파이어니어 금성 다중탐사정: 두 판 사이의 차이

| 주계약자 = [[휴즈 항공기업]]

| 임무유형 = 금성 대기권 탐사정

| 발사체 = [[아틀라스 센타우르]]

| 발사장소 = [[케이프커네버럴 공군 기지]]

| 접근천체 = [[지구]], [[금성]]

| 목표천체 = [[금성]]

| 임무기간 = 4달 1일

| NSSDC-ID = 1978-078A

The bus was targeted to enter the Venusian atmosphere at a shallow entry angle and transmit data until destruction by the heat of atmospheric friction. The objective was to study the structure and composition of the atmosphere down to the surface, the nature and composition of the clouds, the radiation field and energy exchange in the lower atmosphere, and local information on the atmospheric circulation pattern. With no [[heat shield]] or [[parachute]], the bus made upper atmospheric measurements with two instruments, an Ion Mass Spectrometer (BIMS) and a Neutral Mass Spectrometer (BNMS), down to an altitude of about 110 km before disintegrating on December 9, 1978.

 

The spacecraft carried one large and three small atmospheric probes, designed to collect data as they descended into the [[atmosphere of Venus]]. The probes did not carry photographic instruments, and were not designed to survive landing - the smaller probes were not equipped with parachutes, and the larger probe's parachute was expected to detach as it neared the ground. All four probes continued transmitting data until impact, however one survived and continued to transmit data from the surface.

 

[[File:Pioneer Venus Large Probe.jpg|upright|left|thumb|Pioneer Venus Large Probe opens its parachute]]

The Large probe carried seven experiments, contained within a sealed spherical pressure vessel. The science experiments were:

This pressure vessel was encased in a nose cone and aft protective cover. After deceleration from initial atmospheric entry at about {{convert|11.5|km/s}} near the equator on the night side of Venus, a [[parachute]] was deployed at 47 km altitude. The large probe was about {{convert|150|cm}} in diameter and the pressure vessel itself was {{convert|73.2|cm|in|sp=us}} in diameter.

 

[[File:Smallvenusprobe.gif|left|thumb|upright|A small probe (1-antenna, 2-temperature sensor, 3-frontal protection, 4-hermetic container, 5-nephelometer, 6-radiometer)]]

Three identical small probes, around {{convert|0.8|m}} in diameter, were deployed. These probes consisted of spherical pressure vessels surrounded by an aeroshell, but unlike the large probe, they had no parachutes and the aeroshells did not separate from the probes.

* The '''Day probe''' entered well into the day side, and was the only one of the four probes which continued to send radio signals back after impact, for over an hour.

 

The Pioneer Venus Multiprobe was launched by an [[Atlas-Centaur|Atlas SLV-3D Centaur-D1AR]] rocket, which flew from [[Cape Canaveral Air Force Station Space Launch Complex 36|Launch Complex 36A]] at the [[Cape Canaveral Air Force Station]]. The launch occurred at 07:33 on August 8, 1978, and deployed the Multiprobe into [[heliocentric orbit]] for its coast to Venus.

 

 

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