Atmospheric pressure effects on transition to and from orbit and other tidbits

[kilemall]

Look at ICBM re-entry profiles, then add ultra-tech handwavium.

Well yes but reasonable handwavium that has 'I can believe that' AND 'therein lies a game'.

 

[Condottiere]

If your gravitational motor based manoeuvre drive has a rating equal or greater to the local gravity, you can achieve, what we term as, a controlled descend.

I'm not sure how this quite works if you can only create lift less than local gravity, but with an aerodynamic hull, you should be able to make a soft landing.

If your ship cannot fulfill these criteria, results will get progressively worse.

 

[kilemall]

If your gravitational motor based manoeuvre drive has a rating equal or greater to the local gravity, you can achieve, what we term as, a controlled descend.

I'm not sure how this quite works if you can only create lift less than local gravity, but with an aerodynamic hull, you should be able to make a soft landing.

If your ship cannot fulfill these criteria, results will get progressively worse.

Which suggests that at least partial streamlined craft can land and take off- but very slowly, at air/raft speeds.

Landing at a distant location on a busy world or at a not busy starport or frontier world may work fine for those speeds, but a fully operational starport isn't going to have time to indulge ship operators in that approach.

 

[whartung]

Not sure OTH is gonna work that much better, other then it might help in limited opposition situations. Still going to pay some time getting help to your forces on target, and at least will need an FO with eyes on target and linking comms to render an accurate coordinate as opposed to direct target acquisition.

If you have the "eyes" to place a ballistic payload on to the target, you have them for an OTH delivery. At this point, you in theory already have orbital superiority to some degree. You don't need to laser the target, any seeking, guidable device can deliver to a pre-planned coordinate (i.e. ad hoc GPS). The point of the hypersonic deliver is, of course, to reduce engagement and reaction time when a Mach 5 vehicle suddenly appears a few hundred feet above the ground on the targets radar.

Kinetic penetrators would be cheap, that's where putting mass drivers onto starships for that could be a thing, still has to be built well enough to survive high speed reentry and maintain speed and relatively little drift to retain their kinetic speed and hit a target. Still means the penetrator can only go so fast but needs to go fast enough for one of several shots to hit.

While I guess you could call a kinetic penetrator launcher a "mass driver", it doesn't have to be a high velocity one. Just needs to get the payload kicked out the door of the carrier, from there it can adopt the carriers vector (to start the orbital decay), and then guide itself in. Structurally, it's, as they say, a "telephone pole made of tungsten". Just big, heavy (over 8,000kg), with some fins and a basic "GPS" guidance package. Even after normal atmospheric drag, they're expected to be impacting at Mach 10, over 3000m/s, over 10 kilotons of power on impact. And no residual radiation!

 

[Spinward Flow]

Which suggests that at least partial streamlined craft can land and take off- but very slowly, at air/raft speeds.

Landing at a distant location on a busy world or at a not busy starport or frontier world may work fine for those speeds, but a fully operational starport isn't going to have time to indulge ship operators in that approach.

The way I would interpret it is that the ship can only land (safely) and takeoff (safely) from what amounts to "prepared infrastructure" of some sort. This could involve anything from use of paved runways (kilometers in length) to making water landings in a sheltered (presumably artificial) lagoon or lake of some sort from which the ship is towed to a drydock transfer system or a pier-side berthing arrangement, as well as magnetic catapult launching systems.

In other words, the facilities don't need to be exactly akin to a airport with tarmac and gate terminals, but it will need to be something that is designed to handle starships for both landings and takeoffs, rather than just being an austere "airstrip" that's either an unpaved road or a nice grassy field somewhere. Also, beyond a certain tonnage, the sheer amount of ground pressure transfer through the landing gear to support the mass/weight of the starship in the local gravity will often times require either prepared paved surfaces and/or fluid buoyancy on liquids to support the weight of the ship while "parked" with the gravitic fields of the maneuver drive powered down.

Note that making soft landings onto (or into) liquids can get very interesting on worlds with atmosphere type A+ with "fluid oceans" that are not water.

Perhaps the most infamous example of this kind of landing into liquid has to be Iserlohn Fortress in Legends of the Galactic Heroes ... where the surface of an artificial satellite 60km in diameter (displacing 60 trillion tons!) with a crew of 2 million and a civilian support staff of 3 million (who could be supported indefinitely) with berthing for 20,000 ships(!) used a highly reflective "hydro-metal" surface ocean (think liquid mercury, but not exactly) as a protection against energy weapons and kinetic bombardments. Weapon systems would "float to the surface" to engage attackers on the fortress, including the Thor's Hammer energy weapon (which we would classify as a particle accelerator spinal mount in Traveller terms, except big enough to perform "area of effect" line of sight beams to destroy hundreds of ships in its beam path). All of the habitable facilities were "internal" inside this liquid ocean on the surface that acted as nigh impenetrable "armor" for the entire base.

 

[kilemall]

Spinward Flow, all relative to starport facilities and handling, but I'm looking at the question as I understand it from the OP, how busyness or not from a starport would affect landing and takeoff times.

Whether the ship comes in wheels up on a runway or lands on a tailsitter gantry, to me the primary bottleneck is the aerospace over the facilities. The main port is going to be a busy place, when you factor in all that cargo/passenger interaction with an up port, and I would think the variables I laid out are the main ones to consider.

 

[kilemall]

If you have the "eyes" to place a ballistic payload on to the target, you have them for an OTH delivery. At this point, you in theory already have orbital superiority to some degree. You don't need to laser the target, any seeking, guidable device can deliver to a pre-planned coordinate (i.e. ad hoc GPS). The point of the hypersonic deliver is, of course, to reduce engagement and reaction time when a Mach 5 vehicle suddenly appears a few hundred feet above the ground on the targets radar.

While I guess you could call a kinetic penetrator launcher a "mass driver", it doesn't have to be a high velocity one. Just needs to get the payload kicked out the door of the carrier, from there it can adopt the carriers vector (to start the orbital decay), and then guide itself in. Structurally, it's, as they say, a "telephone pole made of tungsten". Just big, heavy (over 8,000kg), with some fins and a basic "GPS" guidance package. Even after normal atmospheric drag, they're expected to be impacting at Mach 10, over 3000m/s, over 10 kilotons of power on impact. And no residual radiation!

Still has to be slow enough to not burn up through the atmosphere. I would think that's largely a vee vs. material science thing with better atmo transit facilitating faster/further out/less reaction time on both ends.

 

[Spinward Flow]

Spinward Flow, all relative to starport facilities and handling, but I'm looking at the question as I understand it from the OP, how busyness or not from a starport would affect landing and takeoff times.

Whether the ship comes in wheels up on a runway or lands on a tailsitter gantry, to me the primary bottleneck is the aerospace over the facilities. The main port is going to be a busy place, when you factor in all that cargo/passenger interaction with an up port, and I would think the variables I laid out are the main ones to consider.

Ah, well ... from that standpoint there are examples of "overburdened" starports being downgraded to more accurately reflect traffic congestion of their facilities. Best example of this phenomenon that I can remember off the top of my head is Rethe / Regina / Spinward Marches where a type B starport facility has been downgraded all the way down to Type E(!) simply due to traffic congestion.