Navigation lights in space

[USS Jack Riley]

How about this:

Starsphips, Starbases, etc. use the lights when up close. From a distance, however, why does it have to be just a blinking light? Why can't it also be a radio beacon of soome sort. Each light has its own. The starboard dorsal "light" also sends out a radio or, probably, subspace signal that this spot is the location of the starboard dorsal "light" for those vessels and facilities too far away to see the lights well, or at all.

This way, the lights now serve a dual purpose - a light and a radio/subspace beacon. Now the movement of ships is more easily accounted for as well. You could take it one step further and say that some ships that are shown on the main viewscreen are holograms and that their direction and movement is based on the beacons telling the computer where each of them are, thus giving the ship a 3D (well 4D, but we won't go into that) image of the vessel, its direction and any course changes.

YMMV

 

[BK613]

"True" spacecraft in Trek, such as the workbees and travel pods, don't appear to have red and green navigation lights; they just have beacons for attention.

Timo Saloniemi

FWIW, the ones in TMP do.
From Trekcore, HD theatrical release:
Travel Pod:
Row 1, column 3, here. Port
Row 1, column 3, here. Stbd
Workbees.
Row 1, column 3, here. Port.
Row 2, column 3, same page. Stbd.
And both lights, Row 2, here.

 

[Timo]

Aaargh... High resolution to the anti-rescue!

I was kinda hoping that the people behind that movie would have been more sensible. Or at least more careless, which in the end would amount to sensibility.

Timo Saloniemi

 

[The_Baroness]

Just get a bloke to stick his arm out of the window and point.

Car drivers got by just fine doing that before indicators!

 

[Ian Keldon]

Doesn't this sort of beg the question as to why a starship flying around in deep space would be trying to VISUALLY navigate relative to another nearby vessel? Especially when various types of sensors can give you that kind of information without ever actually needing to SEE the other ship visually (and even when they DO make visual contact, the image is always displayed on the main viewscreen, which makes no attempt to represent bearing or distance).

One word: redundancy. The other ship may be sensor blind or may not have beyond sensor range scanning at all.

 

[Ian Keldon]

You can't blame the banking U-turns of the E-D on "VFX tech shortcomings"! That was a purely artistic choice, and it's difficult to see why the similar movement of the TOS vessel (even if seen in shorter and more ambiguous snippets) would be any more related to VFX shortcomings. If they wanted, TPTB could have shot Kirk's ship going sideways. But Trek starships just plain don't do that.

"Banking" gradual turns make sense under many conditions, as they ease the burden on the Inertial Dampening Field system. The sharper and "tighter" the turn, the more G-force is generated, making the system work harder, and stressing the components.

 

[Crazy Eddie]

Doesn't this sort of beg the question as to why a starship flying around in deep space would be trying to VISUALLY navigate relative to another nearby vessel? Especially when various types of sensors can give you that kind of information without ever actually needing to SEE the other ship visually (and even when they DO make visual contact, the image is always displayed on the main viewscreen, which makes no attempt to represent bearing or distance).

One word: redundancy. The other ship may be sensor blind or may not have beyond sensor range scanning at all.

And yet the other ship does not have the windows or conventional non-electronic optics that would make those running lights in any way useful... even the bridge window in STXI only gives a view of the space directly in front of the ship.

You can't blame the banking U-turns of the E-D on "VFX tech shortcomings"! That was a purely artistic choice, and it's difficult to see why the similar movement of the TOS vessel (even if seen in shorter and more ambiguous snippets) would be any more related to VFX shortcomings. If they wanted, TPTB could have shot Kirk's ship going sideways. But Trek starships just plain don't do that.

"Banking" gradual turns make sense under many conditions, as they ease the burden on the Inertial Dampening Field system.

Banking turns make NO sense in space even if you blame it on the inertial dampeners. A starship wishing to change directions could simply bring its bow around and fire its engines in the appropriate direction to change its vector; this would, in the end, produce even LESS acceleration than a large sweeping/banking turn at constant thrust but changing direction.

 

[Ian Keldon]

Doesn't this sort of beg the question as to why a starship flying around in deep space would be trying to VISUALLY navigate relative to another nearby vessel? Especially when various types of sensors can give you that kind of information without ever actually needing to SEE the other ship visually (and even when they DO make visual contact, the image is always displayed on the main viewscreen, which makes no attempt to represent bearing or distance).

One word: redundancy. The other ship may be sensor blind or may not have beyond sensor range scanning at all.

And yet the other ship does not have the windows or conventional non-electronic optics that would make those running lights in any way useful... even the bridge window in STXI only gives a view of the space directly in front of the ship.

1) you don't know what that ship has or has not, esp in a first contact scenario.

2) that's the one place you DEFINITELY want to be looking in a VFR (visual flight rules) scenario: at what you may be about to hit (or what may be barelling at you.

3) You forgot that both the Kelvin and the JJprise "window" also could display data HUD style, so camera images from other directions could be displayed.

Banking turns make NO sense in space even if you blame it on the inertial dampeners. A starship wishing to change directions could simply bring its bow around and fire its engines in the appropriate direction to change its vector; this would, in the end, produce even LESS acceleration than a large sweeping/banking turn at constant thrust but changing direction.

I'm sorry, but you're wrong again.

"Banking turns" also conserve momentum. A gradual nudge will accomplish the maneuver w/o having to overcome massive amounts of inertia from forward velocity, making the turn more efficient, esp in a reversing course scenario.

 

[Birdog]

I'm sorry, but you're wrong again.

"Banking turns" also conserve momentum. A gradual nudge will accomplish the maneuver w/o having to overcome massive amounts of inertia from forward velocity, making the turn more efficient, esp in a reversing course scenario.

You have no idea what you are talking about. Go download Orbiter and you will see how wrong you are. In space you just point your nose to change vectors. In fact you don't even point it the direction you want to go in most cases.

 

[Ian Keldon]

I'm sorry, but you're wrong again.

"Banking turns" also conserve momentum. A gradual nudge will accomplish the maneuver w/o having to overcome massive amounts of inertia from forward velocity, making the turn more efficient, esp in a reversing course scenario.

You have no idea what you are talking about. Go download Orbiter and you will see how wrong you are. In space you just point your nose to change vectors. In fact you don't even point it the direction you want to go in most cases.

I don't need to download anything, thank you very much. I know that small vector changes require smaller forces than bigger ones, and that therefore the former are better at conserving momentum and more efficient.

I take as my example a 180 degree course reversal. Yes, you could do a 180 x-axis roll and pour on the proverbial gas, but that would be an inefficient use of reaction mass/energy. To get you going the new direction, you would first have to counter all the existing momentum, coming to a stop, THEN start accelerating along your new vector until you regained your former speed.

Or, you could gradually nudge your ship into a banking turn with your reaction thrusters, preserving your momentum and gradually reversing course using far less reaction mass in the process.

It's the same physics that dictates that in the even we needed to divert a rogue asteroid we would do it very far from Earth where we would need a relatively small amount of vector change and therefore a smaller amount of explosive force as opposed to trying to divert it close in where it would take far more force to accomplish the radical vector change needed.

 

[Psion]

I'm sorry, but you're wrong again.

"Banking turns" also conserve momentum. A gradual nudge will accomplish the maneuver w/o having to overcome massive amounts of inertia from forward velocity, making the turn more efficient, esp in a reversing course scenario.

You have no idea what you are talking about. Go download Orbiter and you will see how wrong you are. In space you just point your nose to change vectors. In fact you don't even point it the direction you want to go in most cases.

I don't need to download anything, thank you very much. I know that small vector changes require smaller forces than bigger ones, and that therefore the former are better at conserving momentum and more efficient.

I take as my example a 180 degree course reversal. Yes, you could do a 180 x-axis roll and pour on the proverbial gas, but that would be an inefficient use of reaction mass/energy. To get you going the new direction, you would first have to counter all the existing momentum, coming to a stop, THEN start accelerating along your new vector until you regained your former speed.

Or, you could gradually nudge your ship into a banking turn with your reaction thrusters, preserving your momentum and gradually reversing course using far less reaction mass in the process.

It's the same physics that dictates that in the even we needed to divert a rogue asteroid we would do it very far from Earth where we would need a relatively small amount of vector change and therefore a smaller amount of explosive force as opposed to trying to divert it close in where it would take far more force to accomplish the radical vector change needed.

But when you nudge your nose a few degrees off a course of "0-mark-0", you're still moving along course 0-mark-0. Simply nudging your nose 1 degree or 180 while moving along a vector will do nothing to change the vector along which you're moving. The only way to change your course would be to accelerate while you're nudging your nose. In the end, whether you've accelerated constantly while changing your heading, or simply nudged until you're facing 180-mark-0 and then fired your engines to slow, stop, then move the other direction, you've consumed exactly the same amount of fuel.

There ain't no such thing as a free lunch.

 

[Birdog]

I'm sorry, but you're wrong again.

"Banking turns" also conserve momentum. A gradual nudge will accomplish the maneuver w/o having to overcome massive amounts of inertia from forward velocity, making the turn more efficient, esp in a reversing course scenario.

You have no idea what you are talking about. Go download Orbiter and you will see how wrong you are. In space you just point your nose to change vectors. In fact you don't even point it the direction you want to go in most cases.

I don't need to download anything, thank you very much. I know that small vector changes require smaller forces than bigger ones, and that therefore the former are better at conserving momentum and more efficient.

I take as my example a 180 degree course reversal. Yes, you could do a 180 x-axis roll and pour on the proverbial gas, but that would be an inefficient use of reaction mass/energy. To get you going the new direction, you would first have to counter all the existing momentum, coming to a stop, THEN start accelerating along your new vector until you regained your former speed.

Or, you could gradually nudge your ship into a banking turn with your reaction thrusters, preserving your momentum and gradually reversing course using far less reaction mass in the process.

It's the same physics that dictates that in the even we needed to divert a rogue asteroid we would do it very far from Earth where we would need a relatively small amount of vector change and therefore a smaller amount of explosive force as opposed to trying to divert it close in where it would take far more force to accomplish the radical vector change needed.

No matter how you do it you must cancel your forward velocity. The most efficient manner is thrusting in the opposite direction. Space craft do not fly like planes. This is basic physics. You really should download Orbiter because you don't have a clue about how spacecraft really maneuver.

You are correct that small vector changes require smaller forces but the simple fact is that 180 degrees is 180 degrees no matter what. That is the largest possible vector change.

 

[Ian Keldon]

You have no idea what you are talking about. Go download Orbiter and you will see how wrong you are. In space you just point your nose to change vectors. In fact you don't even point it the direction you want to go in most cases.

I don't need to download anything, thank you very much. I know that small vector changes require smaller forces than bigger ones, and that therefore the former are better at conserving momentum and more efficient.

I take as my example a 180 degree course reversal. Yes, you could do a 180 x-axis roll and pour on the proverbial gas, but that would be an inefficient use of reaction mass/energy. To get you going the new direction, you would first have to counter all the existing momentum, coming to a stop, THEN start accelerating along your new vector until you regained your former speed.

Or, you could gradually nudge your ship into a banking turn with your reaction thrusters, preserving your momentum and gradually reversing course using far less reaction mass in the process.

It's the same physics that dictates that in the even we needed to divert a rogue asteroid we would do it very far from Earth where we would need a relatively small amount of vector change and therefore a smaller amount of explosive force as opposed to trying to divert it close in where it would take far more force to accomplish the radical vector change needed.

But when you nudge your nose a few degrees off a course of "0-mark-0", you're still moving along course 0-mark-0. Simply nudging your nose 1 degree or 180 while moving along a vector will do nothing to change the vector along which you're moving. The only way to change your course would be to accelerate while you're nudging your nose. In the end, whether you've accelerated constantly while changing your heading, or simply nudged until you're facing 180-mark-0 and then fired your engines to slow, stop, then move the other direction, you've consumed exactly the same amount of fuel.

There ain't no such thing as a free lunch.

No there isn't, but there IS a "reduced price" lunch. Conserving your existing momentum allows you to impliment a new vector with much less reaction mass expended.you give your nose a series of nudges with your RCS thrusters while simultaneously applying the aft RCS thrusters and the vector gradually shifts with less mass expended than if you brute forced it with the main engines.

 

[Ian Keldon]

No matter how you do it you must cancel your forward velocity. The most efficient manner is thrusting in the opposite direction.

No you don't and no it isn't. You don't have to cancel it, just redirect it.

Space craft do not fly like planes.

I never said they did. I invoke no drag or lift forces, only pure vector changes.

You are correct that small vector changes require smaller forces but the simple fact is that 180 degrees is 180 degrees no matter what. That is the largest possible vector change.

And you get there most efficiently in terms of reaction mass expended by using RCS to alter your vector and translate the momentum rather than the brute force approach you are talking about.

 

[YARN]

Imagine a sphere flying in space. You want to turn it. Should you bank into the turn or should you just turn?

Banking might make sense as it could be complementary to the AG on the Enterprise, but apart from this there is no sense in banking a turn in space.

And Nav lights in space is pretty goofy. If you are flying by sight in space, you're pretty much hosed. The space shuttle traveled at more than 17,000 MPH. Imagine you're in a ship traveling at a similar speed in the opposite direction. Total speed here is above 34,000 MPH -- assuming you're in a crappy space shuttle, we're talking about closing speed 17 times faster than a rifle bullet. Do you really think eye balling it and reacting via navigation lights is going to help?

Nav lights only make sense at slow speeds in docking-type scenario.

This is yet another reason why Trek is, say it with me, Steampunk-ish.

 

[Psion]

No there isn't, but there IS a "reduced price" lunch. Conserving your existing momentum allows you to impliment a new vector with much less reaction mass expended.you give your nose a series of nudges with your RCS thrusters while simultaneously applying the aft RCS thrusters and the vector gradually shifts with less mass expended than if you brute forced it with the main engines.

Your momentum is along one vector and one vector alone. You can't "conserve" it by magically applying it to a new vector, you have to thrust an amount equal to the difference in the two vectors. No matter how or when you apply thrust, at the end of maneuvering, you'll pay the full price.

 

[Ian Keldon]

No there isn't, but there IS a "reduced price" lunch. Conserving your existing momentum allows you to impliment a new vector with much less reaction mass expended.you give your nose a series of nudges with your RCS thrusters while simultaneously applying the aft RCS thrusters and the vector gradually shifts with less mass expended than if you brute forced it with the main engines.

Your momentum is along one vector and one vector alone. You can't "conserve" it by magically applying it to a new vector, you have to thrust an amount equal to the difference in the two vectors. No matter how or when you apply thrust, at the end of maneuvering, you'll pay the full price.

Not true. In the asteroid diverting scenario I described the mechanism by which the course is changed but not the momentum with relatively small energy inputs. Deflecting is always easier and more efficient than flat stopping, which is why gradual turns is/are/and will always be more efficient than end-flipping and "stepping on the gas".

 

[Timo]

Doing your nudging early vs. late is unrelated to anything much.

Whether gradual turning is more efficient than end-flipping depends on overhead, not on Newtonian mechanics. In the real world, every engine burn is going to have losses - and the likely outcome of that is that many small ones automatically lose to a single big one in efficiency. In pure mechanical terms, only the sum total of force applied along the single vector of interest is of any relevance, as everybody else already realizes - so even a theoretical, lossless engine would benefit from avoiding the extra twists and turns involved in banking, as banking means invoking totally useless sideways vectors (and then having to cancel them out in the end), as well as fighting more rotational inertia than absolutely necessary.

So forget about waving your thrust left and right. The thing you can vary is the force you apply, which directly affects the time you spend effecting your speed change. And even that is of no consequence in any other regard in the ideal situation, although the realistic situation will probably result in more losses when you spend a lot of time doing the losing than when you get it done fast.

There simply isn't anything more to it. Nothing. Not until you invoke drag or lift forces, or their equivalent in the gravitic pull of a nearby body as per the asteroid-deflecting example.

Timo Saloniemi

 

[Lord Manitou]

The most efficient way of changing a vector is to apply force at 90 degrees from where you are moving. If the commander doesn't like that- he can suck mine.

 

[Paul Weaver]

Not true. In the asteroid diverting scenario I described the mechanism by which the course is changed but not the momentum with relatively small energy inputs. Deflecting is always easier and more efficient than flat stopping, which is why gradual turns is/are/and will always be more efficient than end-flipping and "stepping on the gas".

In the asteroid deflection, all we want to do is get the asteroid to change vector enough not to hit us. That means a 20-30 degree change when it's out by the moon, but only a 1 or 2 degree change when it's years away. It's more efficient to do the 1 or 2 degree change.

However, if if you wanted to reverse the asteroids direction, you need to change it 180 degrees. No way around it. The most efficent way (as far as fuel use goes) it to nudge it into a slingshot around a handy planet (the energy to change from 0 degrees to 180 degrees is stolen from the planet's kinetic energy), but if you're in deep space, you need a hell of a lot of delta-v.