Launch from Cape Canaveral (KSC); landing on Edwards AFB.

ASTRO-2 marked the second flight of three ultraviolet telescopes flown on Astro-1, mounted on Instrument Pointing System on Spacelab pallet in cargo bay. Hopkins Ultraviolet Telescope (HUT), developed at the Johns Hopkins University, performs spectroscopy in far ultraviolet region of spectrum to identify physical processes and chemical composition of a celestial object. Improvements made to HUT after ASTRO-1 made it three times more sensitive. Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE), built at the University of Wisconsin, measures photometry and polarization of ultraviolet radiation from astronomical objects. Ultraviolet Imaging Telescope (UIT), sponsored by NASA's Goddard Space Flight Center, takes wide-field photographs of objects in ultraviolet light.

ASTRO-2 program aimed at exploring 23 different science programs, and all were achieved. HUT, considered complement to Hubble Space Telescope, completed more than 200 separate observations of more than 100 celestial objects. Investigators believed telescope collected enough data to meet its primary mission objective: detecting presence of intergalactic helium, telltale remnant of theoretical Big Bang explosion that began universe. HUT, in conjunction with Hubble telescope, took ultraviolet measurements of Jupiter's aurora; also studied Jupiter's moon Io, and Venusian and Martian atmospheres.

UIT cameras imaged about two dozen large spiral galaxies for inclusion in atlas of such galaxies, and made first ultraviolet images of entire moon. Also studied rare, hot stars that are 100 times as hot as sun; elliptical galaxies and some of faintest galaxies in universe. Investigators were disappointed upon developing UIT film to learn that one of its two cameras had malfunctioned undetected on orbit, but an initial assessment showed that 80 percent of science objectives still would be met.

WUPPE yielded a "treasure chest of data," according to its principal investigator, greatly expanding database on ultraviolet spectropolarimetry. Targets for study of interstellar medium included dust clouds in Milky Way and nearby galaxy, Large Magellanic Cloud. WUPPE also studied several types of stars, including Wolf-Rayet and Be stars. Also able to capitalize on opportunity to study three recently exploding novae.

On the Middeck, science experiments include the Protein Crystal Growth Thermal Enclosure System Vapor Diffusion Apparatus-03 experiment (PCG-TES-03), the Protein Crystal Growth Single Thermal Enclosure System-02 (PCG-STES-02), the Shuttle Amateur Radio Experiment-II (SAREX-II), the Middeck Active Control Experiment (MACE), the Commercial Materials Dispersion Apparatus Instrumentation Technology Associates Experiments-03 (CMIX-03) and the Midcourse Space Experiment (MSX).

The mission was extended one day due of bad weather and so this Shuttle flight became the longest to date.