Steel

Not sure if that's a problem really

Doesn't really mean much. Anyone with a computer can make a CAD model.

No.

I'd argue very much contrary to that. If the we found life elsewhere and it could be said with reasonable certainty that it and we didn't have some common source, then the statistics suggest that life (maybe only up to microbial level but who knows) should be fairly abundant - if it occurs at least twice in the same solar system from different sources, then it's likely that it would be happening in many other solar systems. The question then becomes about why, if there should be a lot of microbial life in the universe, why have we seen no signs of higher intelligence, hence the "great filter".

Exactly, but what K^2 was saying (or at least what I interpreted) was that the discovery of any life in our solar system changes our view on the Fermi Paradox, because it eliminates one of the biggest historical "great filter points". Thus, it means that the "great filter" is more likely to be ahead of us, which is bad news for us as a species.

You're misunderstanding the Fermi Paradox. It's not just about whether or not there is life, but why we don't see more of it if it exists. One of the main solutions is to posit a "great filter" (as mentioned earlier by K^2) which is a point in the evolution of life where the vast majority of life forms that come into being don't get past. If we find life on Titan, we at least know that the great filter isn't simple getting life started in the first place, which means that its more likely that the great filter is ahead of us. There's a waitbutwhy article that's really good if you want to read more about the great filter

This article has a good bit at the beginning about progress that might interest some people. On a side note, this and the part 2 article are really interesting take on the future of AI, which is one of the areas that we are likely to use in some way to define our progress over the coming decades.

That's exactly how it does work!

What sort of physical situation exactly is it that you want to picture?

There is a particular velocity that accounts for an altitude, but only for circular orbits, due to the balance of the forces. The closer you are, the stronger the gravitational force and so the stronger the centripetal force has to be to balance it, hence a greater velocity.

Yeah, going back to gravity. You weren't wrong when you talked about gravity changing. It to do with the fact that at higher altitudes, the force needed to balance gravity gets less and less, and since centripetal force depends mainly on velocity squared, it means that the velocity in a circular orbit lower the higher you go.

Yes I did, I've edited the post so I don't look like so much of an idiot!

There's actually very little difference in the force of gravity at that height, even to the force on the ground. It's to do with the fact that in circular motion, the further you are from the centre point of the rotation, the slower you can go and still stay there. You can see for yourself if you calculate the difference in circular orbital velocity at 90 km and at 110 km and compare those to the number for 100 km. That will show you the effect of being further away or closer, despite the fact that the gravitational force is almost exactly the same.

Because in the first example you're moving at the right velocity for that orbit at the correct height. In an elliptical orbit you'd be going at that speed, but you wouldn't be at 100km, so you'd climb/fall depending on whether the speed at that point was above or below the speed for a circular orbit at that altitude. Hope that makes sense!

Ah ok, I see. I would imagine that the reason is that the FH wasn't designed from the ground up to be recoverable. Most likely it was more of a "Hey, our heavy lifter design could also use some of the reusability that we've managed to get to work on the F9!". With this generation of it's rockets i feel that SpaceX want to get the basics right (i.e. being a successful lifter) and then extend that program to begin to field test recovery and reusability elements. Then maybe in the next generation the whole lift system can be designed with reusability in mind from the ground up.

I'm not sure I understand your argument for using SRBs on the second stage, what are you trying to achieve here?

That's some really nice work! I might have a play around in the code if I have time

Well to start you're going to be looking at differential equations and - unless I'm wrong - ones that can't be solved analytically once you start looking at motion in two or three dimensions including drag and such

Exactly my thoughts! I'm sure at some point someone thought that we'd never be able to travel any quicker because trains were almost as fast as they could get, then... BAM, the aeroplane is born (I'm sure it went something like that anyway) To put it another way, if we still measured progress by how good our steam engines had gotten, we wouldn't have progressed much in the past century or so

Launch coverage begins in 11 (6 now) minutes, the launch is in about half an hour

We've seen nothing observationally AFAIK that suggests that dark matter does not have mass in the same way normal matter does. I totally agree that it's very dangerous to assume that your current paradigs will be sufficient to explain everything. Equally I think there's no need try to overcomplicate things (which is a big problem in many areas of theoretical physics) by creating new theories and paradigms to explain anything unknown before we've ruled out current ones.

My guess (if its quite a small acceleration) would be that flex in the structure of the craft is causing the engines not to fire in exact opposite directions in this case.

Not true, the net force on the craft will accelerate it linearly, the net torque due to that force not acting through the centre of mass will cause it to rotate.

Because the engine is still accelerating the craft at 0.24g (the net force on the craft is still the same regardless of where the engine is pointing), its just that because you aren't thrusting through the centre of mass that it causes the craft to spin as well

I see where you're coming from. Granted we don't know enough about it's make-up to know many things about it, but the one thing we do know with at least some degree of certainty is that what we call "dark matter" appears to have mass and thus interacts gravitationally with what we call "normal matter". From this we can infer "where" this dark matter is concentrated by looking for it's gravitational signatures i.e. gravitational lensing, galaxy rotation curves and so on. So long as we have evidence that this is in fact a gravitational attraction (which almost all observational evidence does point to AFAIK) and not some other unknown force (which I would find surprising considering how close the properties of the observed effects are to gravity), then we can actually reasonably localise, with an error, dark matter clusters (clumps, regions of high concentration, whatever your chosen phrase).