Advent Day 2 - Mint Choc Space Station Shuttles

Advent Day 2 !

And a sketchy sketchy of a space station. But first ... What's behind the doors ?

We have a Mint Choc Chip marshmallow, which was delicious and is making me want to order some online right now. Here you go - a link ! (Not Sponsored) That temptation is a very tempting temptation.

Oh and there's Kylo Ren's Command Shuttle there as well, a very mean looking craft when it appears on screen. Bigger than your average shuttle to be sure and well armed as well.

Elite theme of the day is Stations and I have a few of those to have a natter about. Let's start with a loose sketch :

I'll get to some more later but that's my thought. The designs of space stations are heavily wrapped up in gravity and how you deal with that, how you use it, how you are bound by it and how the physics of the universe interact with the components. So what we have there is a station with concentric rings, with a pair of modules on the spindle in the middle.

This is a spin gravity station, where the whole thing depends on varying levels of centripetal force. That is, it is bound by Newton's 3 Laws :
1 - An object in motion will remain in motion unless an external force acts on it.
If you whack a puck across ice, it'll keep going ... only slowing due to the friction forces acting on it.
2 - Force equals mass times acceleration
We'll come back to that one later. It rules the Weight equation.
3 - For every action, there is an equal an opposite reaction.
If you catch a cricket ball, then your hand exerts a force stopping the ball and the ball exerts a force on your hand.

So with space stations with spin gravity, every object will head off in a line straight in to space ... unless something exerts a force. The outer side of each ring becomes the floor and exerts a force on everything on it, which replicates gravity. The greater diameter of the circle, the more linear velocity and the more force exerted to accelerate objects around in the circle.

Aside - gravity is a different type of force where heavy stuff exerts a force on other stuff with mass. However, it takes a lot of mass (like a planet) to make it have any significant force to stop things flying off it in to space. That kind of mass isn't practical to put in to a space station and might well attract the planet your station is orbiting or at the least, affect its weather like our Moon (with 1/6 G) affects our tides.

What it means for Stuff On Your Station is :
Things towards the centre have low gravity. Rings towards the outsides have higher gravity.

Everything we do depends more or less on gravity. Our bodies degrade in low and micro gravity, while industrial processes can work better without the influence of gravity. It's all much of a muchness there. The Expanse covers the medical side of this extremely well. Low gravity medicine is good for relieving the stress on the body ... however zero gravity is critically bad for injured parties because our bodies depend on our circulation system being able to pump fluid around and generally remove the Bad Stuff.

There's a lot more to it than that and that's without going into things like Fission Power, where our nuclear reactors mostly depend on a hot/cold convection circle that needs gravity to operate.

Enough science ? One more thing ...

Weight and gravity aren't all of the story. Everything has mass. (Weight is Mass times Gravitational Acceleration - see Newton's 2nd Law). One thing I think the Elite stations are missing is warehousing for cargo ... this is moved best in microgravity. The cargo still has mass and inertia ... but a person who could move 1 tonne (slowly) in zero gravity would have minimal chance of lifting it even in 0.1g (100kg).

Gravity is the key to everything. Shall we look at some stations ? Here goes !

That's a Coriolis fly by in Elite, with the Needs More Pew Pew Cobra Mk4. This is a tribute back to the original game, which was heavily into geometric wireframe shapes. There is a "trench" around the face with the docking envelope on these stations that I'll try to fly around at some point. One issue with these stations is that because they have flat sides, the Coriolis Effect kicks in. Unless you're in the centre of a face, Up from the floor is not necessarily Up as spin gravity would have it ... Which would have some nasty effects on your balance !

There's an Elite station from a little while ago. Bit damaged but a nice example of a spin gravity station. One issue I have with these is the legs that go to the outsides, why are they bent ? Plus there isn't usually too much outside the spine that connects everything together, so transit up and down the station is always in changing gravitational conditions. I.e. no spin gravity, just acceleration from the transit cart stopping and starting meaning that the floor and roof interchange.

Elite also has Outposts, which are essentially modules welded together with no main docking bay. These make sense with the other type of gravity - technological gravity. Grav plating in the floor of the type Star Trek and most other scifi like to use.

Moving swiftly on from that one :-D. Gravity makes absolutely no sense on that.

There's an awesome space station. It's Babylon 5 and this one uses spin gravity where that makes sense ... and grav plate cheating for where it's convenient for the story.

This one has a central cylinder with the habitation decks inside and a fantastic park / passive oxygen generation in the cylinder as well. This even becomes a plot point as a character leaps out of a transit cart to avoid a bomb, to realise that when he reaches the other side of the cylinder, it's going to hurt a lot. The spin gravity turns people around as well, so if you're going 50m/s right at the top, you're going 50m/s left at the bottom. If you take a short cut across the middle, you'll hit the bottom at 100m/s. OUCH.

The docking bay is at the top on this station, between the forks. The ships are then moved around to their berths, which is only shown a couple of times in the series. The curious thing is how Stuff is moved from the zero g docking bay sections to the sections in spin gravity. Newton's Third Law will also make the stationary part tend to spin.

Actually that's another thing - there is a gyroscopic effect as well, aka precession. A force on one side of the rotating wheel will make the wheel turn in another direction. Mixing spinning things with stationary things can mean awkwardness. (Which you'd manage with thrusters and reaction wheels).

One more station ? Here's an iconic one :

As space stations go, this one is particularly good. It's a technological gravity station, which means it doesn't need to spin at all.

One issue with spinning stations is that the really big ships will be limited. They'll have to stay outside and use shuttles to transfer people and cargo around. With Deep Space Nine, the big ships can dock up to the pylons with other ships connecting to the outer docking ring which also has the warehousing facilities.

It's a lovely station and makes a great setting for a Star Trek show that consistently delivered massively high quality. And we hadn't seen much like it before.

That's one thing that keeps me flying around the Elite universe, all of the variation ! Difference is good.

More tomorrow. Dunno if I'll be drawing a Cobra Mk3 though :-D. Definitely less of a science bomb tomorrow :-D.