The Sun-Earth space weather related to sunspots NOAA 484, 486, and 488 affected a number of NASA spacecraft and instruments between mid-October and early November 2003. Information available from Earth and space science missions indicate that about 59% of the spacecraft and about 18% of the instrument groups experienced some effect from the solar activity. This paper summarizes the impacts on spacecraft, instruments, and science data. The database that the paper is based on describes spacecraft and instrument effects observed as well as mission operators' preventive actions from 34 reporting missions. The database is Appendix A and provides additional material that could be of interest and that could be useful to satellite developers, operators, instrument managers, and scientists. The types of environmental effects observed were electronic upsets, housekeeping and science noise, proton degradation to solar arrays, upper atmosphere–induced changes to orbit dynamics, high levels of accumulated radiation, and proton heating. The paper develops best practices that are intended to foster continued and expanded feedback on the space environment in all mission phases, to promote designing to the mission's observing mode so that planning is appropriate to mission science goals, to distribute operational experience and lessons learned widely among both developing and operating missions, and to uniformly apply the developed knowledge base among NASA's missions.