Question AR-18 /w IMFD

[Eccentric]

I've been working the learning curve on the IMFD, and feel I have at last the basics correct. However, here is the second time I've had this problem with Orbit Insert, and this is after a clean install immediately prior to testing.

I am running the mission UCGO Missions scenario : Enroute to Jupiter's moons with Orbiter 2010-P1. The following screen shot is taken while well within Jupiter's SOI. I opened the Orbit MFD for additional information. You can see my eccentricity is just barely over 1 so I don't expect a massive burn. Everything looks good on the Map (left normal MFD) and the Planet Approach (right normal MFD). However, though I don't normally open external MFDs for this, I did so now to demonstrate the numbers I see for the Orbit Insertion. I expect to see some value for TtB, but as you can see it is zero, and the BT value is insignificant. Incidentally, the vector it wants to burn at right now is close to prograde.

Despite all this, if I switch the Orbit Insertion from BV back to normal, I see dV 13.84k which is going to take a solid burn for the AR-18. Here is that screen.

Am I doing something wrong? Is there a problem with the AR-18? With IMFD?


P.S. Okay, the gods are messing with me, I think. While I typed this up, I left Orbiter paused. I went back to it just now to check the exact tiny value the Orbit Insertion thought it needed, and I found when I switched to the BV screen, it now says TtB 28.42ks and BT 1.244K. This looks "normal" to me. So any clue what just happened?

This did happen to me once before running Europa to Io, and the burn never happened. I did this run a lot of times (I was following a tutorial) and the problem only occurred once.

I'm wondering if sometimes the MFD just needs some time to catch up or something. Too much demand on my PC's resources? Ideas anyone?

 

[Tommy]

In the first screenshot, you don't have Orbit Insert open - the low dV you see (and the burn vector) are for Planet Approach. Since you are already on course, the low dV is expected. Now look at Planet Approach (main page - not burn vector) and you will see a value called Cir. This is the estimated dV it will take to circularize your orbit at your Pe. In this case, it shows 13.79k. In the second image, you show Orbit Insert - and the dV shown there is 13.84k, pretty close to what Planet Approach was estimating.

It kind of looks like you got confused and thought you were looking at Orbit Insert when you saw the low dV - but were actually looking at Planet Approach instead.

 

[Eccentric]

In the first screenshot, you don't have Orbit Insert open - the low dV you see (and the burn vector) are for Planet Approach. Since you are already on course, the low dV is expected. Now look at Planet Approach (main page - not burn vector) and you will see a value called Cir. This is the estimated dV it will take to circularize your orbit at your Pe. In this case, it shows 13.79k. In the second image, you show Orbit Insert - and the dV shown there is 13.84k, pretty close to what Planet Approach was estimating.

It kind of looks like you got confused and thought you were looking at Orbit Insert when you saw the low dV - but were actually looking at Planet Approach instead.

That was an interesting thought, but I can confirm that it is not so. If the data displayed is not what it should be, the fault is not mine (I think).

At least, it was definitely the Orbit Insert program I had opened in that top-right MFD in the first screen shot. The second screenshot was obtained by only pressing the BV button in the top-right MFD. I cropped the image down to just that MFD before posting it here.

Remember too my closing comment; I left Orbiter paused while I type up the OP, and when I went back to it to read the exact numbers (which I could have taken from the first screenshot I suppose), I again clicked BV and got numbers that looked right.

This did happen once before. I was doing the Europa to Io rescue mission with the AR-18, completed a final Approach burn well within Io's SOI, then selected Orbit Insert and autoburn. When it oriented in a generally prograde direction and began a low power, continuous main engine burn, I soon realized something was wrong. I looked at the BV data and saw similar numbers. Noting about this was in keeping with what I'd have expected from either an Intercept burn nor a Planet approach had I somehow accidentally selected one of those.

In case it helps... Other odd things happen too. I completed the Earth-Europa mission to build a UCGO base (for the umpteenth time) then decided to continue to Neptune (I underestimated how long that would take real-time).

Anyway, along the way, I noticed my correction dV burn oscillated by about 2K. Also, looking at the orbits of Jupiter and Neptune, which I was displaying with IMFD's Map, I saw that their apoapsis and periapsis nodes also oscillated by, oh, maybe 5 degrees.

A thought occured to me, so I used the default Orbit MFD to check on the space stations in the game. All of them, both mine and the ones the scenery/mission file specified, had either crashed to the body they were orbiting, or had been pulled out of its orbit altogether.

I reset the one I had placed around Europa (UCGO version of ISS), and returned to max time acceleration. Immediately I saw its orbit become perturbed, and this rapidly escalated till in maybe a minute it was torn from Europa's orbit. The way it was going it looked like it would eventually land on Jupiter.

Is this a common observation, or is there perhaps something wrong with my installation?