Sure, but matter transportation [a'la Star Trek] doesn't come along until TL 17-18.
Until then, you're stuck with Mr. Pinnance.

 

[Condottiere]

There is the the beanstalk space elevator.

 

[Arkathan]

Bean stalks are prime terrorist/combatant targets. Those things do a lot of damage when they slam their way around a planet a couple of times, depending on how high up the cut is made. (Ground level cut just launches the up port into deep space).

 

[Condottiere]

It probably comes down to economics, mainly railways and truck roads.

 

[Chumbly]

Also, a factor is how strong the internal structures of the ship are if the ship is a dispersed hull, if the ship was designed only operate in zero or weak gravity, the ship support structures might fail under gravity especially under high gravity worlds due to a strong unexpected force pulling
‘downward’, ie the ship might be designed to withstand foward (bow) acceleration, with reinforcement structural integrity for forward movement, but crumple completely if every component is subjected to ”downward’ stress unaccounted for in the design of the craft

 

[Condottiere]

I wouldn't try it with the space station, but there is an option to armour dispersed structure hulls.

 

[ottarrus]

IMTU, while there is a possibility of close structure unstreamlined ships landing on a world, a dispersed structure would be so rare as to be worth a news story.
To put that another way, it's possible to land an Type C Broadsword-class, but the Annic Nova is right out.
The only way I'd let that fly at my table would be under the following circumstances:
- The world in question would have be small enough to exert very low gravity, 0.5 G or less
- The world would have to have an atmo of Very Thin or less
- The ship would have to push 2G maneuver or better
- The ship would have to actually spend tonnage space installing landing gear.
In any other condition that ride to the planet's surface is a one way trip.

 

[Arkathan]

I wouldn't try it with the space station, but there is an option to armour dispersed structure hulls.

Irrelevant when taking an unstreamlined hull into any atmosphere.
DM -4 pilot check on entry, and every minute thereafter, with 1D damage on a failed check, ignoring armor.
To demonstrate the folly of trying to land in something that was never meant to, I'd add the effect of the roll to any damage received, just to ensure the players learned to never try that again... and any NPCs on board would be near mutiny trying to stop them from attempting atmospheric ops to start with, unless they were just as likely to die if they stayed in space.

 

[Arkathan]

So I get highports but what exactly does a downport do?

Also, why can’t non streamlined ships not land on surface?
I mean all the video games allow it.

Re-reading your post, unstreamlined ships generally are not pictured landing.
Partially streamlined ships are.
Partially streamlined includes spheres and boxes.
Unstreamlined are either dispersed structures or planetoids (soon to be meteorites)

 

[Condottiere]

Depends on how it's defined.

Star Trek Federation starships tend to look like dispersed structure, and Tee Five does limit maximum acceleration.

Close structure feels like a cop out, in order to keep that design aesthetic without penalizing performance.

 

[Reisender]

Depends on how it's defined.

Star Trek Federation starships tend to look like dispersed structure, and Tee Five does limit maximum acceleration.

Close structure feels like a cop out, in order to keep that design aesthetic without penalizing performance.

Not sure if we move this threat away from its original intent but it might be usefulll to have some visual examples.
Federation:
USS Enterprise(TOS, NG, DS9,Enterprise): Most likely a Dispersed Structure, though later versions become more compact.
USS Voyager: More compact than the Enterprise but might still be considered to be a Dispersed Structure. But I can see that some people might considere this Standard or a Closed Structure.
USS Defiant(DS9): I would consider this Streamlined.

Borg:
Borg Cube: Though not a Dispersed Structure in your typical sense, I would still consider this as one. Even if it were just for its size.
Borg Sphere: Sphere, of course

Klingon:
Bird of Prey: Either Standard, Streamlined or Closed Structure; tend towards Streamlined here. We saw one land on Earth and on Vulcan. Seems to handle quite well within atmospheres. And it is my favourite ship class in Star Trek.

Romulan:
Bird of Prey(TOS): Standard or Closed Structure, maybe even Streamlined.
Bird of Prey(NG; DS9): Difficult one, the design says Standard, Streamlined or Closed Structure, but its size says Dispersed Structure to me

It is not always easy to use a certain classification on something that was not designed with that classification in mind.

 

[Condottiere]

There is the hole in the middle.

 

[Reisender]

There is the hole in the middle.

Does this make it more or less "dispersed"?
The structure archs around that "hole" and we do know that archs can be very stable, at least in some directions.
I'm not an engineer that is able to calculate the structural integrity of things under the influence of gravity. But I do know that gravity claimed many man-made constructions if they were not structurally sound or their structure got compromised. So the question is, is that arch enough to withstand gravity?
In the end I do what probably most people do, I ask myself, do I picture a ship flying through an atmosphere and land on a planet, and how well does it do so. I can imagine the Romulan Bird of Prey flying through an atmosphere no problem, but I do not see it land anywhere, hence I would assign Dispersed Structure to it.