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Alkem

1.1.3 RT Probe Control

Question

Hi Guys, 


Having real issues with my (fairly large) Duna probe in an RT install... my signal delay is up to about 2s and I'm trying to do a course correct ion burn... however I'm having major issues aligning with the manouver marker. Neither the ASAS nor the flight computer can actually align to the node - they just circle around it always over-correcting and wasting precious monoprop. I've checked in both RCS buildaid and as the manouvers are conducted and there's no errant 'spin' imparted by unbalanced RCS. Nor is the probe itself unbalanced... it just burns like cray in one direction, overshoots, and burns like crazy back again, like a beagle puppy on a polished timber floor... 

My only thought is that the computers can't cope with the sheer mass (and thus inertia) of the probe - it does weigh in at some 47,000kg... Though I packed SpaceYRCS5x7 thrusters in an effort to compensate... 


Help?

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This may be a stupid suggestion, but I am too curious not to ask anyway.

Have you tried sending a series of commands, "align" - "sas stop rotation" - "align" - "sas stop rotation". If the angle is too far off initially the RCS burn towards 'align' may be too much to stop in time. Sending an "align" followed (shortly after) by a "sas stop rotate" should in my mind get you that little bit closer to alignment. If it works you just repeat the process as needed.

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You may have accidentally set trim and need to clear it by pressing Alt-X.

Do you have reaction wheels, or are you primarily relying on RCS jets?

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I am relying primarily on RCS, though I did include a big 3.75 reaction wheel in a revised launch (after checking CoM) and unfortunatly similar results... 

@Rodhern when I get closer to the marker it does smaller circles, but still never aligns 'propperly' - though it did just fine in the same configuration (ie not dropped anything off) in LKO... so I duoono what's going on :S

 

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