Jazzyamx
10/11/20 02:03 AM
96.42.48.89
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No, I'm not talking about trying to 'land' one of these spacegoing behemoths or attempting to have one somehow take off from a gravity well--that'd be silly. I'm asking if you dismantled one in orbit and brought all the bits down to a planet surface and reassembled it, could the fully assembled starship stand up to 1G if you set it up like a skyscraper with the proper supports on the hull?
I'm thinking of something like a museum ship, an ancient Aquilla-Class permanently decommissioned and brought down to the surface where people can safely visit without the risk of the void of space outside.
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Richard
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ghostrider
10/11/20 12:15 PM
66.74.60.165
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I don't see why not. They do occasionally have to travel into a gravity well, those not that much gravity. They are, after all, metal frames.
It is also suggested that there are some forces from the jumps that could stress the frame.
I believe you know, it would have to be done in chunks, as not many ships could handle something a kilometer or more, long while trying to land with it. It may need extra things added to it, as you don't 'walk' anywhere in the ship. You grab some handles and propel yourself along. Hard to change levels without ladders or stairs. Granted, this could be a misconception on my part, so take it with a grain of salt.
With this in mind, you may have to install an elevator or two, as some people will NOT be able to climb ladders for long.
As a side note, you could always reinforce areas if they are a little more fragile then normal.
I would suggest replacing the jump drive with a fake model, as someone would try to activate it. I would think someone would dare someone else just to see if it would jump.
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Karagin
10/11/20 01:16 PM
70.118.172.64
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Warships have crash landed and most of the superstrutcure survived for centuries. So having a Jumpship "land" or end up on a planet via a bad jump is not impossible. Just not highly recommended.
Karagin
Given time and plenty of paper, a philosopher can prove anything.
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Cray
10/11/20 06:30 PM
71.47.151.234
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Quote:
No, I'm not talking about trying to 'land' one of these spacegoing behemoths or attempting to have one somehow take off from a gravity well--that'd be silly. I'm asking if you dismantled one in orbit and brought all the bits down to a planet surface and reassembled it, could the fully assembled starship stand up to 1G if you set it up like a skyscraper with the proper supports on the hull?
I'm thinking of something like a museum ship, an ancient Aquilla-Class permanently decommissioned and brought down to the surface where people can safely visit without the risk of the void of space outside.
Yes, with caveats.
The Structural Integrity of a ship tells you how much overthrust a ship can endure, and 2 thrust points equals 1G. Quite frequently, WarShips (and primitives like the Aquilla) can endure quite a few Gs of thrust. JumpShips, however, tend to be on the low end of things, particularly their Kearny-Fuchida Drive integrity.
The wisest thing to do would be to ditch the massive KF core (the germanium can be used for another core anyway) and bring the hull down in chunks as suggested. That both gets rid of the most fragile bit of the ship and most of the weight it'd have to carry on the ground.
Then, yes, you could stand it on tail as a monument.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Wick
10/11/20 09:03 PM
173.247.25.195
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I think you are right that it would have to be displayed vertically rather than horizontally or some kind of additional support would be needed. However, these things are built in space and operate solely in space, so their construction will be oriented around space travel, not planet surface display. Some of the frame may not stand up to Earth-like gravity even standing vertically. Apollo lunar landers come to mind, as I don't think their legs were designed to support to full weight of the craft at 1G, only at 1/6 G of the lunar surface. You need to be aware that by standing it on its tail the bottom is not just supporting its own weight against gravity, but the weight of the entire craft above it. I am skeptical jumpships are designed with this thought in mind. If the maximum thrust in space is 0.1 G, they aren't going to overbuild the frame enough to support ten times that stress. (A warship though would be built sturdy enough to support >1 G thrust so it should be able to stand up to Earth-like gravity.)
I am skeptical of the ability to remove the jump drive core though. The whole ship is built around it. I suppose if you're disassembling it and bringing it down to the surface in bits you could do it, but you'd need a new framework to rebuilt it around. This framework could supply a lot of additional structural support to withstand Earth-like gravity though.
If someone took that discarded drive core and built a new ship around it, it would constitute a bit of a Ship of Theseus puzzle over which of the two is the original.
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ghostrider
10/11/20 11:14 PM
66.74.60.165
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The lunar lander was built and tested in 1G of the earth. It can support the weight of everything on it. The base was made to allow the top of it, a stable platform to take off from. The moon surface was thought to be questionable if it could support a launch.
I would think that the structure would be able to maintain it's form when being set up, as the 1G would not be side pressure, or quick change of direction. This is granting that earthquakes and high winds are not a factor. Even with that, the ship does have to deal with the sails as well as any odd solar winds. Being hit by weapons fire tends to put odd pressure on the structure. They also get hit by meteors on occasion, as the Invader jump ship says the ship has weapons on board to shoot down meteors. I will grant that would be more likely to avoid holes in the sails, but they would be used to prevent ship impacts. Also, the armor suggests it has something for such a case.
The jump core would be an interesting question.
It is the core of the ship, but yet it does need to be maintained as well as removed and replaced from time to time. I would think it is more like an engine inside a vehicle, then being used as a frame for the same thing.
If you want to say it is structurally necessary, then when bringing it down, removing it, and adding in support structures to replace it, would be a good idea.
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Wick
10/12/20 12:55 PM
173.247.25.195
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They didn't test the landing of actual LMs on the Earth though. They used mockups which would have had reinforced legs. And probably weren't full of fuel either (which adds a significant amount of mass.) Looking at a photo of one I took at the Marshall SFC and a photo of the one at the Smithsonian I don't see any supports under the descent stage, so they appear to be standing on their legs, but no idea if the legs are original or replaced with reinforcements (the surface sensing probes are notably absent) and certainly neither is fueled or carrying a science package. The one at Houston is hung from overhead and isn't resting on the ground. And the only photo I can find of the one in Philadelphia is supported underneath. When the designers seriously questioned whether the weight of an additional fifth leg was worth or or not, then it seems likely the real landers would have been built specifically for moon gravity, not Earth in the interest of weight savings. I've only ever seen photos and videos of space-flown landers being hauled around by overhead crane, never set on their legs. Even during launch, the LM is resting on its decent stage in the fairing with legs folded up. Probably need a Grumman engineer to tell us one way or another. I can't find any conclusive evidence via Google search. In any case I was only using it as a 20th century example for problems a 31st century person might have supporting a jumpship in Earth-like Gravity. Whether original LMs legs can or can't support the weight in Earth gravity doesn't change the fact that there could be similar problems with jumpships (hydroponics pods, docking collar grapples, etc.) I mean, look at https://www.sarna.net/wiki/File:Invader_floorplants.jpg and tell me those outboard hydroponic pods aren't likely to fall off without some kind of external support.
I think the weapons on jumpships are meant to destroy large asteroids and scare off pirates. Smaller asteroids would be very difficult to track. And the standard jump points should be relatively devoid of such material so its generally only an issue when using non-standard jump points or during inter-system transit. Presumably the outer shell of jumpships (and dropships) are strong enough to resist micrometeorite impacts or self-seal in some way. What meteoroids do exist in the vicinity of jump points would cause perforations in an unfurled solar sail but the size of the sail is many magnitudes greater than the tiny holes small meteorites would make so I doubt it affects performance. Warships or more reckless operators (including pirates) might need to replace their sails periodically though. But I'd anticipate enemy fire is still a far greater threat to a sail than meteorite impacts. For every sail that has to be replaced due to meteorite damage there's probably a hundred that need to because of hostile action. (And in practical applications, hostile attackers wouldn't be trying to shoot holes in the sail, but rather to sever the lines connecting the sail to the jumpship. Again, the sail is gigantic compared to the size of holes weapons fire would make.)
Given some more thought in the subject, the canon existence of jumpships having their drives replaced with compact versions does prove your point about it being more like a car's engine than its frame. It therefore must be easier to remove and replace than I had thought when I wrote my previous post.
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Cray
10/12/20 08:59 PM
71.47.151.234
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I think you are right that it would have to be displayed vertically
The decks of non-aerodyne spacecraft are arranged "like flying skyscrapers" because their sense of "gravity" comes from the acceleration delivered by their stern-mounted engines. You could lay a WarShip or JumpShip horizontally on the ground but all the decks would be on their sides.
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However, these things are built in space and operate solely in space, so their construction will be oriented around space travel, not planet surface display. Some of the frame may not stand up to Earth-like gravity even standing vertically.
The Aquilla-class transport that the original poster was interested in has a structural integrity of 10, which means it can survive 5Gs indefinitely, no SI rolls required. It can handle 5Gs from its engines (which can only deliver 1G), 5Gs from a quick pivot during combat, or 5Gs of shock from a collision. Every deck, chair, ladder, and toilet in the Aquilla can handle 5 gravities without a roll for failure.
Conventional JumpShips are another matter. They all have SI 1, which means they can handle 0.5Gs. You could remove the KF core (see below for the feasibility) to drastically lower the weight and thus structural load, but every deck and fitting is only meant to handle 0.5Gs max.
There are other factors. As a creature of deep space, JumpShips and WarShips...
1. Take massive damage from even slow passage through the atmosphere per the atmospheric movement rules in AT2R and Total Warfare. They would need to be delivered to the ground in sections.
2. They have no landing gear, so would definitely need to be braced and held in place. Moreso, they are meant to handle 0.5 or 1G coming through their engine, not just sitting on its butt, so the scaffold or structure would have to work around the awkward shape of the ship.
3. While their interior is meant to handle oxygen- and humidity-loving humans, the exterior is unlikely to handle a terrestrial environment well and would be very vulnerable to corrosion (unlike multi-environment DropShips). The scaffold should probably include climate control.
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I am skeptical of the ability to remove the jump drive core though.
See Strategic Operations p. 130, sidebar "Repairing Stranded JumpShips." Given the frequency of KF core damage, JumpShips and WarShips are designed with the ability to remove and replace their KF cores. It is an onerous and expensive task that the Star League and earlier eras rarely considered worthwhile, but the JumpShip-starved Successor States were willing to do so.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Wick
10/12/20 10:26 PM
173.247.25.195
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3. While their interior is meant to handle oxygen- and humidity-loving humans, the exterior is unlikely to handle a terrestrial environment well and would be very vulnerable to corrosion (unlike multi-environment DropShips). The scaffold should probably include climate control.
I doubt the skin of the ship is in any major climate danger. All indications are that its some form of fairly thick metal alloy - ferroaluminum, steel, etc. meant to stand up to micrometeorite impacts. It may very well tarnish in color or even rust in an oxygen-nitrogen environment but it should take many years - decades at least, if not centuries - for rust to eat through the shell of the ship. Acid rain could accelerate the process slightly but not enough to change the order of magnitude unless the acidity was so extreme to be fatal to humans. The body of a car isn't strong enough to withstand such impacts but it can last decades outdoors before rust takes its toll and collapses the frame. A jumpship should do better. At least akin to aircraft (and if you've seen airplane graveyards full of WW2 bombers, those things look almost new from a distance decades after being retired from service.)
Any paint or exterior markings could definitely at risk though. Those on jumpships and warships would be applied in an anaerobic environment so oxygen or rain could easily fade or wash them away in short order. Even the "high" temperature of a planet's surface compared to deep space could be disastrous for external markings as they could potentially "boil off". If the intent is to display a solid silver-gray tower of steel that's one thing, but if its got symbology or lettering painted on it (as it appears most do from art and miniatures) and such markings need to be retained, then it either needs to be put under a roof or repainted with terrestrial paints.
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Another concern is whether any of the externally exposed components are subject to pressure. There may be valves or other components that would rupture under 1atm of pressure or simply not work as designed. I can't imagine any such component would ruin the display of the jumpship from afar but it could disable certain functionality onboard. For example, the waste disposal system might have valves or pumps only designed for low pressure situations, so I wouldn't advise visitors to use the toilet. (Not the least of which is that waste would come out the head/crewquarters of the craft, not the engine/bottom. Look out below.)
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ghostrider
10/13/20 01:00 AM
66.74.60.165
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Well the jump ship would have to handle freezing water as well as oxidation as any leaks would cause such issues. This is not even going over what might be encountered in space. Then combat itself would cause more issues, even without having armor pierced. The 'toxic' exhaust from missiles would be one of those factors. This is not saying anything about being in the exhaust plume of fusion engines, such as a dropship coming in hot, or even undocking for a quick fight.
And this would also mean the docking collar as well as any mounts, including the jumpship, would have to be able to handle some bumps from poor pilots, malfunctioning equipment, or just haste to get out of a situation.
Also, some jumpship facilities are pressurized, so they would be subjected to the normal issues of an atmosphere, though only an explosive breach would come close to a wind storm.
There are a few things that might be needed with the paint and such. If it is the same stuff that dropships use, then atmosphere isn't going to be a major issue, as dropships that land, deal with those issues all of the time.
The pressure for components may not be an issue, as the game hints most, if not all, jumpship parts are manufactured on planets and sent up to the ship yards during the time that most space factories were off line.
But the toilet is a good example of things having to be fitted for normal gravity. I would think more then that would need refits. Imagine if you tried to put a restaurant on it. You don't want hot oil cascading down the side of the ship. Not that it would be hot when it hit bottom, but the mess left would need to be cleaned up. I don't think normal window washers would be inclined to clean it up.
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Cray
10/13/20 07:56 PM
71.47.151.234
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Quote:
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3. While their interior is meant to handle oxygen- and humidity-loving humans, the exterior is unlikely to handle a terrestrial environment well and would be very vulnerable to corrosion (unlike multi-environment DropShips). The scaffold should probably include climate control.
I doubt the skin of the ship is in any major climate danger. All indications are that its some form of fairly thick metal alloy
Very thin. Compare the mass of armor to the length and diameter of a typical JumpShip. If you get a millimeter of hull thickness anywhere then it's probably because over the centuries the JumpShip has built up many coats of paint.
(Worse than BattleMechs, BT's large spacecraft have a serious size-to-weight problem. DropShips, WarShips, and JumpShips are aluminum foil balloons.)
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It may very well tarnish in color or even rust in an oxygen-nitrogen environment but it should take many years - decades at least, if not centuries - for rust to eat through the shell of the ship.
I don't see why it'd take that long because, besides thickness, there's little reason to pick corrosion-resistant materials for JumpShip and WarShip hulls. (DropShips are another matter.) I work in an aerospace company designing hardware. If someone doesn't write corrosion resistance to a terrestrial environment into my specifications then I'm going to have a field day using all the great materials and material combinations that I'm normally banned from using.
Currently, if I design an airplane pylon (totally random example, swear) for a customer who puts a lot of jets (and sulfurous jet engine fumes) in a salt spray environment, then I'm probably going to have to design the hardware to survive ASTM G85 (Annex IV: acidified) salt fog testing, probably 336 or more hours. That means painstakingly selecting corrosion-resistant materials like 5000- and 6000-series aluminum alloys, stainless steels (17-4 and 15-5), composites, and heavy coatings (anodize, primer, paint, IVD aluminum, etc.).
Not only that, but I'll have to look with excruciating care at every interaction between different materials. That strong stainless rivet can't go straight into an aluminum frame because you'll get galvanic corrosion, so you'll need to wet install the rivet with epoxy primer or, better yet, corrosion inhibiting polysulfide sealant. That corrosion-resistant composite panel is stuffed full of graphite fibers, which is at the extreme end of the galvanic corrosion chart and is happy to attack any metal it touches so I'll need barriers there, too. Electrical doodads can't have thick, insulating polysulfide sealant along grounding paths (lightning strike and EMI requirements) so there's going to be a problem where the copper grounding strap connects to the aluminum frame.
And every week there'll always be some mechanical or electrical engineer running crying to managers or HR that I'm hitting them over the head with their own rolled up blueprints. Well, sorry, you should know by now you can't design a gizmo for an ASTM G85 environment if it's made out of bare, Alodine "protected" aluminum. I don't care if it's inside the pylon, the moisture will get inside everything. My last job involved almost a decade on DoD corrosion programs, moisture and corrosion always get inside so you need to design for that. I don't care if it's hard and the factory painters will be mean to you, you get that hardware coated, painted, anodized, and (ideally) potted in a block of epoxy.
But in space? Oh, what a glorious day.
I no longer have to settle for mid-strength stainless steel, I can break out the ultra-strong alloy steels that aren't corrosion resistant - beauties like Aermet 340. Wet install with primer or polysulfide? Pfft. The factory operators hate the stink of freshly mixed polysulfide and now I don't have to make them suffer the stench. Galvanic corrosion? Not in a vacuum, sir. I don't need paint, I don't need RTV encapsulation of grounding lugs, I don't have to sweat material interactions, and I can use the strong stuff I'm never allowed to touch because it doesn't have enough corrosion resistance. I just have to worry about stuff like tin whiskers in electronics, off-gassing from adhesives, and humid, oxygenated crew spaces.
Heck, off gassing is great excuse to skip paint. The corrosion control team can bite my JumpShip's shiny metal...stern.
The cost multiplier of DropShips hints at the challenge of designing all environment aerospace vehicles that can operate from subsonic to hypersonic speed in the atmosphere, takeoff and land in salt water, skim stars and land on Pluto. I'd say I wouldn't want that design job, but honestly it'd be decades of job security.
Anyway, between thin skins and no pressing design requirements for corrosion resistance, JumpShips and WarShips would be at significant risk in a terrestrial environment unless they were kept in cool, dry, climate-controlled environments.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Wick
10/14/20 03:35 PM
173.247.25.195
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But if major parts are built on planets and then hoisted up to space-borne assembly complexes, then they would have to worry about things like galvanic corrosion and humidity during construction. Also I'd hope that by the 31st century designers and techs know not to brace aluminum and iron/steel together. Any car repairman these days worth his or her salt knows not to do that, and they've only had a few decades of experience working with the stuff. It a fair point you've made though that design considerations for spacecraft are different than those for atmospheric craft - I think we're all in agreement on this point (and that dropships must be engineered to hell)
I'd assumed that the author intended for the jumpship to be situated on dry land, not on a coast (or aircraft carrier) so it wouldn't need the most rigorous saltwater/seaspray protection. I'd anticipated only a typical amount of water wear from rain with low acidity, but if it is on a coastal city then you've got a point about it needing to withstand more extreme weather. I'd briefly thought hail to be the greatest climatic threat (short of earthquake) but dismissed it because if these things are capable of taking micrometeorite impacts at many thousands of kph then they should take hail at a few dozen kph. (The force equation balances out, as one is ten thousand times faster while the other is ten thousand times more massive.) Also, the plating of jumpships is explicitly defined to be able to take a few shots from weapons fire so I can't easily buy the millimeter thick aluminum foil type of protection. Its likely that's how they'd practically be built, but the game rules say otherwise. I mean, from an astrobiology point of view there would need to be some kind of water or lead lining to protect the crew from cosmic rays - years (or perhaps even months) of exposure outside of a planet's Van Allen belts would be fatal. A water lining demands rust proof material and lead itself is rust proof. Perhaps the uninhabited body and stern of the craft are subject to water damage but the foreward crewed sections should be relatively safe. (Dropships would need to be even more robust as they pass through the Van Allen belts where the radiation is strongest.)
I concur though that a roof is ideal, if not an entirely enclosed building with air filtration to lower the ambient humidity. Its probably easier to put the thing on an inhabitable world with domes rather than a Terran-style world - the weather protection and air quality are already a given in domed cities.
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ghostrider
10/14/20 04:38 PM
66.74.60.165
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Just a point for the dropships and radiation. Some were said to have scooped up materials from sun to fill their fuel tanks. If true, then they have to deal with more then just the radiation belts around worlds.
As for the science of today, it lends weight to the conversation, but how does the future tech change this? The armor for most units has the diamond filament in them, which is not something we have today.
With the information Cray has said, I believe it would lead to removing most of the field work done to the jumpships, as they are very unlikely to have the materials needed for such things as even replacing armor plates. Gas welders would have minute traces of water, and the welding material in an electric one might as well.
Any sort of atmosphere used to work on a jumpship would have issues as well.
And jumpships would have to deal with gravity issues when build near say Jupiter or Saturn as the Titan shipyards would be. Even just in the orbit, and not around the worlds would produce gravity issues.
This would also suggest the Iceships could not even be possible, as it would destroy the iceberg or the other ships. So does that mean the Iceships were just put in to make a more fantastic story? Or was it possible, even with the limitations of the ships given here?
If they could envelope the entire fleet with one jump 'portal', that would mean it would be possible to move other things, like battle stations or just normal stations in one piece. Dangerous, no doubt, but possible.
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Wick
10/17/20 12:51 PM
173.247.25.195
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Just a point for the dropships and radiation. Some were said to have scooped up materials from sun to fill their fuel tanks. If true, then they have to deal with more then just the radiation belts around worlds.
These are Bussard collectors for collecting hydrogen to power the fusion engines. A lot of science fiction uses this same concept. You just collect interstellar hydrogen cast off by solar wind as you travel (or park for recharge.) As I understand it, jumpsails themselves are just giant Bussard collectors, though shaped like a sheet rather a funnel or a cone. Bussard collectors and jumpsails are mounted outside the habitable areas and even after centuries of use they shouldn't be irradiated to the point of being dangerous to human contact so radiation shielding is effectively moot.
The greatest dangers from radiation are to organic tissue - the crew - not the metallic craft, except for electrical components (which could be radiation-hardened.) I could only imagine it being a serious issue if a warship decided to play around in a star's corona. This would endanger the crew much more seriously than the ship though, so I don't think it likely a jumpship is heavily irradiated unless the ship was abandoned, happened to fall into a close orbit around a star or large gas giant, and someone desired salvaging it.
Probably true that future tech has some better means of protecting from radiation. Battletech doesn't have forcefield-based "shields" so it must be armor or exterior plating. Polarizing the hull sounds like it could work, except you couldn't have Battlemechs walking around on the outside like described in canon, so its got to be something in the exterior metals.
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And jumpships would have to deal with gravity issues when build near say Jupiter or Saturn as the Titan shipyards would be. Even just in the orbit, and not around the worlds would produce gravity issues.
Gravity in orbit around a moon of Jupiter or Saturn is negligible. This is going to be far less than the 0.1 G they can travel at. While they have tremendous gravity compared to Earth, you have to remember that they are much larger in diameter - at the tops of Jupiters clouds the "surface" gravity is just 2.5 G. And at Saturn its just over 1 (1.065 G.) Out where the moons orbit a dropship, jumpship, or iceship would have no trouble at all counterbalancing the gravitational pull. Our tiny little spacecraft today can do it with just a few puffs of hydrazine - we'd never have orbiters like Juno or Cassini if the gravity was so strong to suck them in or tear them apart.
The real danger is the magnetospheres of gas giants like these. They have the exact same effect as the Van Allen belts around Earth (which are driven by Earth's magnetosphere) and act as a giant radiation collecting torus around the planet (but even stronger than Earth's.) Titan is on the outer edge of Saturn's magnetosphere so its possible to have the Titan Shipyards there, but Iapetus would make a safer port being further out.
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