The NASA program of in situ Venus exploration has to date launched only one mission, Pioneer-Venus, launched in 1978. Pioneer-Venus consisted of one Large Probe with a parachute to prolong its descent and three small probes. These probes were designed to operate deep in the atmosphere but there was no requirement for them to survive a landing on Venus. Ultimately, even though they all experienced a number of anomalies in the lower atmosphere, they all operated until surface impact, with one continuing to send data after impact. One Multiprobe Bus carried all probes until they were separated sequentially near Venus to reach different regions. It then entered the atmosphere and obtained atmospheric composition data until burnup. Details about the Pioneer-Venus mission elements and technologies are provided in the report titled Extreme Environment Technologies for Future Space Science Missions.
Pioneer-Venus – USA