Powered descent guidance are a class of rocket landing algorithms developed at NASA's Jet Propulsion Laboratory to bring the 2012 Curiosity rover to the Martian surface. These algorithms compute the thrust to land systems on a planet in a fuel optimal manner by rapidly burning propellant, that results in a rapid change in the overall mass of the system in a short period of time. One of the algorithm's developers subsequently drove the SpaceX's reusable rocket program to pioneer the rockets on Earth; these systems are much bigger than the Martian missions and are thus even more reliant on variable mass system dynamics. In future, large Martian landers (such as SpaceX's Starship) will need development of the next generation of landers. the control volume approach, based on Reynold’s transport theorem in fluid mechanics, is most comprehensive in that it accountsfor details of mass-flow effects, but some of the integrals arising in this approach are very difficult to evaluate” Yellow Highlight [Page 1](zotero://open-pdf/library/items/Q44PZISV?page=1&annotation=YLBP7HNA) Simulation of a system of flexible bodies with variable mass, described by many time-varying modes, requires computational efficiency considerations” Yellow Highlight [Page 1](zotero://open-pdf/library/items/Q44PZISV?page=1&annotation=9YCTDUD5) it is desirable to use order-n formulations and parallelprocessing algorithms.” Yellow Highlight [Page 1](zotero://open-pdf/library/items/Q44PZISV?page=1&annotation=TU4MZ7HX) A flexible-bodyrocket with a gimballed nozzle may be treated as two articulated bodies, with the flexible body subjected to combustion and associated mass loss and the nozzle modeled as rigid with invariant mass.” Yellow Highlight [Page 3](zotero://open-pdf/library/items/Q44PZISV?page=3&annotation=TCE9TEVI) **Next notes** - [[2a General Variable Mass Systems (GVMS)]] - [[2b Alternative Non-propulsive Landers]]