TransX How to adjust trajectory use low delta V?

[NOMAD]

I am doing the voyager 2 mission,when I fly by Jupiter,I try to make a

trajectory correction maneuver.I notice the dv is so high,which is about

500m/s.The total available dv is 281m/s,which means I don't have enough fuel

to adjust trajectory. How to reduce fuel use in a sling-shot flight?

 

[flytandem]

Often you have a choice of how much deltav you make with a correction and what date you arrive at your target (Jupiter). If you really don't care to be exactly on a specific date for the sling then we can work to minimize the deltav of the correction.

I would start by testing a bit of deltav (maybe 20 m/s) in each parameter, prograde, outward and plane change. Add the deltav, note the result in your closest approach to jupiter then take away that deltav to test the next parameter. From this you should see that there is more effect from one parameter over the others. It could be that one is just a bit stronger than another and a 3rd is very ineffective. Use this to determine which one to mostly use for your final solution to the correction.


500 m/s is a fairly large correction burn and might have been reduced with a better eject burn from Earth. Do you have a save from before the eject burn and also from after??

rob

 

[NOMAD]

Before I arrive Jupiter,I have made a trajectory corrention. R. Inc is near to 0,and Pe Ratio is close to 1. After get rid of Jupiter's sphere of influence,I try to make a TCM,however the dv is about 140m/s. I don't know why the dv is high.Can I use about 40m/s dv to make TCM? If it's possible,how can I do?

 

[flytandem]

TransX, though easy for planning slingshots, isn't terribly accurate especially when it comes to slings of Jupiter. I've found that it tends to underestimate the slingshot effect that Jupiter has. To narrow down the flight to less dv used you could do a save when still sun centered stage but just before it switches to Jupiter centered stage. Then test rel inc at zero and Pe Ratio = 1. Do a run through to after it exits the jupiter centered stage and see how it did for the trip to saturn. Then do another test with the Pe Ratio =1.02 or something like that and see how it compared.

What I've wished would be available in TransX is that during the MCC as one is approaching jupiter for example, built into TransX, is a function that allows to utilize just the physics engine of Orbiter, and click an execute or integrate button that takes the current hypothetical maneuver you are setting up and it then does a test integration of what orbiter would end up being if this maneuver were done as planned. It should go fairly fast, maybe a couple of seconds, to integrate several months of flight. One then simply does a series of tests that might take less than a minute and it could save a lot of fuel in future MCCs. ??

 

[Tommy]

TransX, though easy for planning slingshots, isn't terribly accurate especially when it comes to slings of Jupiter.

IMFD has this problem as well. On the Earth-Jupiter-Saturn(Titan) sling I'm working on for the IMFD Full Manual V2.0 tutorial, the first MCC after leaving Jupiter is as large as the plane change used enroute Jupiter, about 10 seconds burn time in a stock DG. The sling, which should leave me on a collision course with Saturn actually leads Saturn by well over 1G. IMFD's Map expected to miss by that much - in the other direction!

What I've wished would be available in TransX is that during the MCC as one is approaching jupiter for example, built into TransX, is a function that allows to utilize just the physics engine of Orbiter, and click an execute or integrate button that takes the current hypothetical maneuver you are setting up and it then does a test integration of what orbiter would end up being if this maneuver were done as planned.

It should be possible to "test" MCC's using IMFD's Delta Velocity program shared with IMFD's Map program (with "Plan" enabled). Map program is quite accurate, it allowed me to begin targeting the Titan Intercept just after leaving Jupiter (skipping a Saturn center "stage")

Once the IMFD Full Manual update is done, I'm thinking of learning TransX with the goal of using it in conjunction with IMFD - a tutorial will follow. Won't be soon - I need to learn TransX "from the ground up" first. I think that using TransX's superior planning capabilities along with IMFD's superior accuracy could lead to some incredibly efficient flights.

 

[NOMAD]

What I've wished would be available in TransX is that during the MCC as one is approaching jupiter for example, built into TransX, is a function that allows to utilize just the physics engine of Orbiter, and click an execute or integrate button that takes the current hypothetical maneuver you are setting up and it then does a test integration of what orbiter would end up being if this maneuver were done as planned. It should go fairly fast, maybe a couple of seconds, to integrate several months of flight. One then simply does a series of tests that might take less than a minute and it could save a lot of fuel in future MCCs. ??

So,can we improve the accuracy of TransX?