# Pioneer Venus Small Probe (Day) > third Small Probe of the Pioneer Venus Multiprobe mission **Wikidata**: [Q113129838](https://www.wikidata.org/wiki/Q113129838) **Source**: https://4ort.xyz/entity/pioneer-venus-small-probe-day ## Summary The Pioneer Venus Small Probe (Day) was an American atmospheric entry probe and lander operated by NASA's Ames Research Center. As the third small probe of the Pioneer Venus Multiprobe mission, it was launched on August 8, 1978, aboard an Atlas SLV-3D Centaur-D1AR vehicle. Weighing 90 kilograms and measuring 0.8 meters in diameter, the spacecraft successfully descended to the surface of Venus on December 9, 1978. ## Key Facts - **Mission Classification:** Instance of a lander; part of the Pioneer Venus Multiprobe mission. - **Launch Date:** August 8, 1978, at 07:33:00 UTC. - **Launch Site:** Cape Canaveral Launch Complex 36 (Atlas SLV-3D Centaur-D1AR, serial AC-51). - **Landing Date:** December 9, 1978 (Spacecraft Event Time: 19:47:59). - **Landing Location:** Venus (Coordinates: -31.3° latitude, 317° longitude). - **Mass and Dimensions:** Mass of 90 kilograms; diameter of 0.8 metres. - **Manufacturer:** Hughes Aircraft Company. - **Operator:** Ames Research Center. - **Identifiers:** COSPAR ID 1978-078G; NSSDCA ID 1978-078G; SCN 12106. ## FAQs ### Q: When did the Pioneer Venus Small Probe (Day) land on Venus? A: The probe landed on Venus on December 9, 1978. The specific Spacecraft Event Time recorded for the landing was 19:47:59. ### Q: What were the physical specifications of the probe? A: The probe had a total mass of 90 kilograms and a diameter of 0.8 metres. It was spherical in shape to withstand the atmospheric pressures of Venus. ### Q: Who manufactured and operated the Pioneer Venus Small Probe (Day)? A: The spacecraft was manufactured by Hughes Aircraft Company and operated by the Ames Research Center in the United States. ### Q: What was the entry timeline for the probe? A: The probe experienced orbit decay (atmospheric entry) on December 9, 1978, at 18:52:18 UTC, approximately one hour before the recorded landing event at 19:47:59 UTC. ## Why It Matters The Pioneer Venus Small Probe (Day) represents a critical component of the United States' intensive exploration of Venus during the late 1970s. As part of the Pioneer Venus Multiprobe mission, this spacecraft contributed to the first extensive, simultaneous sampling of the Venusian atmosphere and surface at different locations. While the larger "Bus" and "Large Probe" often receive more attention, the three small probes (Day, Night, and North) were engineered specifically to survive impact and transmit data from the surface. The "Day" probe provided distinct data sets corresponding to the illuminated side of the planet, allowing scientists to correlate atmospheric dynamics with solar radiation influences. By successfully navigating the descent from orbit decay at 18:52:18 to landing at 19:47:59, the probe demonstrated the durability of Hughes Aircraft Company's design against the extreme pressure and temperature of the Venusian environment. Its specific landing coordinates (-31.3, 317) helped map local variations in the planet's surface conditions. ## Notable For - **Component of a Multiprobe Mission:** Distinguished as the third Small Probe within the broader Pioneer Venus Multiprobe architecture. - **Successful Surface Operations:** Classified distinctly as a "lander" that achieved a recorded stop on the surface, distinct from probes that only perform atmospheric descent. - **Precise Event Logging:** One of the few probes with precise timestamps recorded for both orbit decay (entry) and final landing events down to the second. - **Specific Targeting:** Targeted a specific coordinate on the day side of Venus to complement data gathered by the Night and North probes. ## Body ### Mission Context and Design The Pioneer Venus Small Probe (Day), also known as Pioneer Venus Probe Day or 1978-078G, was a specialized spacecraft designed for in-situ analysis of Venus. Manufactured by Hughes Aircraft Company and managed by the Ames Research Center, the probe had a mass of 90 kg and a structural diameter of 0.8 metres. It was one of four probes released by the Pioneer Venus Multiprobe bus. ### Launch and Transit The probe was launched from Cape Canaveral Launch Complex 36 in the United States. The launch occurred on August 8, 1978, at 07:33:00 UTC, utilizing an Atlas SLV-3D Centaur-D1AR launch vehicle (serial number AC-51). The spacecraft spent approximately four months in transit to its target. ### Descent and Landing The mission's critical phase occurred on December 9, 1978. The probe began its atmospheric entry, identified as the time of object orbit decay, at 18:52:18 UTC. It successfully descended through the atmosphere and landed on the surface of Venus at coordinates latitude -31.3 and longitude 317. The landing event was recorded at 19:47:59 UTC, confirming the probe's function as a surface lander. ## References 1. [Source](https://space.skyrocket.de/doc_sdat/pioneer-13.htm) 2. [Source](https://www.nasa.gov/centers-and-facilities/ames/40-years-ago-pioneers-encounter-venus/) 3. Jonathan's Space Report 4. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1978-078G)