Hello. My name is John. I have an undergraduate degree in Mathematics. I am now classified as a senior citizen. I have always been interested in science. I've been following the progress of NASA's Parker Solar Probe and in the latest blog, Geoff Brown of Johns Hopkins University Applied Physics Lab mentioned before closing, "During the 11-day solar encounter, the spacecraft executed only one autonomous momentum dump – a procedure in which small thrusters are used to adjust the speed of Parker’s reaction wheels." He described more about the event, but it is still not clear to me what is happening. I understand about the conservation of momentum and the gyroscopic effect. I also know that the Parker Solar Probe has to keep its heat shield pointed at the sun through perihelion. I expect to learn more about the construction of the probe in this regard. The Google search that brought me here first pointed to Fi-reefly's question Nov 7, 2012 on this topic with the Hubble Space Telescope at Reference https://www.physicsforums.com/threads/what-is-momentum-dumping.650462/. I expect to read more of this post today. Thank you for your forum and invitation to join the conversation. Peace. PS, I did tweet Neil deGrasse Tyson the question with the hashtag #askNASA, but this is Thanksgiving weekend and I do not expect an answer before December 7th.