Y
Balloon
The balloons were spherical superpressure types with a diameter of 3.54 m (11.6 ft) and filled with helium. A gondola assembly weighing 6.9 kg (15 lb) and 1.3 m (4 ft 3 in) long was connected to the balloon envelope by a tether 13 m (43 ft) long. Total mass of the entire assembly was 21 kg (46 lb).
The top section of the gondola assembly was capped by a conical antenna 37 cm (15 in) tall and 13 cm (5.1 in) wide at the base. Beneath the antenna was a module containing the radio transmitter and system control electronics. The lower section of the gondola assembly carried the instrument payload and batteries.
The instruments consisted of:
An arm carrying thin-film resistance thermometers and a velocity anemometer. The anemometer consisted of a free-spinning plastic propeller whose spin was measured by LED-photodetector optointerrupters.
A module containing a PIN diode photodetector to measure light levels and a vibrating quartz beam pressure sensor.
A package at the bottom carrying the batteries and a nephelometer to measure cloud density through light reflection.
The small low-power transmitter only allowed a data transmission rate of 2,048 bit/s, though the system performed data compression to squeeze more information through the narrow bandwidth. Nonetheless, the sampling rate for most of the instruments was only once every 75 seconds. The balloons were tracked by two networks of 20 radio telescopes in total back on Earth: the Soviet network, coordinated by the Soviet Academy of Sciences and the international network, coordinated by Centre national d'études spatiales of France (CNES).
The balloons were dropped onto the planet's darkside and deployed at an altitude of about 50 km (31 mi). They then floated upward a few kilometers to their equilibrium altitude. At this altitude, pressure and temperature conditions of Venus are similar to those of Earth, though the planet's winds moved at hurricane velocity and the carbon dioxide atmosphere is laced with sulphuric acid, along with smaller concentrations of hydrochloric and hydrofluoric acid.
The balloons moved swiftly across the night side of the planet into the light side, where their batteries finally died and contact was lost. Tracking indicated that the motion of the balloons included a surprising vertical component, revealing vertical motions of air masses that had not been detected by earlier probe missions.
The balloons were spherical superpressure types with a diameter of 3.54 m (11.6 ft) and filled with helium. A gondola assembly weighing 6.9 kg (15 lb) and 1.3 m (4 ft 3 in) long was connected to the balloon envelope by a tether 13 m (43 ft) long. Total mass of the entire assembly was 21 kg (46 lb).
The top section of the gondola assembly was capped by a conical antenna 37 cm (15 in) tall and 13 cm (5.1 in) wide at the base. Beneath the antenna was a module containing the radio transmitter and system control electronics. The lower section of the gondola assembly carried the instrument payload and batteries.
The instruments consisted of:
An arm carrying thin-film resistance thermometers and a velocity anemometer. The anemometer consisted of a free-spinning plastic propeller whose spin was measured by LED-photodetector optointerrupters.
A module containing a PIN diode photodetector to measure light levels and a vibrating quartz beam pressure sensor.
A package at the bottom carrying the batteries and a nephelometer to measure cloud density through light reflection.
The small low-power transmitter only allowed a data transmission rate of 2,048 bit/s, though the system performed data compression to squeeze more information through the narrow bandwidth. Nonetheless, the sampling rate for most of the instruments was only once every 75 seconds. The balloons were tracked by two networks of 20 radio telescopes in total back on Earth: the Soviet network, coordinated by the Soviet Academy of Sciences and the international network, coordinated by Centre national d'études spatiales of France (CNES).
The balloons were dropped onto the planet's darkside and deployed at an altitude of about 50 km (31 mi). They then floated upward a few kilometers to their equilibrium altitude. At this altitude, pressure and temperature conditions of Venus are similar to those of Earth, though the planet's winds moved at hurricane velocity and the carbon dioxide atmosphere is laced with sulphuric acid, along with smaller concentrations of hydrochloric and hydrofluoric acid.
The balloons moved swiftly across the night side of the planet into the light side, where their batteries finally died and contact was lost. Tracking indicated that the motion of the balloons included a surprising vertical component, revealing vertical motions of air masses that had not been detected by earlier probe missions.
