isotopes of both solar and interstellar sources. SWICS also measured the distribution functions of both the interstellar cloud and dust cloud pickup ions up to energies of 100 keV/e−1. SWIMS measures the chemical, isotopic and charge state composition of the solar wind for every element between He and Ni. Each of the two instruments are time-of-flight mass spectrometers and use electrostatic analysis followed by the time-of-flight and, as required, an energy measurement. On 23 August 2011, the SWICS time-of-flight electronics experienced an age- and radiation-induced hardware anomaly that increased the level of background in the composition data. To mitigate the effects of this background, the model for identifying ions in the data was adjusted to take advantage of only the ion energy-per-charge as measured by the electrostatic analyzer, and the ion energy as measured by solid-state detectors. This has allowed SWICS to continue to deliver a subset of the data products that were provided to the public prior to the hardware anomaly, including ion charge state ratios of oxygen and carbon, and measurements of solar wind iron. The measurements of proton density, speed, and thermal speed by SWICS were not affected by this anomaly and continue to the present day. Ultra-Low-Energy Isotope Spectrometer (ULEIS) The Ultra-Low-Energy Isotope Spectrometer (ULEIS) on the ACE spacecraft is an ultra-high-resolution mass spectrometer that measures particle composition and energy spectra of elements He–Ni with energies from ~45 keV/nucleon to a few MeV/nucleon. ULEIS investigates particles accelerated in solar energetic particle events, interplanetary shocks, and at the solar wind termination shock. By determining energy spectra, mass composition, and temporal variations in conjunction with other ACE instruments, ULEIS greatly improves our knowledge of solar abundances, as well as other reservoirs such as the local interstellar medium. ULEIS combines the high sensitivity required to measure low particle fluxes, along with the capability to operate in the largest solar particle or interplanetary shock events. In addition to detailed information for individual ions, ULEIS features a wide range of count rates for different ions and energies that allows accurate determination of particle fluxes and anisotropies over short (few minutes) time scales. Science results The spectra of particles observed by ACE Figure 1 shows the particle fluence (total flux over a given period of time) of oxygen at ACE for a time period just after solar minimum, the part of the 11-year solar cycle when solar activity is lowest. The lowest-energy