View source for Zond 6

{{Short description|Unsuccessful 1968 Soviet test spaceflight to the Moon}}
{{Use British English|date=March 2014}}
{{Use dmy dates|date=March 2014}}
{{Infobox spaceflight
| name                  = Zond 6 <!--defaults to page title-->
| names_list            = Soyuz 7K-L1 s/n 12<!--list of previous names if the spacecraft has been renamed. 
Include the dates applicable if possible, and separate each name with a linebreak. 
Omit if the spacecraft has only ever been known by one name. 
Do not include Harvard, COSPAR/NSSDC or SATCAT/NORAD/NASA designations as alternative names-->

<!--image of the spacecraft/mission-->
| image                 = Zond L1 drawing.svg
| image_caption         = <!--image caption-->
| image_alt             = <!--image alt text-->
| image_size            =<!--include px/em; defaults to 220px-->

<!--Basic details-->
| mission_type          = [[Planetary Science]]
| operator              = [[Lavochkin]]
| Harvard_designation   = <!--spacecraft launched 1962 and earlier only (eg. 1957 Alpha 2)-->
| COSPAR_ID             = 1968-101A
| SATCAT                = 03535
| website               = <!--Homepage of the craft/mission, OFFICIAL PAGES ONLY-->
| mission_duration      = {{age in days|1968|11|10|1968|11|17}} days
| distance_travelled    = <!--How far the spacecraft travelled (if known)-->
| orbits_completed      = <!--number of times the spacecraft orbited the Earth - see below for spacecraft beyond Earth orbit-->
| suborbital_range      = <!--downrange distance reached if spacecraft did not enter orbit-->
| suborbital_apogee     = <!--altitude reached if spacecraft did not enter orbit-->

<!--Spacecraft properties-->
| spacecraft            = <!--Spacecraft name/serial number (eg. Space Shuttle ''Discovery'', Apollo CM-118), etc-->
| spacecraft_type       = <!--eg. GPS Block II, Kobalt-M, US-K, etc-->
| spacecraft_bus        = <!--eg. A2100M, Star-2, etc-->
| manufacturer          = NPO Energia Company {{citation needed|date=August 2016}} <!--copied from old infobox, not sure if this is correct, thought NPO was still an OKB design bureau at the time-->
| launch_mass           = {{convert|5375|kg|abbr=on}}<ref name="Zond_6">{{Cite book |last=Siddiqi |first=Asif A. |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 |publisher=NASA History Program Office |year=2018 |edition=second |pages=81–82 |chapter=Zond 6}}</ref>
| BOL_mass              = <!--spacecraft mass in orbit at beginning of operational life, after LEOP phase-->
| landing_mass          = <!--Mass after landing (recovered spacecraft only)-->
| dry_mass              = <!--spacecraft mass in orbit without fuel-->
| payload_mass          = <!--Mass of cargo carried by spacecraft (eg. for Space Shuttle), or total mass of instrumentation/equipment/experiments for mission-->
| dimensions            = <!--body dimensions and solar array span-->
| power                 = <!--end-of-life power, in watts-->

<!--Launch details-->
| launch_date           = {{start date|df=yes|1968|11|10|19|11|31|7=Z}}<ref name=Zond_6/>
| launch_rocket         = [[Proton-K]]/11S824
| launch_site           = [[Baikonur Cosmodrome|Baikonur]] [[Baikonur Cosmodrome Site 81|81/26]]
| launch_contractor     = <!--organisation(s) that conducted the launch (eg. United Launch Alliance, Arianespace, etc)-->
| deployment_from       = <!--place where deployed from-->
| deployment_date       = <!--date deployed-->
| entered_service       = <!--date on which the spacecraft entered service, if it did not do so immediately after launch-->
<!-- * - e.g. Proton-M/Briz-M not Proton-M, but Titan IV(401)A not Titan IV(401)A-Centaur-->

<!--end of mission-->
| disposal_type         = Crash landed
| deactivated           = <!--when craft was decommissioned-->
| destroyed             = <!--when craft was destroyed (if other than by re-entry)-->
| last_contact          = <!--when last signal received if not decommissioned-->
| recovery_by           = <!--recovered by-->
| recovery_date         = <!--date recovered-->
| decay_date            = <!--when craft re-entered the atmosphere, not needed if it landed-->
| landing_date          = {{end date|df=yes|1968|11|17}} 14:10 UT<ref name="Zond_6"/>
| landing_site          = 70 km NE of [[Baikonur Cosmodrome|Tyuratam]], [[Kazakhstan]], [[USSR]]<ref>{{Cite web|url=http://www.russianspaceweb.com/zond6.html|title=Zond-6: Racing Apollo-8|website=www.russianspaceweb.com|access-date=2019-07-29}}</ref>

<!--
    The following template should be used for ONE of the three above fields "end_of_mission", "decay" or "landing" if the spacecraft is no longer operational.
    If it landed intact, use it for the landing time, otherwise for the date it ceased operations, or the decay date if it was still operational when it re-entered.
    {{end date|df=yes|YYYY|MM|DD|hh|mm|ss|TZ=Z}} (for Zulu/UTC) or {{end date|df=yes|YYYY|MM|DD}} (if time unknown) 
-->

<!--orbit parameters-->
<!--as science-related articles, SI units should be the principal units of measurement, however we usually use {{convert}} to display imperial units in parentheses after the initial values-->
| orbit_reference       = <!--geocentric, selenocentric, etc - please link (e.g. [[Geocentric orbit|Geocentric]])-->
| orbit_regime          = <!--high, low, medium, molniya, GSO - please link (e.g. [[Low Earth orbit|Low Earth]] - please don't use acronyms-->
| orbit_longitude       = <!--geosynchronous satellites only-->
| orbit_slot            = <!--Designation of orbital position or slot, if not longitude (e.g plane and position of a GPS satellite)-->
| orbit_semimajor       = <!--semimajor axis-->
| orbit_eccentricity    = <!--orbital eccentricity-->
| orbit_periapsis       = {{convert|120|km|abbr=on}} 
| orbit_apoapsis        = {{convert|400,000|km|abbr=on}} 
| orbit_inclination     = 51.5° 
| orbit_period          = 500 days
| orbit_RAAN            = <!--right ascension of the ascending node-->
| orbit_arg_periapsis   = <!--argument of perigee/periapsis-->
| orbit_mean_anomaly    = <!--mean anomaly at epoch, only use in conjunction with an epoch value-->
| orbit_mean_motion     = <!--mean motion of the satellite, usually measured in orbits per day-->
| orbit_repeat          = <!--repeat interval/revisit time-->
| orbit_velocity        = <!--speed at which the spacecraft was travelling at epoch - only use for spacecraft with low orbital eccentricity-->
| orbit_epoch           = <!--the date at which the orbit parameters were correct-->
| orbit_rev_number      = <!--revolution number-->
| apsis                 = gee

|interplanetary         = <!--Infobox spaceflight/IP can be called multiple times for missions with multiple targets or combined orbiter/lander missions, etc-->
 {{Infobox spaceflight/IP
   |type                = flyby
   |object              = [[Moon]]
   |orbits              = <!--number of orbits completed at target body (if applicable and known)-->
   |component           = <!--part of the spacecraft involved, if spacecraft split into multiple components-->
   |arrival_date        = 14 November 1968
   |departure_date      = <!--Date of leaving orbit for orbiters, date of launch for landers which took off again-->
   |location            = <!--landing/impact site, including EOM impacts for atmospheric probes and lunar/asteroid orbiters-->
   |distance            = {{convert|2,420|km|abbr=on}}
 }}

<!--transponder parameters-->
| trans_band            = <!--Transponder frequency bands-->
| trans_frequency       = <!--specific frequencies-->
| trans_bandwidth       = <!--bandwidth-->
| trans_capacity        = <!--capacity of the transponders-->
| trans_coverage        = <!--area covered-->
| trans_TWTA            = <!--TWTA output power-->
| trans_EIRP            = <!--equivalent isotropic power-->
| trans_HPBW            = <!--half-power beam width-->

<!--Only use where a spacecraft/mission is part of a clear programme of sequential missions. 
If in doubt, leave it out-->
| programme             = [[Zond program|Zond]]
| previous_mission      = [[Zond 5]]
| next_mission          = [[Zond 1969A]]

<!--mission insignia or patch-->
| insignia              = <!--omit the "file" prefix-->
| insignia_caption      = <!--image caption-->
| insignia_alt          = <!--image alt text-->
| insignia_size         = <!--include px/em; defaults to 180px-->

|instruments_list=
 {{Infobox spaceflight/Instruments
  |name1=[[cosmic ray]] and [[micrometeoroid]] detectors
  |name2=photography equipment
  |name3=biological payload
 }}
}}

'''Zond 6''' was a formal member of the Soviet [[Zond program]], and an unpiloted version of the [[Soyuz 7K-L1]] crewed Moon-flyby spacecraft. It was launched on a lunar flyby mission on November 10, 1968, from a parent satellite (68-101B) in Earth parking orbit. The spacecraft carried a biological payload of turtles, flies, and bacteria. It also carried scientific probes including [[cosmic ray]], [[micrometeoroid]] detectors, and photographic equipment.<ref>{{Cite web |title=NASA - NSSDCA - Spacecraft - Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-101A |access-date=2024-01-29 |website=nssdc.gsfc.nasa.gov |archive-date=4 April 2019 |archive-url=https://web.archive.org/web/20190404021615/https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-101A |url-status=dead }}</ref>

The mission was a precursor to a crewed circumlunar flight which the Soviets hoped could occur in December 1968, thus beating the American [[Apollo 8]]. However, after rounding the Moon on November 14, Zond 6 crashed on its return to Earth, due to a parachute failure when the parachute was detached from the capsule too early.

==Mission==
Zond 6 was the official designation for [[Soyuz 7K-L1]] s/n 12. It was supposed to photograph the Moon in colour and in black and white, from 8,000&nbsp;km and 2,600&nbsp;km ranges, then return to Earth, landing at [[Tyuratam]], only 16&nbsp;km from the launch pad. It had been a long and difficult road to develop the L1 guidance system, but it worked perfectly that time.

Zond 6 flew around the Moon on 14 November 1968, at a minimum distance of 2,420&nbsp;km. Photographs of the lunar near side and far side were obtained with [[panchromatic film]]. Each photo was {{convert|5|by|7|in|mm|abbr=on}}. Some of the views allowed for stereo pictures. The photos were taken from distances of approximately 11,000&nbsp;km and 3,300&nbsp;km.

The flight was tracked by [[Jodrell Bank Observatory]], which picked up telemetry data and voice transmissions. The telemetry data appear to have been simulated sensor readings; the voices were either from a tape recorder or being relayed through the probe.<ref name="man" /> In 2018, a recording of the signals was found in Jodrell Bank's archive.<ref name="man">{{Cite web |date=14 November 2018 |title=Jodrell Bank Observatory release 50 year-old audio archive of Soviet Zond 6 lunar mission |url=https://www.manchester.ac.uk/discover/news/jodrell-bank-observatory-release-50-year-old-audio-archive-of-soviet-zond-6-lunar-mission/ |access-date=30 August 2020 |website=manchester.ac.uk |publisher=The University of Manchester}}</ref>

During the craft's return from the Moon, concerns arose about the falling temperatures of the hydrogen peroxide tanks.<ref name="Ulivi203" /> This issue was addressed by rotating Zond 6 so that the tanks were in direct sunlight.<ref name="Ulivi203" /> While this was successful in raising the temperatures of the tanks, it also damaged the seal around the door of the re-entry cabin, resulting in the spacecraft starting to leak and the pressure in the cabin falling.<ref name="Ulivi203">{{Cite book |last1=Ulivi |first1=Paolo |url=https://archive.org/details/lunarexploration0000uliv |title=Lunar Exploration: Human Pioneers and Robot Surveyors |last2=Harland |first2=David M |date=2004 |publisher=Springer |isbn=185233746X |pages=203–204 |url-access=registration}}</ref>

Zond 6 used a relatively uncommon technique called "[[skip reentry]]" to shed velocity upon returning to Earth which limited deceleration forces to 4-7&nbsp;g.<ref name="Zond_6" /> A few hours before reentry, on 17 November 1968, the cabin largely depressurised, killing all the animal test subjects aboard. A further problem resulted in Zond 6's parachutes ejecting while the cabin was still several miles up. The craft crashed in Kazakhstan, near the designated landing area.<ref name=Harvey188>{{cite book |last=Harvey |first=Brian |date=2007 |title=Soviet and Russian Lunar Exploration |publisher=Springer-Praxis |pages=188–190|isbn=978-0387218960}}</ref>

Investigation of the remains of the spacecraft was delayed while the self-destruct system was located and removed.<ref name="Ulivi203" /> The craft's film magazines could then be recovered, and the images therein were published, along with claims that the mission had been entirely successful.<ref name="Ulivi203" /><ref name=Harvey188 />

A State Commission investigating the crash later determined that the [[corona discharge|coronal discharge effect]] which caused the parachute to jettison would only occur at the {{cvt|25|mmHg|kPa}} capsule pressure. If the capsule had been completely depressurised to a high vacuum, the accident would not have occurred.

==Details==
* Launch Date/Time: 1968-11-10 at 19:11:31 UTC
* On-orbit dry mass: 5375&nbsp;kg

{{Clear}}

==See also==
{{Portal|Spaceflight}}
* [[1968 in spaceflight]]
* [[Animals in space]]
* [[Zond 5]], two tortoises who flew to the Moon on the Soviet Union's September 1968 [[Zond 5]] circumlunar flight
* [[Zond 7]], four turtles flew the August 1969 circumlunar flight
* [[Fe, Fi, Fo, Fum, and Phooey]], five mice who orbited the Moon a record 75 times on the December 1972 [[Apollo 17]] mission
* [[List of missions to the Moon]]
{{Clear}}

==References==
<references />

==External links==
* [https://web.archive.org/web/20070202090150/http://astronautix.com/details/zond6810.htm Zond-6 in astronautix.com]
*[https://www.newspapers.com/clip/28995676/the_journal_news/ Zond 6 Heads for Earth Today]
*[https://www.planetary.org/space-images/c_zond06_2 Zond 6 image of Earth] on Bruce Murray Space Image Library

''This article was originally based on material from [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-101A NASA (NSSDC) information on Zond 6] {{Webarchive|url=https://web.archive.org/web/20190404021615/https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-101A |date=4 April 2019 }}''
<!--in that case it probably needs a complete rewrite-->

{{Zond program}}
{{Moon spacecraft}}
{{Orbital launches in 1968}}
{{N1-L3}}
{{Individual turtles}}

[[Category:Missions to the Moon]]
[[Category:Zond program]]
[[Category:1968 in the Soviet Union]]
[[Category:Spacecraft launched in 1968]]
[[Category:Lunar flybys]]
[[Category:Animals in space]]
[[Category:Animal testing in the Soviet Union]]
[[Category:Individual turtles]]