Sub-light travel times

[ReaverKing]

Second question guys,

I'm looking at generational ships and not sure how to calculate travel times.

Given current and possible proposed technology, how long on average would it take to get between worlds 1 parsec apart at sub-light speeds?

Thanks,

Brett.

 

[pendragonman]

Second question guys,

I'm looking at generational ships and not sure how to calculate travel times.

Given current and possible proposed technology, how long on average would it take to get between worlds 1 parsec apart at sub-light speeds?

Thanks,

Brett.

Really depends on how big a fraction of light speed you achieve.


A parsec is ~3.3 LY. Suppose you get to .3C or 3 tenths of the speed of light. Then the trip would be ~11 years for the people on the generation ship.

But then you are playing Relativity games. Schaum's outline for Relativity is helpful.

 

[ReaverKing]

Really depends on how big a fraction of light speed you achieve.


A parsec is ~3.3 LY. Suppose you get to .3C or 3 tenths of the speed of light. Then the trip would be ~11 years for the people on the generation ship.

But then you are playing Relativity games. Schaum's outline for Relativity is helpful.

Wow, I really thought it would take a lot longer than that. Is .3C achievable with current tech?

 

[pendragonman]

Wow, I really thought it would take a lot longer than that. Is .3C achievable with current tech?

Not currently. But you said currently or proposed. See below

https://en.wikipedia.org/wiki/Alcubierre_drive

http://www.techtimes.com/articles/5...loser-reality-warp-theoretically-possible.htm

http://blogs.scientificamerican.com/life-unbounded/the-fastest-spacecraft-ever/

 

[ReaverKing]

Not currently. But you said currently or proposed. See below

https://en.wikipedia.org/wiki/Alcubierre_drive

http://www.techtimes.com/articles/5...loser-reality-warp-theoretically-possible.htm

http://blogs.scientificamerican.com/life-unbounded/the-fastest-spacecraft-ever/

True, I did say that. Thanks for the links, the EM drive is very interesting.

 

[ReaverKing]

Really depends on how big a fraction of light speed you achieve.


A parsec is ~3.3 LY. Suppose you get to .3C or 3 tenths of the speed of light. Then the trip would be ~11 years for the people on the generation ship.

But then you are playing Relativity games. Schaum's outline for Relativity is helpful.

Googled Schaum's outline for Relativity, ooh, that's way over my head.

 

[Nathan Brazil]

T5.09 rules have NAFAL (Not As Fast As Light) drives with ratings 1-9 (meaning .1c per) along with the percent of onboard vs outside time.

 

[aramis]

Second question guys,

I'm looking at generational ships and not sure how to calculate travel times.

Given current and possible proposed technology, how long on average would it take to get between worlds 1 parsec apart at sub-light speeds?

Thanks,

Brett.

Given the speed of light as constant C... and using (for simplicity) 3e8m/s
Acceleration A = is in m/s²
and G's are convenienced to 10m/s²...

Generally, figure out how fast you care to allow them to go (as a fraction of C)... Call it v[/v]

Let the distance in LY = d

Real Time taken in years T_y is roughly T_y=d/v.

Perceived time... P... is roughly P=T*(1-(v²/C²))

Acceleration time is roughly T_a=3e8/(A*9.4608e15)... but that's before speed causing dilation... and is also in years...

I never took calc... so I can't solve the integral for the acceleration...

 

[Enoff]

Relativistic Star Ship Calculator
http://convertalot.com/relativistic_star_ship_calculator.html

 

[aramis]

Relativistic Star Ship Calculator
http://convertalot.com/relativistic_star_ship_calculator.html

Won't let you cap maximum β (maximum speed)... which is a consideration. Also note, the safe speed in the OTU, per Game 0: Imperium, the 1/2 parsec hexes and maximum speed per 2 year term is 1 hex during the Nth Interstellar Wars era (so 4 years for 3.26 Pc) - peak speed in external frame is 0.81 C,

definitions:
₀ means external reference time
₁ means on-board (perceived) time
_a for acceleration to maximum safe speed
_c While coasting (maintaining low thrust for interstellar medium drag)
_t Total (_a+c)
T time.
τ Time dilation factor Tau.
D=Distance in LY.


τ_c=0.5864298764558299




Using the calculator recursively 1.38 LY Accell/Decell distance, and a external frame time
T_0a=2.6739142547696746 years (about 488.3 days each up and down)
and subjective time
T_1a=2.170406894251718 years (About 396.5 days each up and down)


Coasting
T_0c=1.2269938650306749 per LY (about 224 days)
T_1c=0.7195458606819999 per LY (about 131.4 days)

So, keeping to 3 place accuracy...
For distances greater than 1.38 LY... and 1G accel...

T₀=2.67+((D-1.38)*1.23)
T₁=2.17+((D-1.38)*0.72)

Under that, the calculator works.
I used Traveller standard (as denoted in TNE explicitly, and buried in the math for MT) of 10m/s²

In Earth standard 1G, instead...
T_0a=2.7300579259550095 y (497.2 ea up and down)
T_1a=2.2151820320106164 y (404.5 ea up and down)
D<sub>a[/sub=1.41 LY

So, keeping to 3 place accuracy...
For distances greater than 1.41 LY...

T0t=2.73+((D-1.41)*1.23)
T1t=2.22+((D-1.41)*0.72)

Gives some pretty nifty numbers...

At 6Gearth, the distance is 0.235 LY,
T0a=0.4550096543258349
T1a=0.3691970053351028
T0t=0.455+((D-0.235)*1.23)
T1t=0.369+((D-0.235)*0.72)

A 6GTraveller, distance is 0.23 LY,
T0a=0.44565237579494577
T1a=0.36173448237528627
T0t=0.446+((D-0.23)*1.23)
T1t=0.362+((D-0.23)*0.72)

I'm too lazy to fill in the other points... tonight, at least.</sub>