Coriolis Station Physics

[Slythe]

Nice work! Although we really should be checking the angles on some of those inverted tower blocks to confirm they are perpendicular to the axis of rotation

David Braben keeps stressing how important the physics and internal consistency are, so I imagine their alignment is pretty good.

I suspect that each individual corridor or apartment has a carefully sloped floor to make sure that "down" is at the right angle. But the walls & ceiling can have a bit of a slope to them without any negative consequences.

 

[Slythe]

...Can someone also work out the diameter of the docking area inside the station? We can then check the simulated gravity on the pads.

Cheers,

Drew.

I just came across a video showing the inside pretty clearly. The internal diameter is roughly 3 times the width of the main hatch, so if all the previous numbers are correct we're talking about 1080m. If the 80 seconds/rotation figure is correct (I havn't tried timing that yet), that results in about 0.34 G simulated on the landing pads.

EDIT:
I just timed the station rotation using Jack Booted Thug's "A Close Look At Zelada Space Port" video, which should work because he was stationary while the station rotated beneath him. This suggests that the time to complete 1 rotation is about 96 seconds, give or take a second or so.

Using that number give a simulated gravity of 0.87G at the extremities of the station (2km from the rotation axis), or 0.63G at the center of one of the square faces (1.44km from the axis). The gravity on one of the landing pads would be about 0.24Gs.

 

[Dirk Braben]

I wish for an x-ray mode.

(isn't there some "force wireframe" in the gfx drivers or such?)

 

[Omegahunter]

I've just worked out, because I could, the internal centripetal G of the Coriolis station and the station isn't rotating fast enough, or it's much bigger than previous estimates.

I assumed that the station was 1km in diameter, as per the original Elite manual.

One complete rotation takes about 80 seconds, about 4.5 degrees s-1

That gives:

Radius (R) = 500 metres
Angular Velocity (Ὠ) = 4.5 degrees s-1

Centripetal acceleration at the outside edge is therefore 0.315 G. Nowhere near enough for the 1G we're after - though it would be quite usable.

To achieve 1G at the outside edge, the Coriolis needs to be significantly larger at the current spin rate.

I've calculated it as follows.

Desired Centripetal Acceleration = 1G
Angular velocity (Ὠ) = 4.5 degrees s-1

Radius (R) = 1590 m

Thus, if the Coriolis is producing 1G at the outside edge, it's over 3km in diameter.

If someone could time the rotation more precisely I can give a more accurate figure.

It would also be interesting to see if people can estimate the size by some cooperative triangulation in the multiplayer, if you can put away your guns for a few moments...

Cheers,

Drew.

Managed to do some checking myself this morning and while it will be a little out I think that it close enough to help.

using the nav beacon as a reference point the rear wall of the station is 3680m away ( basically landed on it )

The front face from the view below is 680m

That makes the space station 3,000 meters front to back.

 

[Slythe]

Alright, finally got off my ****, dug out photoshop from under a pile of shortcuts I havn't used for a while and spent some time making more accurate measurements of the main hatch. After some very careful measurements I am pretty sure that the main hatch is 10% of the width of the entire station.* That includes attempting to compensate for the variations in depth for the different circular sections, especially the section around the hatch itself. Depending on who was closest with their measurements for the overall station, that puts the hatch at between 280 and 300m wide, and 70 to 75m high (as the 1:4 ratio of hatch hight:width still looks good when measuring the pixels).

I'm going to see if I can get some more accurate measurements of the hangar bay now, though I'm not sure if I will be able to compensate for the slope in the bulkhead that contains the hatch.


*The most difficult bit was trying to work out where, among all the girders, the edges of the front square face was.

 

[MrShadowfax]

I have a question which maybe somebody can help me with.

The rotational-assist would need to just roll your ship on its axis when you are in the rotational axis of the cylinder, right? So I guess when you get closer to the circumference of the cylinder, your engines must be firing continually to make your ship trace circles around the station axis, while also spinning on the ship's own axis to keep the bottom of the ship facing the landing pad?

So a pilot using rotational assist would feel zero gravity while on the station axis, but experience gradually increasing "gravity" even as their ship descends away from the station axis, towards the landing pad.

Have I got that right?

Would one of those trucks I can see in the videos have less "gravity" exerted on it if it drove really fast in the opposite direction to the cylinder's rotation?

On some of the videos when people are landing, if their clearance gets timed out I see them kind of slide across the landing pad and then off to the right. Is this also related to the station spin?

 

[Ayo]

I have a question which maybe somebody can help me with.

The rotational-assist would need to just roll your ship on its axis when you are in the rotational axis of the cylinder, right? So I guess when you get closer to the circumference of the cylinder, your engines must be firing continually to make your ship trace circles around the station axis, while also spinning on the ship's own axis to keep the bottom of the ship facing the landing pad?

So a pilot using rotational assist would feel zero gravity while on the station axis, but experience gradually increasing "gravity" even as their ship descends away from the station axis, towards the landing pad.

Have I got that right?

Would one of those trucks I can see in the videos have less "gravity" exerted on it if it drove really fast in the opposite direction to the cylinder's rotation?

On some of the videos when people are landing, if their clearance gets timed out I see them kind of slide across the landing pad and then off to the right. Is this also related to the station spin?

Correct. Though I don't think your engines actually fire (from what I have seen) to compensate for the spin of the station even though they should.

 

[Adept]

Very sadly the game cheats and all coriolis effects... And actually movement seems to be turned off when you are inside the station. In the alpha footage it looks like the station interior is a separate area from the space outside, and it's not actually rotating. I'm sad

I realise btw that landing and taking off manually with realistic coriolis effects would be really hard core... but I was looking forward to trying my hand at it.

 

[noodle]

Very sadly the game cheats and all coriolis effects... And actually movement seems to be turned off when you are inside the station. In the alpha footage it looks like the station interior is a separate area from the space outside, and it's not actually rotating. I'm sad

I realise btw that landing and taking off manually with realistic coriolis effects would be really hard core... but I was looking forward to trying my hand at it.

Are you basing that on something? I was under the impression that the rotation only stopped because the "rotational correction" was set to "on" in the control panel. Didn't they even say that this wouldn't be available in all stations?

 

[Slawkenbergius]

Very sadly the game cheats and all coriolis effects... And actually movement seems to be turned off when you are inside the station. In the alpha footage it looks like the station interior is a separate area from the space outside, and it's not actually rotating. I'm sad

I realise btw that landing and taking off manually with realistic coriolis effects would be really hard core... but I was looking forward to trying my hand at it.

I'm not sure about the depth of coriolis effect simulation, but the space-station is definitely rotating and not separate from the space outside. When you enter the docking area, your ships 'rotational correction' turns on, which applies the thrust necessary to make the pads seem 'still' beneath you. If you turn rotational correction off, then the space-station rotates around you as you'd expect, and makes docking a nightmare.

When you launch from the pad, your ship does veer to the side, but I'm not totally clear what's causing that.

 

[Slythe]

I'm going to see if I can get some more accurate measurements of the hangar bay now, though I'm not sure if I will be able to compensate for the slope in the bulkhead that contains the hatch.

Right, that took a little longer than expected. I was able to narrow down the hangar bay to a diameter of between 670 and 820 fairly quickly, but then began to have to difficulty trying to get a more accurate figure than that. Until I realized that the recessed circle around the main hatch is somewhere between 770-820m diameter and is almost definitely a plug with the same diameter as the internal hangar bay.

So using those figures, with the 96 second rotation measured previously, the simulated gravity on the landing pads is roughly 0.17-0.18 G.

 

[Dejay]

Very sadly the game cheats and all coriolis effects... And actually movement seems to be turned off when you are inside the station. In the alpha footage it looks like the station interior is a separate area from the space outside, and it's not actually rotating. I'm sad

I realise btw that landing and taking off manually with realistic coriolis effects would be really hard core... but I was looking forward to trying my hand at it.

I was a bit sad too. My guess is that if you watch another player you'll see the thrusters fireing constantly to adjust the position though, so it's your ship computer doing it "realistically" and not really cheating.
I had hoped that you will experience "gravity" inside the station, basically once you are outside the center and start to drift with the rotation you only have to create "up" thrust to adjust the rotation. And none in the center. Docking seems way too easy at the moment.

 

[Captain N]

There definitely is both a gravitational effect as well as a coriolis force (which manifests as a sideways pull towards the right) but they aren't really noticeable if you fly with flight assist on. (Why would you do that!)

 

[GreyedOut]

The coriolis effect gets negated while you have docking clearance. Just noticed it in a video where the pilot had trouble docking. When his clearance got revoked, the station immediately "started rotating" around him. (actually, his ship stopped compensating for the rotation)

 

[Adept]

Are you basing that on something? I was under the impression that the rotation only stopped because the "rotational correction" was set to "on" in the control panel. Didn't they even say that this wouldn't be available in all stations?

Yes, a magic toggle. How exactly does that happen? Nothing that is seen in the videos suggests that the station is turning according to normal physics for those on the inside.

 

[Adept]

I'm not sure about the depth of coriolis effect simulation, but the space-station is definitely rotating and not separate from the space outside. When you enter the docking area, your ships 'rotational correction' turns on, which applies the thrust necessary to make the pads seem 'still' beneath you. If you turn rotational correction off, then the space-station rotates around you as you'd expect, and makes docking a nightmare.

When you launch from the pad, your ship does veer to the side, but I'm not totally clear what's causing that.

Hmm, that is promising, but the effect seems very muted. Work out the vector of the ship docked on the rotating landing platform. It points directly sideways along the direction of the rotation. When you lift off you have all that momentum giving you the simulated 0.1 gravity pushing you directly sideways, and into the curving slope of the station's hull.

 

[GreyedOut]

http://youtu.be/UgRcrwt06Qw notice at the 2:35 mark when his clearance gets revoked, his ship stops compensating for the coriolis effect (ship stays in place, station continues rotating). And when he gets clearance again, the relative rotation stops.

 

[metatheurgist]

Docking seems way too easy at the moment.

I can understand that people want to relive the good old days when docking was hard, and I think it's fine for a single player game. But in MP I really don't want to be waiting for people to learn how to dock. Realistically, if docking was such a dangerous and difficult procedure, no one would be allowed to fly unless they were ace pilots.

 

[Susimetsa]

Realistically, if docking was such a dangerous and difficult procedure, no one would be allowed to fly unless they were ace pilots.

Indeed, docking would be fully automated. And I don't really see any reason why it would not be fully automated even if it was easy - just to make it safer for everybody in case a pilot had a seizure or was otherwise mentally unstable (like the ones those "attack everyone everywhere" PvP players are roleplaying )

 

[Mephane]

Yes, a magic toggle. How exactly does that happen? Nothing that is seen in the videos suggests that the station is turning according to normal physics for those on the inside.

http://youtu.be/UgRcrwt06Qw notice at the 2:35 mark when his clearance gets revoked, his ship stops compensating for the coriolis effect (ship stays in place, station continues rotating). And when he gets clearance again, the relative rotation stops.

I suppose if we combine these two thoughts, it would make sense that if you have docking clearance, the ship's computer is linked to the station's traffic controller, automatically adjusting for the rotation, and the only thing actually missing is the corresponding thrusters automatically firing on the ship. Basically a small (yet important for immersion) cosmetic change could alleviate this issue.