Question on Dres Encounter

[toomuchbrew]

Ok, so I decided to send out a probe to Dres having already completed the Duna/Ike Impactor mission. I wanted to orbit Dres while doing the science experiments high/low Orbit and then science until I crash. When I got to Dres, I was going about 3.4km/s. I had to do an inclination burn to meet up closer to Dres as my initial burn put me below Dres. I was able to get my PA down to about 32k after a few reloads. I am just going too damn fast to get into even a highly eccentric orbit. My craft has about 1.7k Dv after correction burns. It isn't enough to slow me down so I either crashed or skipped out of Dres's SoI. Is there a way to cut down on my Dv requirement or am I just stuck with a crater? Obviously can't aerobrake. Regardless of the answer, that mission is done as I get enough science. I will send a new mission there at some point. My craft weighs about 10T and I am using a single nuclear engine. Did I screw up my transfer, coming in too hot or is that high speed normal for a Dres transfer/encounter. Thoughts?

Edited October 23, 2013 by toomuchbrew

[wasmic]

MOAR ÃŽâ€V.

Oh, and not all Dres ttansfer windows are equally good. Some of them require a huge inclination change, while some (very few) requires none. Be sure to launch at a transfer window that requires as little inclination ÃŽâ€V as possible.

[toomuchbrew]

Used mechjeb for my transfer, so that got me pretty close. My other question: when I complete my transfer burn, I may not have an encounter. How I have been doing things is to set up an inclination burn either up or down at the first acsending or descending node. Is that correct/proper? Using nodes, sometimes there is too much info in the same spot so it is hard to read. Does it matter which side of the object I am going to fly-by?

Edited October 23, 2013 by toomuchbrew

[JebidiahsBigSister]

I'd never considered that before but I can visualize what you are talking about - good point !

[toomuchbrew]

I'd never considered that before but I can visualize what you are talking about - good point !

To which point are you referring?

[Kerbonautical]

Used mechjeb for my transfer, so that got me pretty close. My other question: when I complete my transfer burn, I may not have an encounter. How I have been doing things is to set up an inclination burn either up or down at the first acsending or descending node. Is that correct/proper? Using nodes, sometimes there is too much info in the same spot so it is hard to read. Does it matter which side of the object I am going to fly-by?

As a mechjeb user theres an easier way to do this. Click along to the fine tune closest approach tool under manouvre planner.

[toomuchbrew]

As a mechjeb user theres an easier way to do this. Click along to the fine tune closest approach tool under manouvre planner.

I never noticed it. I will have to check it out. I only started going to other planets since .22 in career mode. Out of curiosity, does fine-tuning mean that it will give you a good orbit while maximizing fuel efficiency or does it just perform an adjustment to get the encounter from after the transfer burn?

Does it perform aerobraking maneuvers when fine-tuning to objects with atmo?

Thanks for pointing this out. I am intrigued.

[toomuchbrew]

Am I using the ascending/descending nodes correctly? If it shows other than zero, that is where I do my purple burn on the node, correct?

[Kerbonautical]

I never noticed it. I will have to check it out. I only started going to other planets since .22 in career mode. Out of curiosity, does fine-tuning mean that it will give you a good orbit while maximizing fuel efficiency or does it just perform an adjustment to get the encounter from after the transfer burn?

Does it perform aerobraking maneuvers when fine-tuning to objects with atmo?

Thanks for pointing this out. I am intrigued.

It will work out an efficient point to correct your approach during orbit of the sun, usually about halfway through. MechJeb doesn't appear to understand aerobraking however. Either that or it does and I'm not entirely sure what the term implies which is the most likely answer. It's not bad at it though, I had a Dres encounter last night and I burnt around 200 Delta V correcting and the standard amount on arrival. The correction did put me on course for a 90 degree inclination which needed to be corrected after reaching the SOI though.

By the way I also had a failed attempt using MJ prior to that which left me with Delta V calculations that were about 5k over the expected quantity so you may have hit the same issue I did. I have no idea what caused it still.

[Oddible]

There are several things you can do to smooth things out. Yes, doing an inclination change at the AN/DN can help to keep you in Dres's SoI longer so you have a better chance to stick. I do wish that the UI currently showed your resulting speed when you have a maneuver node active. Would be nice to see the relative speed to your target.

[toomuchbrew]

Cool. Thanks. It sounds like I am not the only one. I will do another Dres probe mission tonight. I just could not stay up any later. Stupid work, ruining my rocketry career

[toomuchbrew]

There are several things you can do to smooth things out. Yes, doing an inclination change at the AN/DN can help to keep you in Dres's SoI longer so you have a better chance to stick. I do wish that the UI currently showed your resulting speed when you have a maneuver node active. Would be nice to see the relative speed to your target.

My biggest peeve is on the map mode, when trying to do encounter nodes on small celestial bodies, it gets nearly impossible to tell what's what.

Edited October 23, 2013 by toomuchbrew