Science Forums 2

[CraigD]

Originally Posted by TheBigDog

It has to do with the module rotations to smooth out accelleration and the weights in the spokes to adjust the orientation of the ship without despin. I would like to open up the question of how to do this again.

My first thought is to have large flywheels inboard of the main ring that can be manipulated to adjust the orientation without having to despin. If we are constantly despinning and respinning we will quickly go through our supply of propellant. Any thoughts?

My first thought is that the inside of the spokes is an ineffective place for a system to change the ring’s (and thus, the whole vehicle’s) orientation.

To change the attitude of a gyroscope – or anything something with significant angular momentum – torque must be applied in a direction perpendicular to the angular momentum vector. Applying it in a parallel direction won’t effect attitude at all.

Since gyroscopes translate torque into angular velocity (precisely according to the vector formula , a gyroscope with a lot of angular momentum like the Prophesy will require a lot of torque. Other than the simple quirk that the resulting angular velocity is exactly perpendicular to both the torque and the angular momentum, such maneuvers are easy to calculate. Since , the further whatever supplies the force is from the rings in the ship's fore-or-aft direction, the less the force, and consequently, the energy required for a maneuver.

As a rocket, producing force is among the things Prophesy is designed to do best. It’s designed mainly to apply that force parallel to the rings’ angular momenta, but I can imagine a fairly simple enhancement to its “thrust management” (shock-absorber) system that would allow the main atomic motor to provide ample attitude-changing thrust: allow it to handle slightly eccentric thrust.

Although the most straight-forward approach to this would be a mechanical joint connecting the blast-side parts of the system to be moved independently of the rest of the ship, I suspect that a better solution would be to allow the shock absorber to move along 2 axes rather than 1. This would be particularly easy if the shock absorber is electromagnetic, like the one used in the ”Dropzone” amusement park ride. The pellet-injecting/detonating system need only detonate pellets slightly off-center to effect an attitude change.