The idea here is to create a warp drive which allows adventurers to travel the stars, putting space travel in the reach not of any yokel in an RV, nor only of billionaires and governments, but anyone who can afford a flash fishing boat or small yacht or aircraft. So I designed it in such a way that if you can get yourself 48km up airtight, then you can get to the planets and the stars. I wanted it to have dangers, but not to act as a bomb (any time you come up with supertech in an rpg, geeks start talking about how to blow stuff up with it.) My thoughts are below.

A warp drive forms a warp “bubble” around a craft. From and to this bubble nothing can travel, and it acts as a frame of reference for the craft. All that's visible of it along the edges inside and out is the glow of atoms striking it and becoming plasma. The warp bubble can be shaped from within, and when one side is flattened, it rolls forwards at superluminal speed – 1191 times light speed, in fact, or 1parsec per day. During this time, those inside the bubble feel acceleration opposite to the direction of travel of 8.5msec-2, almost Earth-gravity.

The warp drive itself is small, and can be built with $5,000 worth of components. However, it requires high temperature superconductors and cooling with liquid nitrogen, so that fixing it is time-consuming, and its parts are not easily replaceable.

Activating it takes energy, Ea,  proportional to the area of the warp bubble, and the mass contained within. The longer the warp bubble takes to form, the larger its internal area. In practice, a large internal area is bad because it's more difficult to keep stable; a small internal area bad because its edges are “thinner”.

Ea = 4πr2m/t2. It might seem that it would be good to take a long time to form the warp bubble to save energy, but as noted above, this will be more difficult to maintain, and the optimum time is a second.

The bubble's surface reacts to the universe around it. No energy or matter can pass through it, but space-time curvature will curve the bubble surface. The warp drive can adjust to this, but not too quickly. In practice, the warp drive can adjust to a ny decline of local gravity forces, but no more than 1ms-2  increase. So for example a craft could enter warp while in orbit around Earth, but if returning to Earth in warp, could not come closer than 335km. Attempting to come closer leads to bubble collapse, as below.

As noted, matter touching the surface of the warp bubble turns to plasma. This destabilises the bubble causing it to collapse, and implode on the craft. This means that a craft cannot safely create a warp bubble in atmospheres denser than 0.1% of earth's atmosphere, that is 100Pa or 0.015lbs/in2.

The implosion will utterly destroy the craft, and render it into fragments.

The craft retains its relative velocity, and when arriving at the target must have its own means of catching up to or slowing down there. For example, a craft warps from 500km above Earth to 500km above Mars when the two are in conjunction; Earth has an orbital velocity of 30km/sec, and Mars 24km/sec. So the craft will be travelling 6km/sec relative to Mars. Orbital speed at that altitude is 3km/sec, so the craft must lose 3km/sec of speed.  

In practice, then, craft wanting to warp will launch to a level of low atmosphere (100Pa is found at 48km altitude on Earth), “aim” the craft, form the warp bubble, travel to their destination, dissolve the warp bubble, orient themselves, form another warp bubble and travel, and so on, until they reach an altitude of some few thousand kilometres above their target. If they have little relative velocity, they'll then let themselves fall, form another warp bubble to go backwards and fall again, until they have enough relative velocity; if too much, they'll do the same but with aerobraking and/or simply bleeding off speed.

Thoughts?

Traveling blind?
You're going to lose a lot of ships to poor aim or unexpected obstacles.

Quote from: Cerulean LionTraveling blind?
You're going to lose a lot of ships to poor aim or unexpected obstacles.

One could make the same argument against any vessel travelling at very high speeds. No time to brake if something appears in your way (not even time to notice something in your way). No way to detect tiny obstacles that effectively become extremely high velocity projectiles when you slam into them.

Even dust could tear you to pieces.

Perhaps some kind of quantum effect occurs at the boundary of the bubble that can take account for isolated small obstacles, but that still fails in atmospheres denser than 0.1% of Earth's.

- Q

Certainly many craft would end up destroyed due to poor aim. Likewise, in the days of the age of sail, many craft were lost at sea due to poor navigation, bad weather and so on.

Unexected obstacles are not likely to be struck. Space is big. It just seems to us there's a lot of matter because we're standing on a planet. If you just head off in a random direction, you're very very unlikely to strike anything substantial at all. The collisions will occur when you were aiming for something, but went too close - poor aim. That's as in sailing, if someone is coming to a landfall for the first time, and has no map of the sea around it, and doesn't take the trouble to fathom the depths, he may end up beached, or even breached upon a reef. That would be called "being a poor navigator." It's only right that poor navigators should crash

Quote from: Kyle AaronCertainly many craft would end up destroyed due to poor aim. Likewise, in the days of the age of sail, many craft were lost at sea due to poor navigation, bad weather and so on.

Why do I think this calls for an original Classic Traveller-type character lifepath system where you can die during character creation...