The NASA advanced composition explorer (ACE) was launched in august 1997 and was subsequently put into orbit at the L1 point between the earth and the sun. The johns hopkins university applied physics…

This is a $2,005,622.43 grant awarded by NASA to The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to continue operating the Electron, Proton and Alpha Monitor (EPAM) and Ultra-Low Energy Isotope Spectrometer (ULEIS) instruments on the Advanced Composition Explorer (ACE) mission. ACE was launched in 1997 to study the composition of the solar corona, interplanetary medium, local interstellar medium, and galactic matter. The grant, which started on November 1, 2016, provides funding for instrument operations and data analysis. There is no set-aside designation for this award. JHU/APL has been the prime contractor responsible for the EPAM and ULEIS instruments since the ACE mission began.

The NASA advanced composition explorer (ACE) was launched in august 1997 and was subsequently put into orbit at the L1 point between the earth and the sun. The johns hopkins university applied physics laboratory (JHU/APL) was chosen by NASA to develop and operate the electron, proton and alpha monitor (epam) instrument and the ultra-low energy isotope spectrometer (uleis) instrument (in conjunction with the university of maryland) for this mission. That effort included NASA phase c/d responsibility for development, test, qualification, calibration, spacecraft integration and initial spaceflight mission operations and scientific data analyses for the uleis and epam instruments. Launch occurred on august 25, 1997 with formal phase c/d efforts extending through january 31, 1998. During november 1997, covers for both epam and uleis were deployed, high voltages enabled and both instruments set into operational configuration. In 1998, JHU/APL continued with its uleis and epam responsibilities for instrument mission operations and data analysis under NASA prime contract NAS5- 97271, task order #009. Per this proposal and technical plan, these efforts are to continue under a NASA three-year grant, starting 1 november 2016. The ACE objectives are to study particle populations of the solar system and galactic origins with the prime objective to determine and compare the elemental and isotopic composition of several distinct samples of matter, including the solar corona, the interplanetary medium, the local interstellar medium, and galactic matter. Epam, the electron, proton, and alpha monitor for the ACE mission, consists of 5 solid-state detector systems that provide full unit sphere coverage of ions and electrons in the very rich environment that covers the transition from interplanetary dominated phenomena at low energies to solar events at higher energies. Epam measures electrons from 38 KEV through 315 KEV (from 0.3C 0.78C), and ions from 45 KEV to ~ 5 MEV. Epam also measures i KEV protons through a few MEV/nucleon iron. Uleis, the ultra low energy isotope spectrometer particle instrument on the ACE spacecraft, is studying the elemental and isotopic composition of solar energetic particles, and the mechanisms by which these particles are energized in the solar corona. Uleis is a high resolution mass spectrometer designed to measure particle composition and energy spectra of elements he - NI with energies from ~45 KEV/nucleon to a few MEV/nucleon. The instrument measures particle mass and energy using the time-of-flight VS. Residual energy method. Particles accelerated in solar energetic particle events, interplanetary shocks, and corotating interaction region is being investigated. Uleis, which began operating with full high voltage on september 25, 1997, will also investigate mechanisms by which supersonic interplanetary shock waves energize ions. Uleis is making new observations of heavy ions from impulsive solar flares that will help determine not only how the ions are accelerated but also how they propagate from the sun to earth. The energy source for an impulsive flare is probably the solar magnetic field, although the details of how the energy gets transferred from the magnetic field into particle and photon emissions are still unknown. We do know that these impulsive events have characteristic abundances that distinguish them from any other sample of accelerated matter in the heliosphere: the rare isotope 3HE is enhanced by factors of ~100 to 1000 over its abundance in the sun, and heavy ions are enhanced by factors of ~3 to 10 over their solar abundances. Resonant absorption of waves produced by beams of energetic electrons may be the cause of the peculiar composition enrichments.