The Extreme-Ultraviolet Explorer (EUVE) was a spinning spacecraft designed to rotate about the earth/sun line. EUVE was a part of NASA's Explorer spacecraft series, and designed to operate in the extreme ultraviolet (EUV) range of the spectrum, from 70 - 760 Angstroms. This spacecraft's objective was to carry out a full-sky survey, and subsequently, a deep-survey and pointed observations. Science objectives included discovering and studying UV sources radiating in this spectral region, and analyzing effects of the interstellar medium on the radiation from these sources.
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 variants ("Light" and "Heavy"). The rocket flew its final mission ICESat-2 on 15 September 2018, earning the launch vehicle a streak of 100 successful missions in a row, with the last failure being GPS IIR-1 in 1997.