Camera/Spectrograph (UVC) was flown, the first astronomical observations taken from the Moon, seeking data on hydrogen sources in space without the masking effect of the Earth's corona. The instrument was placed in the LM's shadow and pointed at nebulae, other astronomical objects, the Earth itself, and any suspected volcanic vents seen on the lunar surface. The film was returned to Earth. When asked to summarize the results for a general audience, Dr. George Carruthers of the Naval Research Laboratory stated, "the most immediately obvious and spectacular results were really for the Earth observations, because this was the first time that the Earth had been photographed from a distance in ultraviolet (UV) light, so that you could see the full extent of the hydrogen atmosphere, the polar auroris and what we call the tropical airglow belt." Four panels mounted on the LM's descent stage comprised the Cosmic Ray Detector, designed to record cosmic ray and solar wind particles. Three of the panels were left uncovered during the voyage to the Moon, with the fourth uncovered by the crew early in the EVA. The panels would be bagged for return to Earth. The free-standing Solar Wind Composition Experiment flew on Apollo 16, as it had on each of the lunar landings, for deployment on the lunar surface and return to Earth. Platinum foil was added to the aluminum of the previous experiments, to minimize contamination. Particles and Fields Subsatellite PFS-2 The Apollo 16 Particles and Fields Subsatellite (PFS-2) was a small satellite released into lunar orbit from the service module. Its principal objective was to measure charged particles and magnetic fields all around the Moon as the Moon orbited Earth, similar to its sister spacecraft, PFS-1, released eight months earlier by Apollo 15. The two probes were intended to have similar orbits, ranging from above the lunar surface. Like the Apollo 15 subsatellite, PFS-2 was expected to have a lifetime of at least a year before its orbit decayed and it crashed onto the lunar surface. The decision to bring Apollo 16 home early after there were difficulties with the main engine meant that the spacecraft did not go to the orbit which had been planned for PFS-2. Instead, it was ejected into a lower-than-planned orbit and crashed into the Moon a month later on May 29, 1972, after circling the Moon 424 times. This brief lifetime was because lunar mascons were