Venera 11

Venera 11
	Seal of Venera 11
Operator	Soviet Academy of Sciences
COSPAR ID	1978-084A; 1978-084D
SATCAT no.	11020; 11027
Mission duration	Travel: 3 months and 16 days; Lander: 95 minutes
Spacecraft properties
Spacecraft	4V-1
Spacecraft type	4V-1 No. 360
Bus	4MV
Launch mass	4,447.3 kg (9,805 lb)
BOL mass	4,715 kg (10,395 lb)
Landing mass	760 kg (1,680 lb)
Dimensions	2.7 m × 2.3 m × 5.7 m (8.9 ft × 7.5 ft × 18.7 ft)
Start of mission
Launch date	September 9, 1978, 03:25:39 UTC
Rocket	Proton-K/D-1 8K82K
Launch site	Baikonur 81/23
End of mission
Last contact	February 1, 1980
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Semi-major axis	6,569 kilometers (4,082 mi)
Eccentricity	0.0312
Perigee altitude	177 kilometers (110 mi)
Apogee altitude	205 kilometers (127 mi)
Inclination	51.5°
Flyby of Venus
Spacecraft component	Venera 11 flight platform
Closest approach	25 December 1978
Distance	~35,000 kilometers (22,000 mi)
Venus lander
Spacecraft component	Venera 11 descent craft
Landing date	25 December 1978, 03:24
Landing site	14°S 299°E / 14°S 299°E (near Phoebe Regio)
	Venera ← Venera 10 Venera 12 →

The Venera 11 (Russian: Венера-11 meaning Venus 11) was a Soviet uncrewed space mission which was part of the Venera program to explore the planet Venus. Venera 11 was launched on 9 September 1978 at 03:25:39 UTC.^[2]

Separating from its flight platform on December 23, 1978 the lander entered the Venus atmosphere two days later on December 25 at 11.2 km/s. During the descent, it employed aerodynamic braking followed by parachute braking and ending with atmospheric braking. It made a soft landing on the surface at 06:24 Moscow Time (03:24 UT) on 25 December after a descent time of approximately 1 hour. The touchdown speed was 7 to 8 m/s.^[3] Information was transmitted to the flight platform for retransmittal to Еarth until it moved out of range 95 minutes after touchdown.^[4] Landing coordinates are 14°S 299°E / 14°S 299°E / -14; 299.^[3]^[5]

^ ^a ^b ^c ^d Siddiqi, Asif A. (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF). The NASA history series (second ed.). Washington, DC: NASA History Program Office. pp. 127–128. ISBN 978-1-62683-042-4. LCCN 2017059404. SP2018-4041.
^ "Venera 11". Archived from the original on 2015-01-21. Retrieved 2012-12-10.
^ ^a ^b "Venera 11 Descent Craft Launch and Orbital Information". NASA Space Science Data Coordinated Archive. Retrieved November 6, 2019.
^ Cite error: The named reference NSSDC-VDC was invoked but never defined (see the help page).
^ "Venera 11 – Detail". Archived from the original on 2019-11-09. Retrieved 2012-12-10.

[siddiqi-1] Siddiqi, Asif A. (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF). The NASA history series (second ed.). Washington, DC: NASA History Program Office. pp. 127–128. ISBN 978-1-62683-042-4. LCCN 2017059404. SP2018-4041.

[ss-v11-2] "Venera 11". Archived from the original on 2015-01-21. Retrieved 2012-12-10.

[Descent-3] "Venera 11 Descent Craft Launch and Orbital Information". NASA Space Science Data Coordinated Archive. Retrieved November 6, 2019.

[NSSDC-VDC-4] Cite error: The named reference NSSDC-VDC was invoked but never defined (see the help page).

[ss-nasa-v11d-5] "Venera 11 – Detail". Archived from the original on 2019-11-09. Retrieved 2012-12-10.

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