Hyperdrive speeds

[PainRack]

Here's a theory I want to bounce off you guys, something that's been nagging me between the variance in speeds seen.


Instead of there being a top speed for hyperdrive, why shouldn't there be a top acceleration instead? Curtis Saxton old Technical commentaries once mentioned that the lightspeed barrier is the bit that's requires energy to work towards, if you're travelling past lightspeed, you need more and more energy to slow down, and it requires less and less energy to speed up.

So, starships that were making extremely long jumps, through space free of debris and other gravitational wells might be able to make extremely long journeys faster than shorter legged jumps, as they have more room to ramp up the speed instead. There's bound to be some limitating factor, say perhaps, the ship structural intergrity which limits just how much faster than light you can go, or the rates of acceleration, or the increased risk of castrophic damage when you're passing near a gravitational well. Say, if you're travelling at 300 lyh and your ship is rated at class 1, your ship can withstand going past Tatooine at 1 AU but can't if you're travelling at 1 thousand LYH. But if your ship is rated at class 0.5, you can.


This gives a slightly different twist to the Kessel Run retcon, in that instead of the ship speed being the factor causing the run, perhaps its the ship..... structural ability to withstand higher hyperdrive accelerations closer to the black holes....

It also sorta explains why hyperspace lanes still retain the great importance they do in SW post Galactic Empire and why its so hard to simply replicate more lanes. A ship travelling long distance between Corellia and Coruscant might well require that lane to achieve such high speeds, because its in that region where the wells are mapped well enough, as well as the region of space being suitable for running your ship at such fast speeds.

[Baffalo]

IIRC, the Kessel Run was a measurement of distance rather than actual time, since many who tried to get too close to the black holes wound up getting trapped inside, so I highly doubt it's meant to represent the abilities of hyperdrive, at least in the context of how they work. Hyperdrives are supposed to only function when clear of gravitational bodies, and even shut down when they detect them, so obviously there's an acceleration curve here, but that is entirely dependent on the sensors being used, not the actual abilities of the hyperdrive itself.

The classifications given for hyperdrives is a quirky issue and one that is a big pain in the ass. According to Wookiepedia, hyperdrives are rated lower and lower as they achieve 'infinite' power, so the lower the class, the faster they go. Well, if that's the case, the argument could be made that we're dealing with a bell curve like you describe, with the peak being Infinite Energy and the ends being zero relative motion to the rest of the universe.

If you're using this bell curve to calculate how much energy is needed to accelerate up to a certain point, you don't read it as simply being "I want 95% the speed of light so I'll just pick that point and that's my energy". No, you must work from left to right... you must account for the energy you spend getting up to that speed as you accelerate, meaning that when you have reached the 95% mark, everything under the curve from 0 to 95 is represented. This bell curve is inaccurate because it doesn't peak, it just continues to infinity, but you get the gist of it.

So, in order to expend energy to reach class 0, you need to encompass nearly all the energy in both universes. Just like before, when dealing with the speed of light, it never really ends... it just goes on and on and on and on and on.

In conclusion, you are indeed correct that it is a top acceleration, but it's also a top speed as well. You can only accelerate if you have the energy to accelerate, and after a certain point no matter how much energy you put into the system, your acceleration eventually drops to 0.

[LaCroix]

According to dialogue, the 'Kessel run' statement was a rebuttal to the 'piece of junk'. So it mustn't refer to light speed, only to real-time acceleration, which is an independent system. He could as well have used it to state how durable the Falcon is.

[Purple]

Well if what I have read about it in this thread and others so far is true and the Kessel Run is a messed up route with all sorts of black holes and stuff. Those might well exert some sort of effect over any craft going past them even if it is not pulled out of hyperspace and crushed by them. So his statement might actually be about the ships durability and how it can withstand those forces without getting ripped apart.

[Crazedwraith]

Obi-Wan: Is it a fast ship?
Solo: You've never heard the Millenium Falcon?
Obi-Wan: Should I have?
Solo: It's the ship that made the kessel run in 12 parsecs. She's fast enough for you old man.

That's the context. How does it make any sense that he's refering to anything except speed? The discussion is explicitly about how fast the ship is.

[Baffalo]

Wookiepedia states the Kessel Run is normally through a thick asteroid field inside a nebula, but Han managed to skirt the edge of the Maw, not the asteroid field, so that's how he was able to do it. According to the Han Solo trilogy, he did it in 11.5 parsecs, versus the standard 18 parsecs.

[Darth Tedious]

Yeah, isn't the whole Kessel Run bit more about the ship's AWESOME LEET navicomputer? The fact that it was able to plot a shorter (read more risky) course, makes the ship faster (to a destination) but not actually faster (higher velocity travel).

That aside, I totally like Painrack's theory. It certainly explains why hyperspace lanes were so vital.

[Connor MacLeod]

Not unusual. It's been mentioned before in the Lando Calrissian adventures about FTL being acceleration rather than pure velocity. When you think about feats like 'changing course in hyperspace' as some ships can do, it wouldn't be surprising (particularily for extremes, where you hyperdrive AROUND a planet, like in Jedi Council: Acts of War)

The Millennium Falcon’s velocity, many times greater than that of light, was limited only by the density of the interstellar medium she traversed. Ordinary space is mostly emptiness, yet there are almost always a few stray molecules of gas, sometimes in surprisingly complex chemical organization, per cubic kilometer. Any modern starship’s magnetogravitic shielding kept it from burning to an incandescent cinder and smoothed the way through what amounted to a galaxy-wide cluttering of hyperthin atmosphere. But the resistance of the gas was still appreciable through a reduction in the ship’s theoretical top speed.

The particular area the Falcon was then passing through seemed to be an exception. Bereft of the usual molecular drag, the Falcon was outdoing even her own legendary performance.

The captain pondered that, then addressed the intercom again. “Better back her off a few megaknots. I need more time than that before this confounded dingus comes off my arm."

“It is all but impenetrable. One cannot—what is your expression?—’starhop’ because one cannot see where one is going. It is said that attempting it in any case will cause one to burst into flame and vanish.”
Lando considered this. “Makes sense. No matter how diffuse the gas and dust is, translight speeds will create that kind of friction.

[Baffalo]

To get an idea of how much we're losing to friction due to impacts (whether directly against the ship or against a field generated by the ship) we're going to consider the impact of the interstellar medium on ships as they move through hyperspace. To do this, we're going to take some information and use it to compute a rough average of how much acceleration is needed to propel a ship at certain speeds. To do this, we're going to need some key information:

• The average density of interstellar medium: We will assume a Cold Neutral Medium (20 to 50 atoms/cm3) as an analog for a hyperlane.
  The speed of light, which we will average out to be 300x106 m/s for convenience.
  The front face area of the Millennium Falcon (compressed to a single, flat face for convenience): 25m x 7m (approx)
  The relative atomic mass of hydrogen (H1) at 1.00794u, with an Atomic Mass Unit of 1.66x10-27kg. Hydrogen will be used as an analog due to making up 75% of the universe.

First, we will compute the mass of the hydrogen in a given centimeter of interstellar space, with an average of 35 atoms/cm3. The approximate weight of a hydrogen atom is 1.00794 x 1.66x10-27 = 1.6732x10-27 kg. Given that there are approximately 35 atoms/cm3, that gives an approximate mass of 58.5613x10-27 kg/cm3, or 58.5613x10-21 kg/m3

Given how fast the ship is moving, the approximate number of atoms encountered per second will depend on the speed of the vessel, but with the approximate cross-sectional area of the Millennium Falcon and a depth of 300x106 m/s, this gives a volume of 25m x 7m x 300x106 = 52.5x109 m3.

So, if the Millennium Falcon encountered every atom in its way traveling at the speed of light every second, it would be continuously slamming into the equivalent mass of 3.07447x10-9 kg every second. Using the equation KE = 0.5(mass)(velocity)2, this yields KE=0.5(3.07447x10-9 kg)(300x106 m/s)2 = 138.351x106 Joules. To convert this to Newtons, we will divide it by 300x106 meters due to the energy being expended over that distance to equal 0.4612 Newtons.

Using calculations for the mass of the Millennium Falcon, we can estimate the mass to be approximately 1.5x106 kg. Since F=ma, 0.4612N = 1.5x106a, meaning a = 307.447x10-9 m/s2. This means that very little energy is actually needed to maintain the speed of light once the ship reaches it, assuming the hyperdrive is operational of course.

To calculate this for, say, 1000c, we must consider the change in volume of atoms. The equivalent mass is now 3.07447x10-6 kg, but the distance traveled is now 300x109 m. The kinetic energy becomes 138.351x1015 J, which means the equivalent force being applied to the Millennium Falcon is 461.1703x103 N. The new acceleration being applied to the Falcon is now 0.3074 m/s2. Again, this is for very thin interstellar medium.

To look at the same 1000c through much denser medium, such as nebulas and dense pockets of gas and dust, we will take the average for molecular clouds, with a density of 102 to 106 atoms/cm3, averaging 104 atoms/cm3. Running the numbers yields an equivalent mass/second of 878.42x10-6 kg, which is much greater than it was in our analog hyperlane. The acceleration needed to keep the Millennium Falcon moving is now 87.84 m/s2, or 8.96g.

In essence, like we would expect, the more friction due to the interstellar medium we have, the greater the acceleration is, and the more power is needed. So, once a starship like the Millennium Falcon encounters enough mass that the friction from individual atoms builds up to start opposing forward acceleration, what will eventually happen is that the ship is no longer accelerating and thus its forward velocity is maintained.

[PainRack]

Obi-Wan: Is it a fast ship?
Solo: You've never heard the Millenium Falcon?
Obi-Wan: Should I have?
Solo: It's the ship that made the kessel run in 12 parsecs. She's fast enough for you old man.

That's the context. How does it make any sense that he's refering to anything except speed? The discussion is explicitly about how fast the ship is.

The current retcon(or at least, it was ten years ago) is that the 12 parsecs refer to how close a Spaceship can go into the Maw and plot the shortest distance. The faster your ship, the closer you can go into the maw and thus, a shorter distance.


My model suggests a different interpretation. That its the ship ability to withstand higher gravitational forces closer to the Maw that accounts for this ability. And it should also translate to speed because it would mean the ship can make more drastic acceleration/decceleration along other journeys.


I'm just bouncing this off due to the disparity in speeds from Darth Maul TPM vs other examples such as Dark Force VSD, even though they have similar hyperdrives(ignoring the Zahn scale). One of the differences was the distance involved. The BTM CD, which allows you to transit faster from IIRC Aldeeraan to Tatooine if you make multiple jumps as opposed to a straightline jump was another disparity.


There's also.... nothing to prevent hyperspace lanes from being blazed more easily, if the problem was just common usuage and mapping of gravitational wells, and I dislike the regions of space which is faster, due to Darth Maul above exploit.

Its just a random thought since IIRC, it was the X-wing series by Stackpole which states that hyperspace was acceleration, and thus consumed relatively little fuel.

Its.... also just something that built upon my earlier model about how Interdictor cruisers interdict starships........

[Baffalo]

Let's run with this theory

Ok, let's assume the largest theoretical black hole, which sits at 10AU in radius with a mass of 109 Msun, or 20x1039 kg.

The mass of the Millennium Falcon is established as 1.5x106 kg. Converting 12 parsecs to kilometers yields 370.8x109 km. Subtracting 10AU (1.496x109) from this yields 369.3x109 km.

The force of gravity on the Millennium Falcon from this distance is computed as M1 x M2 / Distance. So, (20x1039 kg)(1.5x106 kg)/369.3x109 kg = 81.234x1036 N.

The acceleration, thus, is going to be a = m/F = 1.5x106 kg / 81.234x1036 N = 18.465x10-30 m/s2. So the force at a distance of 12 parsecs is negligible in the grand scheme of things.

[PainRack]

Except the distance of 12 parsecs in the Kessel Run isn't measured by how close you run to the black holes:D

[Batman]

Indeed. We're also not talking about one of them, but a whole damn cluster. And as PainRack already eplained, the current (as far as I know) retcon is the 12 parsecs are the distance Han had to travel for all of the Kessel run by getting [/i]closer[/i] to the black holes than anyboy else (something tells me the math on this still doesn't really work out, but then, the chances of you running into someting in a blind jump in average interstellar space are infinitesimal to, so...)
I don't know why they ever bothered with the retcon to begin with. 'Han is trying to impress cluesless farmboy who dissed his ride via technobabble he didn't expect the boy to understand' always worked for me.

[Baffalo]

Ah, forgive me then. It's been a while since I had anything to do with the Maw, not since I made it in 11 parsecs

(That was a lie, I only made it in 12.1 parsecs )

[Batman]

That's okay, I never made the Kessel run at all
Well not that I can remember at any rate.

[PayBack]

I realise the explanation of the Kessel run was to account for using a distance when talking about time.. but another option (yes yes it might conflict with a million other things but I'm replying from work so shouldn't even be here at all

If Hyperdrive folded space to a degree, then doing the Kessel run in 12 parsecs would be impressive if it folded it that short, when in fact it was 12000 parsecs, and most other hyperdrives could only fold it down to 30 parsecs.

Oops boss is coming....

[Baffalo]

Hyperdrives do warp space to some degree because we see the stars seem to spin a bit after a ship enters hyperdrive. The degree to which it does this, however, is unknown.