Physics of Elite Dangerous

[peteuplink]

As others pointed out, some form of orbit is possible so some basic orbital mechanics must be implemented, but given the delta-v ED ships are capable of it can all be blissfully ignored and just fly in a straight by the seat of you pants as we do. No need to bother with Hohmann transfer orbits. My guess is that thy have implemented some really simple model as any detail would be out shadowed so why bother? Correct multi body orbital mechanics is quite tricky to simulate. Orbiter can also consider the mass distribution of ships which can create some interesting effects when docking .... at v < 1m/s as in rel life.

It would be cool if they allowed to perform some pretend-slingshot maneuvers to make supercruising to distant planets more interesting and a a bit qucikcker

Sorry, but there are no orbital mechanics for ships at all. At least not properly accurate ones as defined by Newtons laws of motion.

Orbiting would only work in space normal speed, not in SC, because the effect of the FSD drive warps space and messes with the mass of the ship, which is why we can fly in straight lines in solar systems using FSD in systems. To put the into context for you, Halley's Comet moves at 254,016 km/h and still moves in an elliptical orbit. For a ship in Elite Dangerous to move at 245,016 km/h it would have to be using FSD and therefore not bound to the same laws of physics as it's currently warping space.

Conversely, The delta-v of the ships in Elite when travelling at space normal speed isn't enough to achieve orbit around Earth. If you exit SC next to a planet you're not in orbit and would never be able to achieve orbit, because you simply cannot go fast enough. The Cobra I fly has a max speed of around 406m/s with boost. The delta-v needed to achieve low Earth orbit starts around 9.4 km/s. So, basically, the space shuttle in low Earth orbit would be travelling faster than a Cobra Mk 3 at its highest space normal speed.

So, basically, and put plainly, the "physics" in Elite Dangerous are bunkum!

 

[John Rhys]

As others pointed out, some form of orbit is possible so some basic orbital mechanics must be implemented, but given the delta-v ED ships are capable of it can all be blissfully ignored and just fly in a straight by the seat of you pants as we do. No need to bother with Hohmann transfer orbits. My guess is that thy have implemented some really simple model as any detail would be out shadowed so why bother? Correct multi body orbital mechanics is quite tricky to simulate. Orbiter can also consider the mass distribution of ships which can create some interesting effects when docking .... at v < 1m/s as in rel life.

It would be cool if they allowed to perform some pretend-slingshot maneuvers to make supercruising to distant planets more interesting and a a bit qucikcker

Orbital Mechanics are implemented. We just don't have anything to measure it, because it's not necessary.

Slingshot in supercruise would not work, since you would be ripped apart with the collapsing warp bubble. That's where the emergency drop comes in, it collapses the warp bubble sort of controlled...doesn't always work perfectly, since you get hull damage (and a lot of structural damage!).

There is no orbital mechanics for ships at all. Orbiting would only work in space normal speed, not in SC, because the effect of the FSD drive warps space and messes with the mass of the ship, which is why we can fly in straight lines in solar systems using FSD in systems. To put the into context for you, Halley's Comet moves at 254,016 km/h and still moves in an elliptical orbit. For a ship in Elite Dangerous to move at 245,016 km/h it would have to be using FSD and therefore not bound to the same laws of physics as it's currently warping space.

Conversely, The delta-v of the ships in Elite when travelling at space normal speed isn't enough to achieve orbit around Earth. If you exit SC next to a planet you're not in orbit and would never be able to achieve orbit, because you simply cannot go fast enough. The Cobra I fly has a max speed of around 406m/s with boost. The delta-v needed to achieve low Earth orbit starts around 9.4 km/s. So, basically, the space shuttle in low Earth orbit would be travelling faster than a Cobra Mk 3 at its highest space normal speed.

So, basically, and put plainly, the "physics" in Elite Dangerous are bunkum!

No it isn't, because the speed itself is no definitive measurement for oribtal mechanics. The Thrust to Weight ration is the thing, that's necessary to "overcome" the gravitational forces, which are dependend on the mass of the "Object". The speed is limited for a reason (to prevent crashes, that would blow a station clean into pieces...crashing a fully laden Cutter with 400 m/s does create damage - crashing it with 255.000 km/h (708333,3 m/s) would blow the station to pieces), but the Thrust is not limited.

 

[peteuplink]

Orbital Mechanics are implemented.

Rubbish, for all the same reasons I just mentioned above.

It's a game, it has very little in terms are realistic orbital mechanics in there aside from the fact that the planets and moons orbit each other. There's no orbital effect on ships.

 

[CMDR Cosmic Spacehead]

Rubbish, for all the same reasons I just mentioned above.

It's a game, it has very little in terms are realistic orbital mechanics in there aside from the fact that the planets and moons orbit each other. There's no orbital effect on ships.

Watch the video.

 

[Mu77ley]

Rubbish, for all the same reasons I just mentioned above.

It's a game, it has very little in terms are realistic orbital mechanics in there aside from the fact that the planets and moons orbit each other. There's no orbital effect on ships.

Try actually watching those videos that were posted.

 

[John Rhys]

Rubbish, for all the same reasons I just mentioned above.

It's a game, it has very little in terms are realistic orbital mechanics in there aside from the fact that the planets and moons orbit each other. There's no orbital effect on ships.

I'll quote myself, since you probably wont read the change:

No it isn't, because the speed itself is no definitive measurement for oribtal mechanics. The Thrust to Weight ration is the thing, that's necessary to "overcome" the gravitational forces, which are dependend on the mass of the "Object". The speed is limited for a reason (to prevent crashes, that would blow a station clean into pieces...crashing a fully laden Cutter with 400 m/s does create damage - crashing it with 255.000 km/h (708333,3 m/s) would blow the station to pieces), but the Thrust is not limited.

 

[peteuplink]

Watch the video.

I've seen the video and it isn't isn't a true orbit, sorry. It's ED's "simulation" kidding you into thinking that it's a real orbit.

This is a real orbit.

[video=youtube;qzMQza8xZCc]https://www.youtube.com/watch?v=qzMQza8xZCc[/video]

YOu see, the "orbit" of Enceladus on the video may work and be good enough to fool people that it's an orbit, but the ships in ED are limited by artificial speed limits that wouldn't apply in real life. So you'd never be able to orbit, say, Mars in the same manner because you'd be unable to go fast enough. The top speed on most ships isn;t able to travel the 9.4km/h needed to achive a steady orbit around an Early-like planet. So, therefore, if you can orbit a planet like Earth or bigger, then there's some fudging going on within the game... basically it's holding you in a circular motion around the planet, not actually relying on a physics simulation to achieve an orbit.

I have lots of friends in the field of astronomy and comsmology, including people who work on The Sky at Night TV show, so I know more about this subject than most.

 

[John Rhys]

I've seen the video and it isn't isn't a true orbit, sorry. It's ED's "simulation" kidding you into thinking that it's a real orbit.

This is a real orbit.

https://www.youtube.com/watch?v=qzMQza8xZCc

So Scott Manley doesn't know oribtal mechanics - is that what you are saying?

An orbit refers to a regularly repeating path around a body, although it may occasionally be used for a non recurring trajectory or a path around a point in space.

So...your definition of "real Orbit" seems different.

 

[peteuplink]

So Scott Manley doesn't know oribtal mechanics - is that what you are saying?



So...your definition of "real Orbit" seems different.

No, my definition of an orbit is the same, I'm saying that the simulation of orbits in ED is not a true simulation of an orbit.

If you want to believe that this silly little game has realistic physics, you do that if it makes you sleep any better. But aside from the galaxy size and the names of stars and some planets, this game lost any semblance of realism a long, long time ago.

 

[xondk]

Supercruise: Alcubierre Drive

Hyperdrive: Tricky, but in game the Hyperdrive "punches" a hole through the Fabric of "normal" Space (or our Universe) and considering the Multiverse Theory , "Witch Space" would be either a "Level II Universe" after Mark Tegmark, or a "Landscape Multiverse" after Brian Green. However, this all involves Quantum Gravity and a lot of other highly theoretical stuff. So unless we get the "Theory of everything" and the missing link to connect quantum mechanics with normal physics...we're not going to get a "real" answer ^^
.

These are one and the same FSD drive handles both, one is basically a 'drive' mode and the other is a high performance mode, using a ton of fuel to cover large distances quickly.

 

[Cupsuki]

In several in game descriptions about Shield data it says they are made of several mathematical layers. I don't know how this really applies to the overall description of a Shield though

 

[Mostly Hamless]

That's entirely down to gameplay reasons.

I wonder what the gameplay reasons for having to slow to 75% at 7 seconds is, because it's certainly nothing to do with either challenge or enjoyment.

 

[John Rhys]

In several in game descriptions about Shield data it says they are made of several mathematical layers. I don't know how this really applies to the overall description of a Shield though

What else would they be made out of? If they are "somekind" of charged fields, there would be quite a lot of math involved. My (rather uneducated) guess is, that the "theory of everything" will not just be one equation and that's that

I wonder what the gameplay reasons for having to slow to 75% at 7 seconds is, because it's certainly nothing to do with either challenge or enjoyment.

You don't have to slow to 75% at 7 Seconds.

 

[beta]

I've seen the video and it isn't isn't a true orbit, sorry. It's ED's "simulation" kidding you into thinking that it's a real orbit.

This is a real orbit.

...

It's not a real orbit unless your escape velocity is at least 16km/s.

So like, screw Mars, Venus, every moon in the Jovian and Saturnian systems ...

 

[Mu77ley]

I wonder what the gameplay reasons for having to slow to 75% at 7 seconds is, because it's certainly nothing to do with either challenge or enjoyment.

That's obvious, it's the same reason you have to slow to go around corners in racing games.

 

[Captain N]

Technically, you can quite easily get into an orbit in ED simply by frame shifting to a station's frame of reference, and since the flight computer automatically sets your velocity to 0m/s relative to the station, voila, you'll be orbiting the planet together with the station! And so far things make sense.

But have you tried to see what happens if you get out of SC and wait in front a station's trajectory in orbit and let the station catch you into its frame of reference? That's right, your ship instantly changes its velocity to match that of the station without either using thrusters or the frame shift drive. Hocus pocus, just like that. No matter how fast the station was moving relative to you.

Also, lore that is based on a hypothetical or speculative idea after another doesn't exactly count as hard science fiction. If something "might be possible" but isn't proven to work, doesn't count as "realistic" in my books.

 

[peteuplink]

It's not a real orbit unless your escape velocity is at least 16km/s.

So like, screw Mars, Venus, every moon in the Jovian and Saturnian systems ...

Of course it's a real orbit! it's live, happening now, in orbit around our planet. The delta-v needed to achieve low Earth orbit starts around 9.4 km/s. Atmospheric and gravity drag associated with launch typically adds 1.3–1.8 km/s to the launch vehicle delta-v required to reach normal LEO orbital velocity of around 7.8 km/s (28,080 km/h).

Anyway let's have a look at this video of an "orbit" in Elite Dangerous.

[video=youtube;XE7WPstMzsM]https://www.youtube.com/watch?v=XE7WPstMzsM[/video]

If we look at the video at 0:20 you'll see that he zeros his pitch angle and cuts his thrusters at a height of 8.9km above the moon at a speed of 172m/s, And then we enter a time lapse of the orbit. All well and good.

However, at the 3:03 mark of the video, you can clearly see that that the main thrusters of the ship start firing with a nose down attitude. Firing you engines like this while in orbit would alter your speed and therefore the trajectory of your orbit. The engines fire for 33 seconds until the video fades. While the engines are firing the video reaches the 3:24 point where he says "Three hours later. Ship returns to original position at the same speed." but if this was a true orbit, the fact that the engines are firing and that he was nose down would mean that he would not be at the same speed and would likely have dropped to a much lower orbit, if not out of orbit entirely by that point. Enceladus is only small and a 33 second burn would have big consequences on an orbit.

What I say is happening here is not that the maker of the video is actually orbiting the moon using orbital physics, but rather that he is simply flying around the planet using the same game systems that would keep you from crashing if you were flying at 172m/s at 1km above the surface.

The true test to see if it's real orbital mechanics would be to change your velocity and seeing if that raises or lowers your orbit in accordance to Newtons laws of physics. If your orbit trajectory doesn;t change and you simply speed up, you're not in an orbit. You're just flying around by artificial means that are programmed into the game.

Sorry, but that's the truth.

 

[beta]

Heavy sarcasm.

A lot of planetary bodies in E: D can be orbited "properly", you simply have to pick bodies where your "maximum velocity" is not a concern.

Sure, its not N-body physics, but there is representation.

 

[shadragon]

Why not do it suddenly and turn the occupants of the target ship into jam rather than having to fight them after they've slowed down?

Inertial dampers. Sci-fi 101.

It's almost as if this stuff was just invented so it'd be convenient for a video game.

Your point being?

 

[Monk]

here is an old, but very good thread, especially the parts about supercruise and hyperjumps: https://forums.frontier.co.uk/showthread.php/106861-DCello-s-Science-Guide-to-the-Galaxy

Oh, that was such a good thread. I'd pretty much forgotten everything I wrote in there. Dcello was a good fella (if not a little abrasive, at times)...been gone a long time now