Ground-based high-resolution astronomical spectroscopy, combined with new innovations in laboratory techniques at low temperatures, has provided strong evidence for the presence of C60+ (ionized Buckminsterfullerene) in the diffuse interstellar medium (ISM). The attribution of two interstellar absorption bands near 0.96 microns to electronic transitions of C60+ became quite widely accepted in 2015, but irrefutable identification of C60+ requires a match between the wavelengths and the strengths of all five absorption features detectable in the laboratory and in space. Although ground-based observations revealed likely absorptions consistent with three weaker bands at 9348, 9365 and 9428 Angstroms, follow-up observations were required to definitively confirm their presence. Using the novel STIS-scanning technique pioneered by our team, we obtained ultra-high signal-to-noise, high-dispersion Hubble Space Telescope spectra of seven heavily reddened interstellar sightlines. A primary benefit of these spectra is that they do not suffer from contamination by telluric absorption that afflicts ground-based observations in this part of the spectrum. We thus obtained reliable detections of the (weak) 9365, 9428 Angstrom and (strong) 9577 Angstrom C60+ bands. Within the uncertainties, the band wavelengths and strength ratios in early B-type stars (suffering from relatively little stellar contamination) were found to match those determined in the latest laboratory experiments of Campbell et al. (2018), so we consider this a robust identification of the 9428 A band, and conclusive confirmation of interstellar C60+.