Jump Shadowing/Masking

[Tenacious-Techhunter]

If you wanted to get specific, not all massive objects are spherical, hence their area of affect wouldn't necessarily be a sphere, more like an ellipse. But for game mechanic purposes, the 100D rule works.

Barring a radically fast planetary or star rotation, yes, all planet-sized bodies are very spherical. Unless they are Ancient Artifacts, or other Big Dumb Space Objects. It’s a gravitation thing, related to the phenomenon where a sand pile on a planet of a given gravity can only have so steep a slope... the higher the gravity, the smaller the slope, and the more spherical the planet.

The game mentions that you can't fly through an object, such as the sun, but I think most people don't try to plot out specific courses when making jump navigation plots. You'd think most ships would arrive above/below the system plane ecliptic to minimize jump shadows.

It depends on what approach you want. If the planet you want is jump-shadowed, you might want a gravity boost off of a nearby planet to slingshot you to port faster. If it isn’t jump-shadowed, it’s better to target the planet directly. Options for gravity boost out also, as relevant to your intended outward bound trajectory.

"Oops, it turns out your system charts you downloaded were out of date by 10yrs, thus that gas giant was out of place and pulled out you of jump space. Oooh! Lookee there! A ship is nearby..."

... No. Even a basic Jump Tape, and not even a whole Jump Database, is going to give you every modeling detail necessary to know when and where all the relevant space objects in the target system are going to be up to hundreds of years in advance... “relevant” being decided by how well-paid the people who charted said objects in said system were at the time it was charted to get it right... or even to get it conveniently wrong... see “Space Pirates”.

 

[Tenacious-Techhunter]

Gravitons are theoretical particles and their existence has not been proven, so your "reasonable physical justification" goes out of the window right there. The rest of your justification is just technobabble-y armwaving.

Gravitons are the only current plausible justification for how Gravity as a force is transmitted. Yes, the actual mechanism may wind up not resembling it at all; but, frankly, it’s the best we’ve got. You want to pull on something with extra Gravity? You fire extra Gravitons at it. That’s the only plausible justification we have for Gravity, so far. I’m not going to apologize for not beating all of Science with a better theory on how Gravity works.

Nope. Asteroids and comets can have a 100D too. Nebulae and dust clouds don't, so the physical density of the material does matter (though that can be pretty low, since hypergiant and supergiant stars also have 100D limits and they are very low density). The lower limit to what has a 100D limit has not been established. I think T5 would have us believe that absolutely everything (including spaceships) has 100D limits, but I would prefer an arbitrary limit like 1 billion metric tons or something like that, so that a floating spaceman doesn't mess up jump.

My theory as to how Jump Drive works, as stated, would indicate that there’s a “floor value” tied to the robustness of the Jump Drive’s ability to repair “graviton holes” that keeps smaller things from doing sustained damage to the Jump Bubble. I would argue enough small things would overwhelm that limitation, but it would have to be like Spartans fighting in the shade to matter.

 

[Tenacious-Techhunter]

Siri, TL8:
well that was a small part of:
We can easily see that it takes no tonnage, and is basically free.

That’s an entire planet’s worth of Siri... how much is just one? Or just a ship’s worth? It’s not even one slot in that rackmount.

 

[fusor]

Every object, at a distance 100D from that object, appears to be the same size as other objects you are 100D of that other object from that other object. At 100D of the Sun from the Sun, the Sun looks almost exactly the same size as the Moon 100D of the Moon from the Moon. They both take up the same “area” within the scope of your vision. Which means, if we assume their gravitons can punch through Jump Bubbles, they would also punch the same size hole through your Jump Bubble, hypothetically leading to the same Jump Bubble collapse.

So the angular diameter is the same for all objects at the 100D limit - if you were at the 100D distance of a neutron star, Sun, Jupiter, Earth, Sirius, or Arcturus then they'd all appear to be about 0.57 degrees across in the sky (slightly bigger than the full moon in our sky). That's interesting, but I don't think it's really relevant to anything for two reasons: First, gravitons don't appear to exist (and the evidence is against them too, much like tachyons), and they wouldn't "punch holes" in anything even if they did. Second, the gravitational field strength at that distance would be different for all those objects anyway.

Gravitons are the only current plausible justification for how Gravity as a force is transmitted.

It's a huge stretch to say they're "plausible" at all, when there's no evidence for them at all (and they can't even be detected either). Gravity is due to the curvature of space-time, for all we know there aren't any particles involved in that whatsoever.

It's best if people stopped trying to bring gravity into it, and just accepted that it's a limit based on size. Personally, I'd armwave it away by saying that it's to do with how the extra dimensions of jump space interact with the normal universe, and while gravity may have something to do with it, it's "flattened" so that the important relationship is related directly to distance instead of (distance)². Or something. Whatever. It just doesn't matter at all.

Either way, we're going way off canon now, and as I keep saying, the mechanics of what makes the 100D limit the limit are not important to anything in Traveller, and certainly aren't important to calculating jump masking or shadowing. As it is, GURPS Traveller is pretty much the only version of the game to really attempt to tackle those, and it does it in a rather convoluted way involving tables and calculations and some sweeping assumptions that frankly don't really add that much to the game beyond more complication. It's a worthy attempt, but about as practically useful as one would expect given the problem it's trying to solve.

 

[Reynard]

"Are you implying here that a ships sensors would be operational and detecting things in realspace while it was in jump space? That would be a departure from the rules as they have been stated"

We are told the ship, for all intents and purposes, is completely isolated from real space. All well and good but reading all the info on jump I realize they keep mentioning how jump space and either the jump drive or merely the jump 'bubble' is affected by real space gravity. Made me think if the ONLY force that can reach into jump space is gravity then could that also affect a gravity sensor? I was speculating. It could be the influence is on a difference level not entirely understood except for the correlation with precipitation. I may be considered wrong there though gravitometers could still exist for use in real space.

T-T, there's a bit of artifact copy. I need to reread 2nd Ed. concerning wording but a ship's computer is and has been considered a separate component for ship design. It is not initially integral with the bridge and it's components but ties in with the bridge and all components aboard the ship. "Adjacent to the bridge' should now mean spread through the ship with a main component at the bridge but that's long winded. Even I have learned the word 'large' refers to both the built in software and the hardware needed to drive the processing ability plus there's the physical connections, dedicated computers and such spread all over the ship sending vast amounts of data to be analyzed and acted upon in a virtual blink of an eye. Higher price yet no actual larger volume indicates what we see in today's machine, we pack more powerful and sophisticated components into the same space but at higher prices. Again, I need to see if they worded it better in 2e.

"Bull@^*%. Name one piece of software that legitimately requires an oversized computer beyond elaborate entertainment software. Not Maneuver, not Evade, not Fire Control... Jump Control is a false argument, since that can be as complex as the fiction authors want it to be... "

Not the software per se but the processing power needed to run calculations very, very fast. And we have always been given the impression jump space travel is not the same as an airplane on auto-pilot. That's true even today. Also remember a ship's computer isn't just running a program or two, it's running a starship or just a spaceship. Today's tablets might be fast and compact but they still aren't running power plants or naval carriers both of which are simple compared to a starship's functions. We have outfits that ask thousands of computer owners to let their computer be linked as if a gigantic computer array. A very large computer. Lots of processing needs more components, connections and cooling. Yes there are still big computers; we miniaturize them a little, expect to process more and need more computer to do it.

"Uh... no it doesn’t... we’re only changing a handful of variables... mass, inertia about 3 axes... It’s still the same basic math problem!"

Really?! You personally know all about jump space and how to calculate a jump? Say the same to most science labs especially those who need those global computer arrays to solve their 'basic math problems'! I'll believe the people who decided their creation is THAT kind of hyper complex to need very powerful processors. Why not go make it clear to astronomers an Apple II is good enough to analyze star data.

 

[phavoc]

If you wanted to get specific, not all massive objects are spherical, hence their area of affect wouldn't necessarily be a sphere, more like an ellipse. But for game mechanic purposes, the 100D rule works.

Barring a radically fast planetary or star rotation, yes, all planet-sized bodies are very spherical. Unless they are Ancient Artifacts, or other Big Dumb Space Objects. It’s a gravitation thing, related to the phenomenon where a sand pile on a planet of a given gravity can only have so steep a slope... the higher the gravity, the smaller the slope, and the more spherical the planet.

I was referring to planetoids, or smaller moons that would be massive enough to cast a jump shadow, just not as large as a planet. Both Deimos and Phobos are irregularly shaped. And other larger asteroids are far longer than they are wider. I'm not saying a planet would be that, but there's still much for us to discover in space. We just don't have the mass threshold where at what point an object becomes capable of affecting a jump field. References exist in various rules versions.

It depends on what approach you want. If the planet you want is jump-shadowed, you might want a gravity boost off of a nearby planet to slingshot you to port faster. If it isn’t jump-shadowed, it’s better to target the planet directly. Options for gravity boost out also, as relevant to your intended outward bound trajectory.

Even with gravity boost you still must first clear the jump shadow of the star/gas giant/planet that is in your way. All a grav boost does is increase your speed beyond what your drives can provide on their own. And with the ability to constantly boost, the time required to get the boost may not be worth it (or possible around a regulated orbital zone).

"Oops, it turns out your system charts you downloaded were out of date by 10yrs, thus that gas giant was out of place and pulled out you of jump space. Oooh! Lookee there! A ship is nearby..."

... No. Even a basic Jump Tape, and not even a whole Jump Database, is going to give you every modeling detail necessary to know when and where all the relevant space objects in the target system are going to be up to hundreds of years in advance... “relevant” being decided by how well-paid the people who charted said objects in said system were at the time it was charted to get it right... or even to get it conveniently wrong... see “Space Pirates”.

Did you miss the part where I said your system charts were out of date? If you didn't have the star charts for the system you were going to, and the ones you got had the planetary rotations 10yrs in the past, then yeah, it's entirely possible for such a thing to happen. We are talking about a 100D rule here, so if you plotted a planets position incorrectly it can affect you. I didn't say the planet was a surprise, I said WHERE it was SUPPOSED to be was the surprise. Two entirely different issues here. And before you say it, no, I don't agree that a ship is going to carry every systems orbital charts in memory. Why? Because if you don't or have never travelled to that particular region, there's no purpose in keeping that sort of data stored. Even with massive storage capabilities, the idea behind efficient data storage is to keep what is relevant or potentially useful. Would you carry Solomani sphere system charts if you were a ship in the Spinward Marches? No. Would you carry Lunion sub-sector charts if you never left the Regina sub-sector? No. IF you needed them, you'd pick them up prior to travelling there, or upon arrival at the edge. That's just common sense.

And if you recall from Classic Traveller, there was an adventure related to updating system maps of the Spinward Marches. Granted planets generally don't change their orbits that much, but smaller planetary objects do, any of which could be pushed/pulled/impacted into new orbits that cause navigational hazards. Ergo it's a good idea to get updated star charts whenever you plan on travelling to an area. Hence the possibility of error creeping in and you getting incorrect ones. Or are you saying that neither human nor machine error is possible in the far future?

 

[Tenacious-Techhunter]

First, gravitons don't appear to exist (and the evidence is against them too, much like tachyons), and they wouldn't "punch holes" in anything even if they did. Second, the gravitational field strength at that distance would be different for all those objects anyway.

It’s not that “they don’t appear to exist” per se; just that there is no evidence for them. Their existence or not is an entirely open question. And they might well not exist. But if they do, then my explanation is viable.

Gravitons are the only current plausible justification for how Gravity as a force is transmitted.

It's a huge stretch to say they're "plausible" at all, when there's no evidence for them at all (and they can't even be detected either). Gravity is due to the curvature of space-time, for all we know there aren't any particles involved in that whatsoever.

You neglected to take what I said at face value. If Gravity is not transmitted at all, then there’s no need for Gravitons; but if it is, then it’s a viable explanation.

It's best if people stopped trying to bring gravity into it, and just accepted that it's a limit based on size.

No, it’s best if we dump it altogether for something more realistic. Until then, we might as well find a way to justify it.

 

[fusor]

Getting back to something actually useful and relevant to the topic, it occurred to me that jump shadows/masking would force a kind of schedule on starports - namely, that ships would usually be cleared to launch when the star they're going to is above the horizon at nighttime. Why? Because that means that the most direct route to the star is open. All the ship has to do is take off, point at the star, travel to the planet's 100D limit, and then it's a clear jump out from there. Though if the planet is very close to its star (e.g. orbiting a red dwarf) then it may have to travel further to the star's 100D lmit beyond that, but the point is that it's still pretty direct.

If the star is not above the horizon though, the ship has to take off and then orbit around the planet because the planet's 100D limit will be blocking its path to the destination system. So that costs time (though in Traveller it won't cost much in the way of fuel, which means the economical restriction here is rather less strict).

And if the star is above the horizon and the sun is up, then the sun's 100D limit is very likely to be blocking the route to the destination system (unless the latter is far above or below the ecliptic plane, in which case it may not matter). That means even more travel time to get clear to jump, which would be bad.

And since the planet is orbiting its sun, that may mean that stars will be blocked off for certain times of its year. For planets with short orbital periods (i.e. habitable worlds around red dwarfs. Though they have the added complication of being tidelocked to the star) that's not a huge delay - a couple of weeks may be required for the planet to swing around the sun so that the destination is not blocked by the sun's 100D limit, but for planets further away from the star that becomes a more significant problem since the year is longer. In those cases the ship would be forced to travel laterally out from the planet a significant distance to get beyond the star's 100D limit, which adds a lot more travel time. For Giant stars it's a crippling problem because the orbit is centuries long, and the ship would therefore have no choice but to travel very far from the planet before it gets a clear line of sight to the destination that doesn't intersect the star's huge 100D limit, which would add a possibly impractical amount of time.

 

[Tenacious-Techhunter]

We are told the ship, for all intents and purposes, is completely isolated from real space. All well and good but reading all the info on jump I realize they keep mentioning how jump space and either the jump drive or merely the jump 'bubble' is affected by real space gravity. Made me think if the ONLY force that can reach into jump space is gravity then could that also affect a gravity sensor? I was speculating. It could be the influence is on a difference level not entirely understood except for the correlation with precipitation. I may be considered wrong there though gravitometers could still exist for use in real space.

If gravity can affect the shape of the Jump Bubble, then scans of the Jump Bubble’s shape can lead to gravimetric data about the outside world. Sounds good to me.

T-T, there's a bit of artifact copy. I need to reread 2nd Ed. concerning wording but a ship's computer is and has been considered a separate component for ship design. It is not initially integral with the bridge and it's components but ties in with the bridge and all components aboard the ship. "Adjacent to the bridge' should now mean spread through the ship with a main component at the bridge but that's long winded. Even I have learned the word 'large' refers to both the built in software and the hardware needed to drive the processing ability plus there's the physical connections, dedicated computers and such spread all over the ship sending vast amounts of data to be analyzed and acted upon in a virtual blink of an eye. Higher price yet no actual larger volume indicates what we see in today's machine, we pack more powerful and sophisticated components into the same space but at higher prices. Again, I need to see if they worded it better in 2e.

Not the software per se but the processing power needed to run calculations very, very fast. And we have always been given the impression jump space travel is not the same as an airplane on auto-pilot. That's true even today. Also remember a ship's computer isn't just running a program or two, it's running a starship or just a spaceship. Today's tablets might be fast and compact but they still aren't running power plants or naval carriers both of which are simple compared to a starship's functions. We have outfits that ask thousands of computer owners to let their computer be linked as if a gigantic computer array. A very large computer. Lots of processing needs more components, connections and cooling. Yes there are still big computers; we miniaturize them a little, expect to process more and need more computer to do it.

No. Even as you state it there, that’s unrealistic. It is simply unnecessary for a Ship’s Computer to be larger than a toaster for those purposes. Regardless of speed issues or throughput issues, there’s no need for a computer of that size. The Raspberry Pi 3 is a 64 bit, 4 core, 1GHz machine. 4 will fit in a toaster. It’s more than enough to simulate the N-Body Problems of 2 Star Systems simultaneously, and the resulting implications of Ship Maneuvers, Turret Slewing, and Weapons Fire. Future models will be even more overkill for these tasks, meaning an even smaller computer would do... but would be more difficult to repair. Repair issues are the only thing that are going to keep a Ship’s Computer from getting even smaller.

The reasons that tablets don’t run power plants and Naval Carriers is not because they can’t... it’s because they’re the wrong form-factor for the job. No one wants that sort of computer to be easily stolen. There’s also a lot of inertia in redeveloping a ship’s software for a more efficient platform that leads to slower adoption of more appropriate technology for a given job.

Really?! You personally know all about jump space and how to calculate a jump? Say the same to most science labs especially those who need those global computer arrays to solve their 'basic math problems'! I'll believe the people who decided their creation is THAT kind of hyper complex to need very powerful processors. Why not go make it clear to astronomers an Apple II is good enough to analyze star data.

Now you’re just being ridiculous. The physics problem is the same. It’s only the variables that are different. Somehow, the authors are trying to imply that there are considerably more variables than there used to be... which is just plain absurd. Physics is physics is physics; it doesn’t matter that the physics is made up... if there aren’t more variables, there’s no additional complexity. If there were additional variables for a larger ship, there would be additional variables for a larger planet... which is insane; why should a planet have additional variables just because it’s larger?.

And, for the record, Astronomers have used Apple IIs to analyze star data... not that they wouldn’t spend a few bucks to use something better today.

 

[fusor]

Look, can you two please bugger off and argue about gravity and computers elsewhere? You've derailed the thread enough as it is.

 

[Tenacious-Techhunter]

I was referring to planetoids, or smaller moons that would be massive enough to cast a jump shadow, just not as large as a planet. Both Deimos and Phobos are irregularly shaped. And other larger asteroids are far longer than they are wider. I'm not saying a planet would be that, but there's still much for us to discover in space. We just don't have the mass threshold where at what point an object becomes capable of affecting a jump field. References exist in various rules versions.

Yes, smaller objects can be irregular... but even those examples are “spherical enough”, at least for game purposes.

It depends on what approach you want. If the planet you want is jump-shadowed, you might want a gravity boost off of a nearby planet to slingshot you to port faster. If it isn’t jump-shadowed, it’s better to target the planet directly. Options for gravity boost out also, as relevant to your intended outward bound trajectory.

Even with gravity boost you still must first clear the jump shadow of the star/gas giant/planet that is in your way. All a grav boost does is increase your speed beyond what your drives can provide on their own. And with the ability to constantly boost, the time required to get the boost may not be worth it (or possible around a regulated orbital zone).

You missed my point; if you want the gravity boost, you’re aiming to wind up within the orbital plane, preferably near the object you want a slingshot from, whether it’s in Jump Shadow or not. Otherwise, a direct course, within the orbital plane or not, is best. You can save a lot of time in the destination system if you plot your Jump carefully to take advantage of the physics available to you there.

Did you miss the part where I said your system charts were out of date? If you didn't have the star charts for the system you were going to, and the ones you got had the planetary rotations 10yrs in the past, then yeah, it's entirely possible for such a thing to happen. We are talking about a 100D rule here, so if you plotted a planets position incorrectly it can affect you. I didn't say the planet was a surprise, I said WHERE it was SUPPOSED to be was the surprise. Two entirely different issues here. And before you say it, no, I don't agree that a ship is going to carry every systems orbital charts in memory. Why? Because if you don't or have never travelled to that particular region, there's no purpose in keeping that sort of data stored. Even with massive storage capabilities, the idea behind efficient data storage is to keep what is relevant or potentially useful. Would you carry Solomani sphere system charts if you were a ship in the Spinward Marches? No. Would you carry Lunion sub-sector charts if you never left the Regina sub-sector? No. IF you needed them, you'd pick them up prior to travelling there, or upon arrival at the edge. That's just common sense.

No, you missed the part where orbital physics is very predictable, and from a known set of carefully gathered data, provided by, say, the Scout Service, physical models of the target system will be good for hundreds of years... Just like how we can know what the night sky looked like at some random date thousands of years ago. Gas giants don’t just up and walk away!

Your points about storage are pretty ridiculous too.

And if you recall from Classic Traveller, there was an adventure related to updating system maps of the Spinward Marches. Granted planets generally don't change their orbits that much, but smaller planetary objects do, any of which could be pushed/pulled/impacted into new orbits that cause navigational hazards. Ergo it's a good idea to get updated star charts whenever you plan on travelling to an area. Hence the possibility of error creeping in and you getting incorrect ones. Or are you saying that neither human nor machine error is possible in the far future?

I’m saying that Gas Giants aren’t moved out of place by people over the course of 10 years. Smaller things, yes, they move, but only if people move them... which will happen from time to time. Regardless, the local system-wide version of NORAD will send copies of the updated system navigation hazards out with the mail, and also by light-based communication methods, which will reach nearby star systems that haven’t heard for whatever reason in the time it takes that light to get there.

 

[Tenacious-Techhunter]

Getting back to something actually useful and relevant to the topic, it occurred to me that jump shadows/masking would force a kind of schedule on starports - namely, that ships would usually be cleared to launch when the star they're going to is above the horizon at nighttime. Why? Because that means that the most direct route to the star is open. All the ship has to do is take off, point at the star, travel to the planet's 100D limit, and then it's a clear jump out from there. Though if the planet is very close to its star (e.g. orbiting a red dwarf) then it may have to travel further to the star's 100D lmit beyond that, but the point is that it's still pretty direct.

...

Not counting gravity boosts from planets near your intended path, honestly, on any given day, the time to launch is going to be dictated by the fastest possible brachistochrone trajectory to the half of the 100D sphere facing your target system, and not any rule of thumb about a specific time of day.

But, for about half the year, in the most advantageous parts of the year, midnight launches from spacedock and pre-midnight launches from the ground will get you to that 100D half-sphere fastest. The rest of the year will depend on complicated physics.

 

[Condottiere]

You can state an arbitrary minimum volume of an object that can affect transdimensions through it's inherent gravitic influence, so that pebbles become irrelevant to game mechanics.

I'll go with a minimal fourteen hundred cubic metres.

 

[Sigtrygg]

The actual, realistic computational workload of simulating the n-body problem of a ballistic trajectory that bypasses several such systems actually would fit on a Raspberry Pi 3. Add a few more in a box the size of a toaster for redundancy. The idea of the “ship’s computer” being a massive giant is obsolete. There is no scientific justification for it. NASA’s computers may be bigger, but they’re trying to solve a harder problem... meeting the same trajectory goals while desperately conserving costly fuel. Fuel isn’t costly in Traveller; nor is its conservation particularly desperate. Removing this one constraint radically simplifies the math problems to be solved. Also, the targets in Traveller are way bigger, way easier to hit, and hitting the 100D limit of any planet or star in the system is a plenty good enough fallback that is trivial to calculate as well.

Traveller GMs need to kill their inner luddite, take a damn look around at the actual, measurable capabilities of modern hardware, and realize they’ve been GMing a damn lie. The size and power requirements of an average hobbyist gaming rig is going to completely dwarf even the biggest Navigation Computer any ship is likely to need.

Absolute bull.
The data alone takes up terrabytes. And that is for normal space - take into account multi-dimensional hyperspacial factors and instead of integrating 6 dimensions you are looking at 12 minimum, probably more.

 

[Sigtrygg]

Well, Mongoose Traveller 1E still had unnecessarily oversized computers and cockpits, so you’re the one that’s less informed.

Again bull.
The computer in even a smallcraft is running artificial gravity, acceleration compensators, a gigawatt fusion power plant, avionics, environmental control and possibly minecraft all at the same time.
How big are the computers that run a boomer? Or a CVN? And by run I do not mean the tablet interface but the actual server racks etc.

Here's a thought - why don't you tell the F35 designers that they can solve all of their issued with its computer issues by just pugging in a toasters worth of raspberry-pi boards.?

 

[Sigtrygg]

And now since we have been asked to shut up about computers and their fictional capability at TLs way above ours.

In order to bake jump masking and jump shadowing into the basic game you will need to include star type on the UPP, and not just the extended system data that most people don't bother with.

(Assuming you accept the concept, which I don't and never will use IMTU - see T5 for law of unintended setting breaking consequence)

In order to speed things up the 100D limit for the star and the relative position of the mainworld (to the star's 100D limit) needs to be included too.

Maybe a table to look stuff up would make it more playable...

 

[phavoc]

You missed my point; if you want the gravity boost, you’re aiming to wind up within the orbital plane, preferably near the object you want a slingshot from, whether it’s in Jump Shadow or not. Otherwise, a direct course, within the orbital plane or not, is best. You can save a lot of time in the destination system if you plot your Jump carefully to take advantage of the physics available to you there.

Why in the world would you want to remain in the elliptical plane if you could avoid doing so? If your destination is on the far side of the system, and even if it is not, it's far better to travel above or below so that you can avoid the vast majority of spatial objects that are IN the elliptical plane. Every system will be different, of course, but there's no real disadvantage from staying away from it whenever possible.

And what do you mean about saving "a lot of time" in the destination system? If you arrive at 100D above, at, below or anywhere from your target, your travel time to the planetary surface remains the same. That 100D is a sphere, ergo you are equidistant to your objective wherever you arrive. And with even a minimal 1G capability, the fact that your arrival destination is on the opposite side of the planet is trivlal from a time perspective.

No, you missed the part where orbital physics is very predictable, and from a known set of carefully gathered data, provided by, say, the Scout Service, physical models of the target system will be good for hundreds of years... Just like how we can know what the night sky looked like at some random date thousands of years ago. Gas giants don’t just up and walk away!

Your points about storage are pretty ridiculous too.

/snark on

Do you take the time to read what you type? Or do you just HAVE to be right all the time with your smug opinions that you blithely move past what people are saying? But hey, let's go with your example here. Using your description of orbital mechanics as being very predictable, let's add a few more variables. Gravitation of a body is a known variable, let's use Mars for an example. Atmospheric drag is a knownvariable, let's use Mars again. And math. Math is a known variable, too, right?

Now, let's put all those together and let's use math and science to launch a space probe to Mars from Earth. Still with me? Okay. Now, let's throw in some really smart people, let's call them Rocket Scientists, and let's have them be employed by places like JPL, and Lockheed Martin and NASA. Whee! We've got a rocket ship traveling to Mars now!!! And let's say we get there in one piece. Let's, oh, I dunno, let's call our theoretical rocket payload the Mars Climate Orbiter. Everybody knows that pounds-seconds and newton-seconds are different, right? Oh, and toss in the fact that this discrepancy was spotted by humans, but dismissed by other humans. Now do tell me what happens when you feed pounds-seconds data to a program that is operates your thrusters and it is expecting the data to be in newton-seconds? It would be pretty ridiculous to expect such really smart people to make an error that is taught to every child who learns basic science and math, that when you have two different systems you have to convert one to the other in order for it to properly be able to be interpreted correctly. Really smart people like rocket scientists are taught that lesson over and over and over, because, yanno, math!

Tell me how ridiculous that sounds please. Like this couldn't happen?

Yeah, thought so.

/snark off

You bring up some valid points, but if anyone disagrees with you then they are wrong and you have to PROVE them wrong. Except that you can't. Why? Because we are discussing a game set in the 52nd century that is only loosely based on real science. Maybe you have missed the sci-fi RPG label it gets? Sci-fi, for your edification, means science fiction. Ergo there is BOTH science AND fiction present in the gaming setting. Emphasis on gaming.

I’m saying that Gas Giants aren’t moved out of place by people over the course of 10 years. Smaller things, yes, they move, but only if people move them... which will happen from time to time. Regardless, the local system-wide version of NORAD will send copies of the updated system navigation hazards out with the mail, and also by light-based communication methods, which will reach nearby star systems that haven’t heard for whatever reason in the time it takes that light to get there.

You still don't want to get it here, do you? Ships aren't going to have star charts of every single system known simply because they have the petabytes to store the data. If that was the case then why don't commercial pilots carry maps and landing information for every major airport in the world in their flight bags on their iPads? Why? Because a guy flying the NYC - London route doesn't need to know the approach pattern to Narita. To CDG, or Belfast or even Frankfurt am Main, sure, but not Narita. The same logic would be used in the future. Even with virtually unlimited storage, people are going to start finding ways of filling that space up. Hell, cat videos in the future will number in the quintillions probably, and I bet they will use space in their prodigious memory banks for those before they'll store the orbital information for all significant planetary bodies in the known universe.

Why? Because humanity. And cat videos. Two things that change, but really don't.

 

[fusor]

Do you take the time to read what you type? Or do you just HAVE to be right all the time with your smug opinions that you blithely move past what people are saying? But hey, let's go with your example here. Using your description of orbital mechanics as being very predictable, let's add a few more variables. Gravitation of a body is a known variable, let's use Mars for an example. Atmospheric drag is a knownvariable, let's use Mars again. And math. Math is a known variable, too, right?

Now, let's put all those together and let's use math and science to launch a space probe to Mars from Earth. Still with me? Okay. Now, let's throw in some really smart people, let's call them Rocket Scientists, and let's have them be employed by places like JPL, and Lockheed Martin and NASA. Whee! We've got a rocket ship traveling to Mars now!!! And let's say we get there in one piece. Let's, oh, I dunno, let's call our theoretical rocket payload the Mars Climate Orbiter. Everybody knows that pounds-seconds and newton-seconds are different, right? Oh, and toss in the fact that this discrepancy was spotted by humans, but dismissed by other humans. Now do tell me what happens when you feed pounds-seconds data to a program that is operates your thrusters and it is expecting the data to be in newton-seconds? It would be pretty ridiculous to expect such really smart people to make an error that is taught to every child who learns basic science and math, that when you have two different systems you have to convert one to the other in order for it to properly be able to be interpreted correctly. Really smart people like rocket scientists are taught that lesson over and over and over, because, yanno, math!

Tell me how ridiculous that sounds please. Like this couldn't happen?

Yeah, thought so.

Both are utterly unrelated points.

The orbits of an object can be stored in six variables. Yes, six. All the orbital data for every object known in the solar system wouldn't even take up more than a few megabytes of storage at most. Certainly not "petabytes".

What happened with MRO was an idiotic mistake born from budget cuts and human error. It's nothing to do with knowing where Mars is.

 

[Sigtrygg]

And the computers that do the calculations are Earth based supercomputers, not a few chips on the robot itself.

 

[fusor]

And the computers that do the calculations are Earth based supercomputers, not a few chips on the robot itself.

Nope. Normal computers at most. They're really not that complicated.
(how do you think NASA managed to send probes to Mars and the outer planets in the 1970s? How do you think the Soviets landed on Venus in the 1980s? "Supercomputers" weren't needed for that. You can do the calculations in Excel, for crying out loud. Heck, the dynamicists probably used slide rules in the 60s and 70s).