View source for Venera 9

{{Short description|1975 Soviet uncrewed space mission to Venus}}
{{Use mdy dates|date=March 2020}}
{{Infobox spaceflight
| name               = Venera 9
| image              = File:Venera 9 Space Probe 01.jpg
| image_size         = 
| image_caption      = Model of Venera 9 lander
| insignia           = File:1984 CPA 5560.jpg
| insignia_size      = 120px
| insignia_caption   = Stamp of Venera 9
| mission_type       = [[Venus]] orbiter / lander
| operator           = [[Lavochkin]]
| COSPAR_ID          = 1975-050A<br/>1975-050D
| SATCAT             = 7915<br/>8411
| mission_duration   = Orbiter: {{time interval|20 October 1975|26 March 1976|show=d}} <br /> Lander: {{time interval|22 October 1975 05:13|22 October 1975 06:06|show=hm}} <br/> Launch to last contact: 292 days
| spacecraft         = [[4MV|4V-1]] No. 660
| manufacturer       = [[Lavochkin]]
| dry_mass           = 
| launch_mass        = {{convert|4936|kg|lb|abbr=on}}<ref name=Venera_9>{{cite book|url=https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf|title=Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016|last1=Siddiqi|first1=Asif|publisher=NASA History Program Office|edition=second|year=2018}}</ref>
| landing_mass       = {{convert|3440|lb|kg|0|order=flip|abbr=on}}
| payload_mass       = {{convert|1455|lb|kg|0|order=flip|abbr=on}}
| power              = <!-- [[watt]]s -->
| launch_date        = {{nowrap| {{start-date|June 8, 1975, 02:38}}&nbsp;UTC<ref name="LL"/> }}
| launch_rocket      = [[Proton-K]]/[[Blok D|D]]<ref name="LL">{{cite web |url=http://planet4589.org/space/log/launchlog.txt |title=Launch Log |first=Jonathan |last=McDowell |website=Jonathan's Space Page |access-date=April 11, 2013}}</ref>
| launch_site        = [[Baikonur Cosmodrome|Baikonur]] [[Baikonur Cosmodrome Site 81|81/24]]
| last_contact       = Orbiter primary mission: {{end-date|March 22, 1976}}<ref>{{cite book|url=https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf|title=Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016|pages=127–128|last1=Siddiqi|first1=Asif A.|lccn=2017059404|isbn=978-1-62683-042-4|publisher=NASA History Program Office|edition=second|year=2018|id=SP2018-4041|series=The NASA history series|location=Washington, DC}}</ref> <br /> Lander: {{end-date|October 22, 1975}}
| orbit_epoch        = 
| orbit_reference    = [[Cytherocentric orbit|Cytherocentric]]
| orbit_periapsis    = {{convert|7625|km|mi|abbr=on}}
| orbit_apoapsis     = {{convert|118072|km|mi|abbr=on}}
| orbit_inclination  = 29.5&nbsp;degrees
| orbit_eccentricity = 0.89002
| orbit_period       = 48.3&nbsp;hours
| apsis              = cytherion
| interplanetary     = {{Infobox spaceflight/IP
   |type                = orbiter
   |object              = [[Venus]]
   |orbits              = 
   |component           = Orbiter
   |arrival_date        = October 20, 1975
 }}
 {{Infobox spaceflight/IP
   |type                = lander
   |object              = [[Venus]]
   |component           = [[Lander (spacecraft)|Lander]]
   |arrival_date        = October 22, 1975, 05:13&nbsp;UTC
   |location            = {{Venus coords and quad cat|31.01|N|291.64|E}}<br/>(near [[Beta Regio]])
 }}
| programme          = [[Venera program|Venera]]
| previous_mission   = [[Kosmos 482]]
| next_mission       = [[Venera 10]]
}}

'''Venera 9''' ({{langx|ru|Венера-9|lit=Venus-9}}), manufacturer's designation: '''4V-1 No. 660''',<ref>{{cite web|url=http://www.russianspaceweb.com/venera75.html|title=History of the Venera 75 project|website=RussianSpaceWeb.com}}</ref> was a [[Soviet Union|Soviet]] [[Uncrewed spacecraft|uncrewed space mission]] to [[Venus]]. It consisted of an orbiter and a lander. It was launched on June 8, 1975, at 02:38:00&nbsp;[[Coordinated Universal Time|UTC]] and had a mass of {{convert|4936|kg|lb}}.<ref>{{cite web |title=Venera 9 |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1975-050A |website=NASA Space Science Data Coordinated Archive|access-date=April 13, 2013}}</ref> The orbiter was the first spacecraft to [[Cytherocentric orbit|orbit Venus]], while the lander was the first to return images from the surface of another planet.<ref>{{cite web|url=http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=3563|title=Solar System Exploration Multimedia Gallery: Venera 9|archive-url=https://web.archive.org/web/20090803180528/http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=3563|archive-date=August 3, 2009|website=NASA|url-status=dead|access-date=August 7, 2009}}</ref>

==Orbiter==
{{more citations needed|section|date=October 2017}}<!--2 paragraphs have no citations-->
The orbiter entered Venus orbit on October 20, 1975. Its mission was to act as a communications relay for the lander and to explore cloud layers and atmospheric parameters with several instruments and experiments. It performed 17 survey missions from October 26, 1975, to December 25, 1975.

The orbiter consisted of a cylinder with two [[solar panel]] wings and a high gain parabolic antenna attached to the curved surface. A bell-shaped unit holding propulsion systems was attached to the bottom of the cylinder, and mounted on top was a {{convert|2.4|m|ft|adj=on}} sphere which held the lander.

===Orbiter design===
The instruments composing the orbiter included:<ref name=Mitchell_Venus>{{cite web |last=Mitchell |first=Don P. |title=First Pictures of the Surface of Venus |url=http://mentallandscape.com/V_Lavochkin2.htm |access-date=April 13, 2013}}</ref>
* 1.6–2.8 [[Micrometre|μm]] IR [[spectrometer]]
* 8–28&nbsp;μm IR radiometer
* 352&nbsp;nm UV photometer
* 2 photo-[[polarimeter]]s (335–800&nbsp;nm)
* 300–800&nbsp;nm spectrometer
* Lyman-α (alpha) H/D spectrometer
* Bistatic radar mapping
* CM, DM radio occultations
* Triaxial [[Magnetometer]]
* 345–380&nbsp;nm [[Ultraviolet|UV]] camera
* 355–445&nbsp;nm camera
* 6 electrostatic analyzers
* 2 modulation [[ion trap]]s
* Low-energy [[proton]] / [[Alpha particle|alpha]] detector
* Low-energy [[electron]] detector
* 3 [[semiconductor]] counters
* 2 gas-discharge counters
* [[Cherenkov detector]]

==Lander==
[[File:Foto de Venera 9.png|440px|thumb|First view and clear image of the surface of Venus, taken by the Venera 9 lander on October 22, 1975]]
[[File:USSR Venera 9 1975 Venus ground colorized by Don P. Mitchell.png|440px|thumb|Digitally reprocessed image of the surface]]
The lander was encased in a spherical shell before landing to help protect it from the heat of entry as it slowed from {{convert|10.7|km/s}} to {{convert|150|m/s}}.  This sphere was then separated with explosive bolts and a three-domed parachute was deployed which slowed the lander further to {{convert|50|m/s}} at an altitude of {{convert|63|km}} above the planet.<ref name=keldysh>Keldysh, M. V., 1977: "Venus Exploration with the Venera 9 and Venera 10 Spacecraft", Icarus, '''30''': 605-625.</ref>

The descent through the cloud layer took about 20 minutes, during which time the lander took measurements of the atmosphere and radioed the information to the orbiter.<ref name="keldysh" />  To minimize lander damage in the hot atmosphere, the parachute was released at an altitude of {{convert|50|km}}, and the ring-shaped aerodynamic shield provided braking.  The Venusian atmosphere is so dense near the surface that this shield provided a descent rate of {{convert|7|m/s}} as the lander touched down.<ref name="keldysh" />  The landing device, a hollow ring surrounding the lower part of the lander, was partly crushed upon touchdown to take up most of the landing impact.<ref name="keldysh" />

On October 20, 1975, the lander spacecraft separated from the orbiter, and landing was made with the [[Sun]] near zenith at 05:13&nbsp;UTC on October 22. ''Venera 9'' landed within a {{convert|150|km|mi|abbr=on}} radius of {{Venus coords and quad cat|31.01|N|291.64|E}}, near [[Beta Regio]], on a steep (20°) slope covered with boulders (suspected to be the slope of the [[tectonic]] [[rift]] valley, [[Aikhulu Chasma|Aikhylu Chasma]]). The entry sphere weighed {{convert|3440|lb|kg|0|order=flip|abbr=on}} and the surface payload was {{convert|1455|lb|kg|0|order=flip|abbr=on}}.<ref>{{Cite web |title=Planetary Spacecraft |url=http://www.braeunig.us/space/planet.htm |access-date=2025-10-10 |website=www.braeunig.us}}</ref>

It was the first spacecraft to return an image from the surface of another planet.  Many of the instruments began working immediately after touchdown and the cameras were operational 2 minutes later.  These instruments revealed a smooth surface with numerous stones.  The lander measured a light level of 14,000 lux, similar to that of Earth in full daylight but no direct sunshine.<ref name="keldysh" />

A system of circulating fluid was used to distribute the heat load. This system, plus pre-cooling prior to entry, permitted operation of the lander for 53 minutes after landing, at which time radio contact with the orbiter was lost as the orbiter moved out of radio range.<ref name=Mitchell_Venus/> During descent, heat dissipation and deceleration were accomplished sequentially by protective hemispheric shells, three parachutes, a disc-shaped drag brake, and a compressible, metal, doughnut-shaped landing cushion. The landing was about {{convert|2200|km|mi|abbr=on}} from the ''[[Venera 10]]'' landing site.

''Venera 9'' measured clouds that were {{convert|30|-|40|km|mi|abbr=on}} thick, with bases at {{convert|30|-|35|km|mi|abbr=on}} altitude. It also measured atmospheric chemicals including [[hydrochloric acid]], [[hydrofluoric acid]], [[bromine]] and [[iodine]]. Other measurements included surface pressure of about {{convert|90|atm|kPa|order=flip|lk=on}}, temperature of {{convert|905|F|C|order=flip|lk=on}}, and surface light levels comparable to those at [[Earth]] mid-latitudes on a cloudy summer day. ''Venera 9'' was the first probe to send back television pictures (black and white) from the Venusian surface, showing no shadows, no apparent dust in the air, and a variety of {{convert|30|to|40|cm|in|abbr=on}} rocks which were not eroded. Planned 360-degree panoramic pictures could not be taken because one of two camera lens covers failed to come off, limiting pictures to 180 degrees. This failure recurred with ''Venera 10''.

===Lander payload===
The lander payload was as follows:<ref name=Mitchell_Venus/>
* Temperature and pressure sensors
* [[Accelerometer]]
* Visible / IR [[photometer]] – IOV-75
* Backscatter and multi-angle [[nephelometer]]s – MNV-75
* P-11 [[mass spectrometer]] – MAV-75
* Panoramic [[Transmissometer|telephotometers]] (2, with lamps)
* [[Anemometer]] – ISV-75
* [[Gamma-ray spectrometer]] – GS-12V
* Gamma-ray [[densitometer]] – RP-75

==See also==
{{commons category|Venera 9}}
{{Portal|Spaceflight}}
* [[List of missions to Venus]]
* [[Timeline of artificial satellites and space probes]]

==References==
{{Reflist}}

{{Venus}}
{{Venera}}
{{Venus spacecraft}}
{{Orbital launches in 1975}}

{{DEFAULTSORT:Venera 09}}
[[Category:Venera program]]
[[Category:1975 in spaceflight]]
[[Category:1975 in the Soviet Union]]
[[Category:Derelict landers (spacecraft)]]
[[Category:Spacecraft launched in 1975]]
[[Category:4MV]]
[[Category:Non Earth orbiting satellites of the Soviet Union]]