Newcomer / Intro Distance and time to travel to objective.

[Touchwood]

I'm fascinated by the mechanics that drive the "time to travel to objective" readout when supercruising - the lower figure in the readout.

Unless I'm mistaken, the program is trying to predict the time it will take to reach the objective, with constantly varying speed and acceleration. So, it starts at maybe > 1 year, as speed increases the time ticks down at an ever increasing rate, until on approach when speed begins to drop the rate slows again.

Problem is, it seems to exhibit some pretty unusual behaviour. I've not actually recorded readings and done sums, but the rates of increase and decrease don't seem always to tally with the changing velocity. I've even seen the time start to increase as the distance decreases!

Surely, all the sums to calculate the speed changes are in the software, so why can't this figure do the one thing it just doesn't ever do at the moment, which is to tell you how long it will be before you arrive?

 

[Robert Maynard]

The estimated time to destination is the distance to run divided by the current speed - as one approaches the destination, gravitational effects generally start to slow the ship down (even if the throttle position is unchanged) - hence the TTD may increase as the speed decreases due to the proximity of the destination.

 

[Winterwalker]

I'm fascinated by the mechanics that drive the "time to travel to objective" readout when supercruising - the lower figure in the readout.

Unless I'm mistaken, the program is trying to predict the time it will take to reach the objective, with constantly varying speed and acceleration. So, it starts at maybe > 1 year, as speed increases the time ticks down at an ever increasing rate, until on approach when speed begins to drop the rate slows again.

Problem is, it seems to exhibit some pretty unusual behaviour. I've not actually recorded readings and done sums, but the rates of increase and decrease don't seem always to tally with the changing velocity. I've even seen the time start to increase as the distance decreases!

Surely, all the sums to calculate the speed changes are in the software, so why can't this figure do the one thing it just doesn't ever do at the moment, which is to tell you how long it will be before you arrive?

This is going to sound weird but it could be making a "relativistic" calculation ..

I don't have a complete analysis of it (will leave that to the boffins!) but in real-world time and space, you can't travel faster than the speed of light, in supercruise you can. The frameshift bends the gravitational field around the ship and this is a distortion of space-time. Distance (space) and Seconds (time, being space-time) can't be linear anymore so I think the only thing you can really rely on is the Universal Constant, the speed of light.

So as the distance/time to destination readouts are at best a guide and as your best guide is "light" ..
If I see the planet I'm heading to getting bigger, I slow down ..