Earth to Mars Trajectory

I have a full windows simulation of the Earth to Mars trajectory on my
website, with free downloads. No experience in orbital mechanics is
necessary.

Bar X Software
http://www.bar-x-soft.com

It's written in Fortran and the Windows GUI was done with
Winteracter. The routine is accurate to 16 significant digits, and
was done with a Runge Kutta 7/8 integrator. The unzipped routine is
less than 3 megs and it takes only a few seconds to complete the
analysis ~ finding the optimum trajectory with the inputs given. The
best I have done so far uses 25% less energy than a Hohmann (there are
a dozen variables you input, if you want). Many user options that can
be selected and input, then the optimized trajectory is calculated and
printed out on the screen, all the raw numbers for each step of the
integrator are available as well. There are help files and plots
showing how the optimization routine itself works. All of this was my
Ph.D research at Texas, under the late Roger Broucke, a famous
researcher in Celestial Mechanics (and a real computer nut - you
guessed it, a Fortran fan!)

It's a fun program and very educational ~ makes you see just how hard
it is to reach Mars!

Bill wrote:

I have a full windows simulation of the Earth to
Mars trajectory on my website, with free
downloads.

The link you gave leads only to advertising for
some other, for fee, software package entirely.

No experience in orbital mechanics is necessary.

It's written in Fortran and the Windows GUI was
done with Winteracter.

Never heard of it, but then I use and still despise
MS-Windows.

The routine is accurate to 16 significant digits,
and was done with a Runge Kutta 7/8 integrator.

Ah the days of high precision math for personal
computers sure are fine days indeed for hobbiests.

The unzipped routine is less than 3 megs and it
takes only a few seconds to complete the analysis
~ finding the optimum trajectory with the inputs
given.

While a hill-climbing (or whatever) deterministic
algorithm may be the first obvious choice to you,
the degrees of freedom you allow suggests that
exploring use of a genetic algorithm might prove a
fruitful alternative, though probably not as fast a
one.

The best I have done so far uses 25% less energy
than a Hohmann (there are a dozen variables you
input, if you want).

I know zero about orbit calculations, but for a
manned flight, wouldn't "minimum time given an
affordable energy supply" be a more worthwhile goal
than "minimum energy to arrive at all"?

Or am I missing something obvious that equates the
two?

Many user options that can be selected and input,
then the optimized trajectory is calculated and
printed out on the screen, all the raw numbers for
each step of the integrator are available as well.

The eyes glaze over.

There are help files and plots showing how the
optimization routine itself works.

Please provide a working link, and maybe we can take
a look at your work.

All of this was my Ph.D research at Texas, under
the late Roger Broucke, a famous researcher in
Celestial Mechanics (and a real computer nut - you
guessed it, a Fortran fan!)

While I have an undue fondness for Fortran [some
Fortran fans credit a rant I posted to Usenet that
got reprinted by someone else in Fortran Letters for
changing the direction of the Fortran 8x standard
that eventually became Fortran 90, from "tweek" to
"total rewrite" -- I have no way to know if that is
true, though], unless you are tied to BLAS or
something similar in the way of a numerical software
library, why not a more modern programming language
that would make your software accessible to a larger
audience?

Fortran is dragging a _lot_ of baggage these days.

It's a fun program and very educational ~ makes
you see just how hard it is to reach Mars!

Getting past the solar flare problem is going to
require some world class shielding, and the cheapest
way to put it in orbit is probably from the moon
rather than from Earth, but then that requires a
quasi-permanent lunar settlement.

If you want a (much) bigger project next time, do
the energy balance for doing the vehicle
launch, construction and fueling using matter from
two bodies, earth and moon, using "reasonable
assumptions" about getting and sustaining a work
force on the moon, and which said assumptions are
parameters of the run.

xanthian.