Editing Advanced Composition Explorer (section)

=== Solar Wind Electron, Proton and Alpha Monitor (SWEPAM) ===
[[File:ACE-swepam sm.jpg|thumb|SWEPAM]]
The Solar Wind Electron Proton Alpha Monitor (SWEPAM) experiment provides the bulk solar wind observations for the Advanced Composition Explorer (ACE). These observations provide the context for elemental and isotopic composition measurements made on ACE as well as allowing the direct examination of numerous solar wind phenomena such as [[coronal mass ejection]], interplanetary shocks, and solar wind fine structure, with advanced, 3-D plasma instrumentation. They also provide an ideal data set for both heliospheric and [[magnetospheric]] multi-spacecraft studies where they can be used in conjunction with other, simultaneous observations from spacecraft such as [[Ulysses (spacecraft)|Ulysses]]. The SWEPAM observations are made simultaneously with independent electron (SWEPAM-e) and ion (SWEPAM-i) instruments. In order to save costs for the ACE project, SWEPAM-e and SWEPAM-i are the recycled flight spares from the joint [[NASA]]/[[European Space Agency|ESA]] Ulysses mission. Both instruments had selective refurbishment, modification, and modernization required to meet the ACE mission and spacecraft requirements. Both incorporate electrostatic analyzers whose fan-shaped fields of view sweep out all pertinent look directions as the spacecraft spins.<ref name=mccomas98>{{cite journal |last=McComas |first=D. J. |title=Solar Wind Electron Proton Alpha Monitor (SWEPAM) for the Advanced Composition Explorer |journal=Space Science Reviews |date=July 1998 |volume=86 |pages=563–612 |doi=10.1023/A:1005040232597 |bibcode=1998SSRv...86..563M |s2cid=189791714 |display-authors=et al.}}</ref>