Tutorial Learning to navigate VASIMR vessels?

[atuhalpa]

After years of using transX and being perfectly satisfied with it's function I have decided to delve into Jarmo's IMFD with both feet and Mark Lieberbaum's IMFD full manual so as to have a tool by which to navigate VASIMR vessels. Do any of you Orbiter veterans have any advice or tips by which to decrease the slope of my learning curve?

 

[Tommy]

From other threads it seems that Hypothetic Delta-V is the way to go for burns that long. P-30 burn mode works better than Velocity Frame, I suspect because the reference vector in Vel Frame changes so much during an extended burn, where the LVLH frame used in P-30 mode changes much less.

 

[Zachstar]

The issue with VASIMR is navigation tools seem to want to take much shorter burn times into account.

VASIMR missions use complex missions that would likely be planned years in advance

 

[Tommy]

I should add that IMFD's map program is your best friend once you figure out how to use it. It's more accurate than anything else, and can show the Hypothetical course created in Hypo Dv. Once you are done accellerating, H Dv can also be used (with Map) for MCC's and tuning the approach decell.

Unfortunately, Target Intercept and the Approach programs won't work well with low thrust vessels.

If you're not familiar with the LVLH reference mode used in P-30 mode, check out Tblaxland's explanation in this thread-

http://orbiter-forum.com/showthread.php?t=10618

 

[Andy44]

We need a good numerical navigation tool for continuous low-thrust travel. We currently don't really have one. AGMFD works for continuous high-thrust flight, at least.

In the meantime, you may be able to do a numerical off-line calculation using VBA or something. Would have to sit down and think about that for a while, first.

 

[computerex]

Well what type of information should the tool display?

 

[Andy44]

Well, just off the top of my head, it should be either an autopilot which adjusts the attitude on the fly as the electric motor is thrusting, or it should provide a cue a la TransX so the Orbinaut can adjust the attitude himself.

The latter would be difficult in time accel, but not impossible, since the attitude, once you've broken free of the planet's SOI, will change rather slowly as you spiral out from or in towards the sun on the way to your destination planet.

The MFD would also have to alert the pilot that the turn-around time is approaching, so you know when to turn around and thrust backwards to slow down as you approach. It would be like using AGMFD in slow motion.

The hard part is the algorithm that drives all that. It has to be a numerical engine of some sort, which takes into account orbit planning and your ship's mass and engine parameters.