Hi,
Actually with an antigravity drive you don't need shields. Considering that you're actually falling away from a large gravitational field and not trying to push yourself away with something like a rocket, mass isn't an issue. So why not have a hull three feet thick and made of solid titanium etc. That should do fairly well for defense
Cheers, Greg.
You're going to need enough energy for the MVsquared. So a massive ship will need huge power reserves for any major delta vee (Change in velocity is change in direction as well as change in speed). Like the output of a small star. As most of trip is cruising I would suggest running hydrogen fusion generators at full whack all the voyage, and making antimatter and storing it for sudden peak loads (storing antimatter, ugh). If you ever end up with too much antimatter you can always propel it against your enemies – or it makes a great firework display in a gas giant's atmosphere.
The only draw back so far is the lack of shields, not a problem in a normal ship but I need a fighting ship for an ending with some drama. I think an Ion drive can give you a forward pointing shield against space dust, but all I have so far is a wobbly bubble that can be used to fix teeth (I know, I'm demanding).
Hi Chris,
As I understand it you want to use internally generated gravitational fields to compensate against inertial forces?
Well, no. Actually, my drive reshapes the gravitational field from spherical to ellipsoid; like a reflector sending the light of an omnidirectional lightbulb all one way, in a beam. So everything in the ship is undergoing the same forces, all moving together, and the only inertial forces are tidal (negligible except for a very tight turn round a small, dense object, or the elastic cable when it rendez-vouses with supplies. I put in the inertial correction for ships where the motors push against the chassis, and that pushes the occupants. My hypothesis that if you know how to control gravity well enough to drive the ship with it, you know how to protect the occupants.
As I see it if you could precisely - and I mean precisely - balance the artificial gravitational field against the inertial forces it could work for everything inside the ship. But what about the hull? That has its own inertial limits. And if you could then balance that too against the inertial fields by generating a precise artificial gravity field that extends beyond the borders of the ship, you're actually on to building half a space drive through your artificial gravity inertial compensation system. All you have to do is make it negative - i.e. antigravity, and space travel is possible. And with an antigravity drive you don't need inertial dampening - save for cornering of course.
Gravity, unlike magnetism and electrostatic force, has never shown any signs of symmetry. It attracts, but does no equivalent repulsion. It could well be it is incapable of repulsion, just greater or lesser quantities of attraction. In which case you are banning us from space? We've made a decent start on things with nothing but chemical energy; anything added to our arsenal can only be positive.
My ship could never take off from a planet on its drive (ignoring the fact that it's as big as India; where would you land it?), but theoretically, if the drive were capable of elongating the gravitational field enough, anywhere but the poles it would be flung off by the Earth's rotation. Actually it goes to a space station at the top of an orbital tower. So it has an orbital velocity around Earth, added to Earth's orbit round the sun; with no power, stable. At the right point going round Earth, it activates its drive directly into the sun, and misses, gaining kilometres per second of speed, like a comet. As it rounds the sun, we switch the direction of pull, so the sun's gravity affects it a whole lot less (so, unlike a comet we keep most of the speed) and aim for, say, Jupiter, and do yet another slingshot manoeuvre, gaining more kinetic energy, then back to the sun… All positive gravity and sure, it takes a while. If you're going to be a century in transit, accept a couple of years building up speed with connection to the Internet and the latest episodes of 'Eastenders'.
As I see it an antigravity drive would actually be the only possible drive that would allow space travel. (Well a warp drive system too perhaps).
I assume for 'space travel' read 'star travel?'
Consider that if you want to accelerate to light speed to get anywhere in a reasonable time that at one g it will take over a year. But then instead if you have antigravity and can presumably amp it up you can accelerate to a hundred or a thousand g's. All you have to do is get close to the sun, turn on the antigrav, and accelerate away from it in the right direction at say a thousand g's and actually the ship and everything in it is effectively weightless. You aren't accelerating in the same way as if a rocket's pushing you. You're falling away from the sun. And everything inside the antigravity field is falling with you.
So it would seem silly to me to have an inertial compensation system based on artificial gravity and not have a true antigravity drive.
Cheers, Greg.
The only book that I can think of, off hand, where this kind of propulsion is used is Earth by David Brin, and then only in a localized manner around Earth. (A black hole falls into the center of the Earth and they use it to essentially power propulsion in the vicinity of Earth).
Piers Anthony in his 'Bio of a space tyrant' series (lousy series, but who ever said you couldn't pinch good ideas from bad realisations?) uses 'gravity lenses' which are largely the same idea. Most people assume that if gravity is conquered, control of it is absolute.
You might be able to have a more 'dog fightery' style in a relatively densely packed area of space, say the Jovian system, ships bouncing around the moons.
I haven't given much thought to the dogfight possibilities (with something the size of mine it might well be 'ships bouncing the moons around'. Which is impolite, and inconvenient to anybeing inhabiting said moons.) But just changing speed in a battle where everything should be predictable could mess up your opponent's targeting considerably; think light minutes of distance, and kilometres per second of speed (in curves)
If you want some good examples of Newtonian physics being built into a space battle, look up David Webers Harrington series.
But Weber generates gravity shear planes, in wedges, which interact directly with some non-Einstinian space framework (You might be able to find a discussion between him and myself as to whether inertial compensators are necessary, since what is being accelerated is the space in which the ship is contained, so there is no resultant force on the occupants (a discussion he won by the somewhat unfair argument, that I could not counter, 'This is my universe and it works like I say it does.'
These shear planes also act as shields, as the gravity gradient is sufficient to disrupt anything incoming; a laser beam will go through it, but it'll lose coherence and come out a simple beam of light, unfocused and just about harmless.
So... I'm looking for a spaceship that has gravity flux engines for my super advanced aliens. No thrusters here, no ejecting of useful mass out one end to get moving in the other direction - just whizzing about by pushing and pulling on the nearest centre of gravity. Very useful when that just happens to be a really big Gas Giant. So my scary (in a nice way) friend, can I have my Gravity Flux Engines?
