Helioseismology with the ACRIM instrument on the Solar Maximum Mission

The Active Cavity Radiometer Irradiance Monitor (ACRIM) instrument on board SMM pioneered high-precision solar photometry from space, and provided the first detection of solar p-mode oscillations at low degree by this technique. The observations extended from February, 1980, until December, 1989, with a hiatus of low sampling rate in 1981-1984. During summer 1989, the instrument operated in a 'no-shutter' mode with continuous viewing between the orbital gaps. This resulted in a fourfold increase of the duty cycle, and an effective increase in the Nyquist frequency from 3.815 mHz to some tens of mHz. This review discusses the initial results from this campaign along with a general review of the analyses to date of the entire ACRIM data set.