Recent content by BLANDCorporatio

Indeed, it's puzzling why this is puzzling. No offense. Maybe I don't understand what the problem is. But here's what I think I understand. You know the center of the hexagon, hence you know the center of the rectangle (because they coincide). Let this point be (hx, hy). If the rectangle is...

That looks right.

The wiki article on torque should give you all necessary info. Torque (in 3D) is the cross product of the position vector with the force vector. Assuming then that the position vector of the thruster (relative to the center of mass) is {rx, ry, rz}, and the force of the thruster is {fx, fy...

The general answer is there is no general answer. You have two numbers. Somehow, you want to crunch them into a single figure of merit. Some information will be lost (let's not get into ways to fill planes with a curve now they're not relevant ;)). You might prioritize one figure of merit over...

I made a mistake when listing the Verlet formulas, so that's my bad. They should be x[0] given (initial condition) x[1] = x[0] + v[0]*h + 0.5*a[0]*h*h (from initial conditions, find the very next position) and thereafter use x[k] = 2*x[k-1] - x[k-2] + a[k-1]*h*h so no 0.5 factor on...

Yes, this is true. RK4 requires you to compute forces along a few points of an 'estimated' trajectory. But those points you can already compute from previous stages of the RK4, so all's fine. HOWEVER, if you want a 'more accurate than explicit Euler' integration scheme for your program, I would...

Interesting questions again. I won't quote from the post but I'll try to address them. 1) SO3 and its representations. There was a question in a mechanics text-book: 'what is SO3? is it S1*S1*S1 (similar to but not quite Euler angles)? is it S2*S1 (axis-angle)? S3 (unit quaternions)? or...

Cool stuff. I'll try to give a few comments on each. (Assumptions: Newtonian gravity; no upper limit on velocity; object around which the orbits are defined is a point-mass object at the origin which is also a ghost that one can pass through) 1) Yes, that is correct. (For anyone else watching...

:rolleyes: Aww come on, we're going to argue semantics when it was clear what everyone meant?

This is fascinating, but Thorsten, what equation would you use to compute deltaV based on exhaust velocity, mass ratio, and whatever other parameters needed? Since that's a bit ill-defined, some more specific scenarios. Ship A is happy with always having a velocity less than, say, 0.2c in the...

The magsail/parachute for breaking seems like a good idea. How about having an outside propeller (like the laser battery thing in the Avatar ext. universe), and magsail brake then? Bussard ramjets seem to have a maximum velocity to them that's quite a bit less than 0.6c. When I first...

irt. Fyzik: Thanks, that's a more elegant way to calculate it than what I had in mind. (Use the relativistic rocket equation to compute the mass ratio for 0.6c then square the result for braking). I don't have a 'feel' for rapidities yet, but I should get one. ---------- Post added at 10:58 AM...

This is certainly true. I kept things simple, because they look bad already even with the classical rocket equation (and said, eh, at 0.6c the mass is 1.25 times the rest mass; tolerable ;) ). The relativistic rocket equation (which yes, is more accurate here) produces results that are more...

Cutting the ship's weight is good, it means overall there's less payload to lug around. But the problem with the mass ratio remains. You aren't escaping the rocket equation just by making the rocket out of super-cardboard. If its mass ratio needs to be 10, then it needs to be 10, meaning you...

Infidel :P Black holes are the future.