In the SOHO mission Event List SOHO Event List there are a few terms I am hoping to understand.

I assume MCC1 X-1 Burn refers to a mid-course correction. What does the number 1 and X-1 mean?

For the event Momentum Management; +3500/+600/+1000, can that be described in terms a second year undergraduate physics major would understand? Does this event refer to the Halo orbital insertion?

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    $\begingroup$ Just a guess, but the MCC1 X-1 and X-2 might be two different opportunities for the first midcourse correction -- only one or the other would be used (so they aren't MCC1 and MCC2). No idea on Momentum Management. $\endgroup$ – Russell Borogove Nov 21 '18 at 17:57
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    $\begingroup$ @RussellBorogove For Momentum Management there's a triplet of signed numbers, suggesting the amount of angular momentum about three axes? $\endgroup$ – uhoh Nov 21 '18 at 21:02
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    $\begingroup$ @uhoh Thank you. That explains the Momentum Management enough for me to be able to use it in my novel. $\endgroup$ – Bob516 Nov 21 '18 at 21:45
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    $\begingroup$ @Bob516 momentum management is about the attitude (orientation) of the spacecraft, not the trajectory. In space it's hard to keep satellites pointing in one direction without rotating. If this is what I think it might be, then it's using thrusters to try to spin the spacecraft in one direction while simultaneously slowing down the spin rate reaction wheels. This has almost zero effect on the trajectory or orbital insertion. Imagine sitting on a chair on wheels spinning while rolling down a hall. You can use a gyroscope to change your spin rate, but your rolling down the hall won't change. $\endgroup$ – uhoh Nov 21 '18 at 21:52
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    $\begingroup$ @Bob516 That doc says that the first MCC is 1.5 days after injection and the second is 20 days after injection. The event list shows MCC1 X-1 and MCC1 X-2 are 18 hours apart, and X-1 is about 1.5 days after separation from Centaur (which must be shortly after injection). So either X-1 and X-2 are two opportunities for MCC1, or X-1 is the main correction, and X-2 is a "correction to the correction". I don't know why the second correction (~day 21) isn't in the "SOHO Events List". $\endgroup$ – Russell Borogove Nov 21 '18 at 22:01

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