Venera 15

Venera 15

Mission type	Venusorbiter
Operator	Soviet Academy of Sciences
COSPAR ID	1983-053A
SATCATno.	14104
Mission duration	Overall: 1 year, 1 month, 7 days At Venus: 9 months
Spacecraft properties
Spacecraft type	4V-2No. 860
Manufacturer	NPO Lavochkin
Launch mass	5,250 kg (11,570 lb)
Dry mass	4,000 kg (8,800 lb)
Start of mission
Launch date	June 2, 1983, 02:38:39(1983-06-02UTC02:38:39)UTC
Rocket	Proton-K/D-1
Launch site	Baikonur200/39
End of mission
Last contact	January 5, 1985(1985-01-06)
Orbital parameters
Reference system	Cytherocentric
Semi-major axis	38,848 kilometres (24,139 mi)
Eccentricity	0.8211
Pericytherion altitude	7,081 kilometres (4,400 mi)
Apocytherion altitude	72,079 kilometres (44,788 mi)
Inclination	92.5 degrees
Period	24 hours
Epoch	October 9, 1983(1983-10-09)
Venusorbiter
Orbital insertion	October 10, 1983
Orbits	260
Venera

Venera 15(Russian:Венера-15meaningVenus 15) was aspacecraftsent toVenusby theSoviet Union.This uncrewed orbiter was to map the surface of Venus using high resolution imaging systems. The spacecraft was identical toVenera 16and based on modifications to the earlierVeneraspace probes.

Mission profile

Flight profile of Venera 15

Venera 15 was launched on June 2, 1983, at 02:38:39UTCand reached Venus' orbit on October 10, 1983.

The spacecraft was inserted into Venus orbit a day apart from Venera 16, with its orbital plane shifted by an angle of approximately 4° relative to the other probe. This made it possible to reimage an area if necessary. The spacecraft was in a nearly polar orbit with aperiapsis~1000 km, at 62°N latitude, andapoapsis~65000 km, with aninclination~90°, the orbital period being ~24 hours.

Together with Venera 16, the spacecraft imaged the area from the north pole down to about 30°N latitude (approximately 25% of Venus surface) over the eight months of mapping operations.

Spacecraft structure

The Venera 15 and 16 spacecraft were identical and were based on modifications to theVenera 9orbiter and theVenera 14carrier spacecraft. Each spacecraft consisted of a 5 m (16 ft) long cylinder with a 0.6 m (2.0 ft) diameter, 1.4 m (4.6 ft) tall parabolic dish antenna for thesynthetic aperture radar(SAR) at one end. A 1-meter diameter parabolic dish antenna for the radio altimeter was also located at this end. The electrical axis of the radio altimeter antenna was lined up with the axis of the cylinder. The electrical axis of the SAR deviated from the spacecraft axis by 10 degrees. During imaging, the radio altimeter would be lined up with the center of the planet (local vertical) and the SAR would be looking off to the side at 10 degrees. A bulge at the opposite end of the cylinder held fuel tanks and propulsion units. Two square solar arrays extended like wings from the sides of the cylinder. A 2.6 m (8.5 ft) radio dish antenna for communications was also attached to the side of the cylinder. The spacecraft each massed 4,000 kg (8,800 lb).

Both Venera 15 and 16 were equipped with asynthetic-aperture radar(SAR). Aradarwas necessary in this mission because nothing else would be able to penetrate the dense clouds of Venus. The probes were equipped with on board computers that saved the images until the entire image was complete. This radar system replaced the normal landers that previous Venera probes brought to Venus.

List of spacecraft instruments and experiments:

• Polyus-V Synthetic Aperture Radar
• OmegaRadar altimeter
• Infrared Fourier Spectrometer
• Cosmic-Ray Detectors (6 sensors)
• Solar-Plasma Detectors

To get to Venus, Venera 15 was placed in aheliocentric orbitwithperihelionof 0.71 AU,apohelionof 1.01 AU,eccentricityof 0.17,orbital inclinationof 2.3 degrees andorbital periodof 293 days.

See also

• List of missions to Venus

External links

• The Soviet Exploration of Venus
• Catalog of Soviet Venus images
• Venera 15/16 Radar Mosaic Browser