[Need some help] Simulation on mission to Alpha Centauri

[corous]

Calling on my fellow Kerbalnauts with the Real Solar System mod (and possibly other realism mods for existing rockets / launchers etc.) for help. This should only take an hour or so of your time.

I'm working on a rough simulation on a mission to Alpha Centauri and would like some help. Back of a napkin calculation says it should be possible with existing rockets, I'm also setting the mission up using NASA's General Mission Analysis Tool (GMAT), but a second set of eyeballs is always welcome. So, I thought, what better tool than KSP?!

The mission is to send a 50kg payload into a direct ascent solar escape trajectory towards Alpha Centauri at 50 km/s, i.e. no gravity-assist trajectory around Jupiter etc. and using chemical rockets only. And don't forget that Alpha Centauri lies outside of the Earth's orbital plane. From GMAT, it looks like it's generally in the southwest with respect to the Earth's axis of rotation.

The reason I initially considered a direct ascent escape trajectory is because the target star system is out of the solar system's planetary plane, but you're certainly welcomed to try a gravity assist trajectories via the Moon, Venus or Mercury. The velocity gain from "falling towards" the Sun might indeed be quite significant.

So, again, here's the mission parameters:

1. Spacecraft dry mass: 50 kg

2. Min. Velocity (after final burn of upper / kick stage): 50 km/s

3. Existing launch vehicles preferred: Soyuz, Proton M, Delta IV, Atlas V, SpaceX Falcon etc.

Please post your results of velocity achieved with the type / fuel mass of launch vehicle used.

Thanks in advance,

corous