Hyperspace Exclusion Zone
(Copied straight from .XML 'backup' file, needs formatting and corrections. ZM User (talk) 20:15, 22 April 2024 (PDT))
 : : A Hyperspace Exclusion Zone or "HEZ" is the volume surrounding a gravity well where an FTL drive will not work. : Forcing one to _try_ to work inside an HEZ leads to Bad Things happening to everything inside the drive field. : To avoid this, the Confederacy has developed mass-sensors that allow navigation in hyperspace, but they involve so much computation that only an AI can do it in realtime. : The Sa'arm use much the same drive system as the Confederacy, but lacking AIs they can only use the drive for pre-calculated jumps with no in-voyage navigation.
Hyperspace and drives
Hyperdrive usually protects the ship running it from anything natural -- you just aren't there, unless the object in question is small and VERY massive and collapses the field. The Aurora was probably loafing along quite slowly for a hyperdrive ship and was unlucky enough to cross fields with a VERY small black hole -- an amazing accident. Another, more plausible explanation, would be collision with another ship -- since the Aurora wasn't annihilated, that argues for two objects of relatively the same mass operating within normal physical laws in the same bubble universe... IF you can directly chase a vessel in hyperdrive and IF you can extend your field to intersect it's field, you can deploy weapons in combat, working inside the bubble of your shared miniature universe -- but it's difficult to impossible, usually, to make such a thing happen. The Sa'arm have hyperdrive, but it's primitive; it takes a Hive ship to move anything at ten percent of what Confederacy ships are capable of, which gives us the advantage of manuever in open space and even the kind of chase capability I just described, since Sa'arm communications couriers only move at 5% of what a Confederacy frigate can boast. Detection is the worst part of the equation, as a ship in hyperspace doesn't leave any traces in normal space to follow after the initial passage disruption, which heals rapidly.
Pushing the Zone - Hyperspace cannot be entered or left too close to a large mass, probably due to some gravity-well issue that humans don't understand yet. Attempting this anyway leads to broken ships. During a discussion in 11/2013 on whether this could be weaponized got an opinion from The Thinking Horndog that you cannot jump too close to a well, but you can destroy your drive trying. Similarly, if you pop back in too close you will return to normal space but without important pieces to your drive. In both cases the ship mounting the drive can expect damage due to forces we don't understand being upset that we tried to violate basic cosmological principles. It was proposed that you could damage the well if the ship was more massive than the well, but with current technology this is impractical. It follows that if you return to normal space and that space is occupied by a smaller mass than the ship, perhaps a stray asteroid or dust mote, the asteroid 'goes away' and everything inside the hyperspace bubble (ie, the ship) is protected. The volume that we cannot enter has been labeled the Hyperspace Exclusion Zone or HEZ.
Discussion
[Originates from another page, so context is awkward]
ZM 6/23/2014: This page, according to the edit history, has not been substantively modified since it was created in 2009. As of 2014, we have some issues with the numbers. It gives a terrestrial planet's HEZ as ending 240,000 miles out. That would be fine, except that we have established that, in order for some popular and well-accepted stories to work, transporters must have at least a 300,000 mile range. Other published and accepted stories have, as major parts of the plot, the necessity for a ship to come out of hyperspace and drive through normal space for a while before reaching transporter range.
It follows that the 240 number must be greater than the 300 number, and we can't change the 300 number. Therefore, until the writers' list gets this argued out, I'm assuming we just dropped a decimal point someplace and really meant "2,400,000 miles". As always, this will be worked out on the list and I'll update this page when all the dust has settled.
ZM 1/26/2015: Okay, the Swarm email list has been down for 4 days now so I'll put my notes here. What I finally came up with used that 240,000 mile figure -actually 385,000 kilometers- but used it as in "The HEZ limit is 385,000 kilometers from here" where the speaker is in an Aurora at the Earth-Moon L2 position. In other words, the HEZ limit is 385,000 Km out from L2. That gave me an HEZ for Earth (and Moon) of 830,000 Km. This is far enough out to work for the older stories.
From there I could work the formula I had backwards to derive the 'Hyperspace Exclusion Constant' the same way that the Gravitational Constant was derived, and then run the formula forwards for each body (Sun, Jupiter, etc) and see what I got. I tried a bunch of different formulas before I realized that the basic problem was that squaring the distance as for gravity always gave an HEZ that was far too large. I mean, using the formula for gravity gave the Sun an HEZ that was out in the belt somewhere, so that Earth and Mars were both in the Sun's HEZ. That won't work for us.
I was going to use a 3rd order formula with distance cubed, but I couldn't find a cube-root formula in the spreadsheet program I was using (LibreOffice Calc). Also, I wanted the body's size in there somewhere, because a red giant should have a larger HEZ than a black hole of the same mass. Actually, that black hole should have a _tiny_ HEZ. There's already one Swarm story about that, 'The Chuck Hole'.
So, I made it 4th order, and when it was time to reduce it I used SQRT(SQRT(f)) which gives you the 4th root. And used the Moon's orbital radius as the 'size' factor, since double planets have huge and erratically changing HEZs. That gave Earth+Moon a large HEZ compared to normal planets, and everyone else had a reasonable HEZ. The Sun's HEZ is still out past Mercury's orbit, but who cares?
The spreadsheet with my calculations, ready to be used for anyone else's system, is on Dropbox and available from ZM at TampaAD.net.
(Someday this will be a navigation template. It will provide a bar across the bottom of each article with useful navigation links. Until then, this is just a placeholder to get rid of all the red "broken link" indicators. -ZM User (talk) 10:00, 3 May 2024 (PDT))
