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Seeking a Sublight Travel Calculator

Hi !

I will provide some meta-code here in this
thread.
Guess its best for understanding and might
be useful to be incorporated into any program
dialect or spreadsheat


Regards,

Mert
 
Hi,

here comes some math and code...

Most of this stuff is an extract of one of
my more "professional" physic books


The basic formulars for calculating travel
times of an accelarated body of constant
mass become much more mathematically handy, if
we perform some simple substitutions resulting
in some variables without any dimension.

V=v/c v=velocity(m/s)
T=(a*t)/c t=time(s)
X=(a*x)/c^2 x=distance(m) and a=accel(m/s^2)

The basic relation between time and velocity
is given by
v = c * sqr( (g*t/c)^2 / (1 + (g*t/c)^2))

After applying the substitutions you get

V = sqr( T^2 / (1+T^2) )

In order to get the distance you have to
integrate V(T) resulting in

X = sqr(1+T^2) - 1
resolved by T
T = sqr( (X+1)^2 - 1 )

These are values in the destinations reference
frame.
The time passing in the accelarated frame is
calculated with:

T' = arcsin T

In order to get values in usable units you have
to revert substitutions....

O.k., this put in some code:

Substitution ddist > dLJDist (x > X)
dLJDist = (dDist * 9.81 * tbG) / (c ^ 2)

Calculation of dTime (T)
dTime = Sqr((dLJDist + 1) ^ 2 - 1)

Revert substitution to get dTimeS (t) in seconds
dTimeS = ((dTime * c) / (9.81 * tbG))
Thats the time needed to move a distance of ddist
in accelerated way.

Calculate speed (V)
dRelV = c * Sqr(dTime ^ 2 / (1 + dTime ^ 2))

Calculate time in accelerated frame (T')
dRelTime = Log(dTime + Sqr(dTime * dTime + 1))
Thats the same as dRelTime arcsinh dTime but
most languages do not provide this function
directly.

Revert substitution to get time in seconds
dRelTimeS = ((dRelTime * c) / (9.81 * tbG))
This the time passing in the accelerated frame.

So, thats all You need.
If you want to calc mid-turn trips, just divide
original distance by two, do calcs and finally
double the "time" results. Just as usual...

A little bit more complicate is to calc travel
times with a speed limit set.
Here you would have to subdivide travel into
accelarated sections and constant speed sections.

In order to get the time dilation effect for
constant speed travel you could use

dRelTimeS = dTimeS * Sqr(1 - (V ^ 2) / (c ^ 2))


I hope, this stuff is ok that way

If anybody should find some flaws I am quite sure
these will be presented in this board


Trusting these calcs, relativistic effects seem
to be neglegtable for most of the standard Traveller
travel procedures anyway.....

Regards,

Mert
 
Engineer,

Could you PLEEEEEASE post a download link of your program? I would be most grateful for a tool for calculating space travel equations.

Thanks!
 
I have a basic distance-time-acceleration calculator in JavaScript here:

http://home.comcast.net/~downport/perl/travel.html

Given any two of the three, the third will be calculated. Time units of seconds, minutes, hours, and days are understood, and distance units of km and AU are understood.

Times calculated are round-trip times.

Near-C effects are not taken into consideration :(
 
Originally posted by TheEngineer:
Hi !

I will provide some meta-code here in this
thread.
Guess its best for understanding and might
be useful to be incorporated into any program
dialect or spreadsheat


Regards,

Mert
Mert--

Thank you! Thank you! Thank you! Thank you!

I've been trying to put together a spreadsheet to show travel times (destination and travel frame of reference) given a certian acceleration between the nearest stars for *years*.

Now I have it. Work on this project can actually get started.

Thanks so much!

--michael
 
Hi !

Sorry for a loooong delay, but I had to take care for a very special project

Now my daughter Maren is born ( Maren) and even if there is less time than before I managed to put some pieces of software on this page.

Here ( Calculator Program) you can download a fairly simple VB6 project/source (also executables) which does all the calculations....

Regards,

Mert
 
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