Bill Phil

Interesting. Looks neat. Maybe it’d be good for Halloween? A giant space pumpkin?

Slaughterhouse Five is all about the bombing of Dresden and the psychological effect of the bombing on a WWII vet. I only mention it cause aliens show up - but it’s debatable if these aliens are real or just a figment of the main character’s imagination.

Is that Orion TWR for the propulsion system alone or the entire vehicle?

Alright I put together a model in MATLAB. (I already had a similar one lying around, didn't take much to modify it) (Hopefully this works) Imgur album with plots: https://imgur.com/a/xMHwucs Assuming a cylindrical planet can be modeled as a line of discrete particles. Used an RK4 integrator with a step size of 60 seconds. Number of particles is 100. Each with about 1/100 the mass of Earth. Looks like it acts like mass concentrations around the poles.

Well, not necessarily. Around a finite cylinder the moon would still experience a gravitational force toward the cylinder even past the ends. In the case of our Moon, it's so far away from the Earth and the Earth is very small compared to that distance - so the real difference is likely insignificant to the Moon's orbit, or at most only perturbs it slightly.

Well the truth is we can’t treat real planets as spherical - they’re not. Terms like the J2 term are used to describe unequal mass and geometrical distributions as alterations to the point mass model. The J2 term specifically models a planet’s oblateness - which gives rise to precession of the ascending node. The ISS’s orbit precesses around 5 degrees a day (roughly 16 orbits) as a result. Precession around Jupiter or Saturn would be even more extreme. I suspect you could model the cylinder as a line of discrete points - perhaps the gravitational field could be calculated analytically using calculus though I can’t say for sure. Then integrating with a runge-kutta or symplectic integrator would let you see how that changes trajectories. Actually, I might do that myself...

Depends on the specific impulse and mass ratio, as well as the trajectory flown. For a decent variant a moon of Saturn and back isn't that far fetched, provided the payload isn't too massive or you're willing to sacrifice acceleration. For an antimatter vehicle, anywhere is possible - provided you have the mass ratio.

Actually I believe we do use relativistic corrections for certain trajectories provided the need is present. With low enough masses and velocities the differences are small enough to be ignored. A satellite will retain its orientation/rotation relative to the “fixed stars” (which aren’t fixed but we say they are when it’s convenient) or the frame of reference unless acted upon by a torque or other influence. I believe this is the case whether or not you use Newtonian physics or GR. Gravity can apply torque though to large enough objects.

Play Kerbal Space Program. Read papers about space exploration/travel. There are loads on NASA ntrs.

In recent memory? Probably my abscess tooth from last year. Man that thing hurt. Couldn’t sleep. Though the nerve was dead by the time I got the root canal procedure - so that didn’t hurt too much. Besides that my big toe once hurt so bad I thought I had broken it. I got lucky though, it wasn’t broken.

Yeah they're still developing it. Just can't do all the work they need to.

Hung out with friends over discord. Man I needed that.

Blue Origin is the prime contractor for one of the Artemis lander proposals (they will provide the descent stage and work with other contractors to integrate the ascent and transfer elements). But their current design is too heavy to throw to TLI/NRHO with the desired margins. The schedule also keeps slipping, as it always does.

Like hardware for Z-pinch and a magnetic nozzle. If it's advanced enough it can look like just about anything though. So it could be a normal propulsion system. It also seems to perform better than Orion generally - 16000 to 20000 seconds of specific impulse for the original Mini-Mag concepts compared to around 4 to 10000 for the original Orion concepts. Using boosted fission pulse units Mini-Mag Orion can likely have over 30000 seconds of specific impulse since it would have a higher burnup rate of the fission fuel. That means that, assuming a mass ratio of around 2.7, a Mini-Mag Orion could easily have 200 km/s of delta-v. Then it can easily get to just about any target in the solar system. Fast transfers to inner planets are possible, and 1 AU per month is about 62 km/s, so a fast transfer to Jupiter would be easy for Mini-Mag Orion (New Horizons arrived a little over a year after launch, so it's possible). If you use antimatter then you can make something way better. As for its appearance... it can look like a rocket. I think it needs radiators for its reactors though.

So apparently the BO lander concept is too heavy at the moment and SLS isn't launching until 2022. Yay...