Editing Phobos 1

{{Use dmy dates|date=May 2020}}
{{short description|Soviet mars probe}}
{{italic title}}
{{Infobox spaceflight
| name                  = ''Phobos 1''
| names_list            = <!--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                 = [[File:Phobos Marte.jpg|300px]]
| image_caption         = Illustration of the ''Phobos 1'' spacecraft
| image_alt             = <!--image alt text-->
| image_size            = <!--include px/em; defaults to 220px-->

<!--Basic details-->
| mission_type          = <!--eg. Technology, Reconnaissance, ISS assembly, etc-->
| operator              = [[Russian Space Research Institute|IKI]]
| Harvard_designation   = <!--spacecraft launched 1962 and earlier only (eg. 1957 Alpha 2)-->
| COSPAR_ID             = 1988-058A
| SATCAT                = 19281
| website               = [http://www.iki.rssi.ru/IPL/phobos.html Phobos Mission]
| mission_duration      = <!--How long the mission lasted-->
| 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          = <!--company or companies who built the satellite-->
| launch_mass           = {{convert|6220|kg|lb|abbr=on}}
| 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|1988|07|07|17|38|04|7=Z|df=y}}
| launch_rocket         = [[Proton rocket|Proton-K]] 8K82K/D-1
| launch_site           = [[Baikonur Cosmodrome|Baikonur]] [[Baikonur Cosmodrome Site 200|Site 200/40]]
| 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         = <!--Whether the spacecraft was deorbited, decommissioned, placed in a graveyard orbit, etc-->
| 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         = <!--recovery date-->
| decay_date            = <!--when craft re-entered the atmosphere, not needed if it landed-->
| landing_date          = <!--when the spacecraft made a controlled landing, not needed if it did not return intact-->
| landing_site          = <!--where the craft landed; site/runway or coordinates-->
<!--
    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|YYYY|MM|DD|hh|mm|ss|TZ=Z}} (for Zulu/UTC) or {{end date|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       = [[Areocentric orbit|Areocentric]]
| 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       = <!--periapsis altitude-->
| orbit_apoapsis        = <!--apoapsis altitude-->
| orbit_inclination     = <!--orbital inclination-->
| orbit_period          = <!--time taken to complete an orbit-->
| 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           = planned
| orbit_rev_number      = <!--revolution number-->
| apsis                 = <!--planet specific apsis term (eg. gee/helion/selene/etc – defaults to generic "apsis")-->

|interplanetary         = <!--Infobox spaceflight/IP can be called multiple times for missions with multiple targets or combined orbiter/lander missions, etc-->

<!--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             = [[Phobos program]]
| previous_mission      =
| next_mission          = [[Phobos 2]]

<!--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-->
}}

[[File:Phobos edit 2.jpg|thumb|Phobos was the primary object of study for the ''Phobos 1'' spacecraft.]]
'''''Phobos 1''''' was an uncrewed Soviet space probe of the [[Phobos program|Phobos Program]] launched from the [[Baikonur Cosmodrome|Baikonour]] launch facility on 7 July 1988.<ref>{{Cite book|title=Soviet Robots in the Solar System|last1=Wesley|first1=Huntress|last2=Marov|first2=Mikhail|publisher=Praxis Publishing|year=2011|isbn=978-1-4419-7897-4|location=Chichester, UK|pages=368}}</ref> Its intended mission was to explore [[Mars]] and its moons [[Phobos (moon)|Phobos]] and [[Deimos (moon)|Deimos]]. The mission failed on 2 September 1988 when a computer malfunction caused the end-of-mission order to be transmitted to the spacecraft. At the time of launch it was the heaviest interplanetary spacecraft ever launched, weighing {{val|6200|u=kg}}.<ref name=Harvey251>{{cite book |last=Harvey |first=Brian |date=2007 |title=Russian Planetary Exploration History, Development, Legacy and Prospects  |publisher=Springer-Praxis |page=251 |isbn=9780387463438}}</ref>

==Background==

The intent to carry out a mission with Phobos as the target was first made public 14 November 1984.<ref name=Harvey246 /> Phobos was chosen as the target in order to avoid directly competing with previous American missions.<ref name=Harvey246 /> Originally a 1986 launch was planned but this later moved to 1988.<ref name=Harvey246>{{cite book |last=Harvey |first=Brian |date=2007 |title=Russian Planetary Exploration History, Development, Legacy and Prospects  |publisher=Springer-Praxis |page=246 |isbn=9780387463438}}</ref>

== Flight plan ==
It was to take an estimated 200 days for the ''Phobos 1'' space probe to travel from the [[Earth]] to Mars. Two mid-course corrections were planned, the first between days 7 and 20, and the second between days 185 and 193. These corrections would place the probe in a highly [[Elliptic orbit|elliptical orbit]] around Mars. Next, it was to move into an almost circular observation orbit at 350&nbsp;km. After achieving observation orbit the lower stage of the propulsion system would be dropped. The probe would then rendezvous with Phobos, drop a lander containing scientific equipment from an altitude of 50 meters, and move into a final [[Non-inclined orbit|equatorial orbit]] above Mars where it would study the Martian surface and atmosphere.<ref>{{Cite book|title=Russian Planetary Exploration|last=Harvey|first=Brian|publisher=Praxis Publishing|year=2007|isbn=978-0-387-46343-8|location=Chichester, UK|pages=246–248}}</ref>

== Mission objectives ==
The ''Phobos 1'' probe's scientific study was separated into three phases. In stage one the probe would investigate the [[Sun]] and [[Outer space|interplanetary space]] while traveling from the Earth to Mars. In stage two the probe would study Mars and Phobos while in orbit around Mars. During the final stage it would approach to within 50 meters of the Phobos surface while conducting several experiments.<ref>{{Cite journal|last1=Sagdeev|first1=R. Z.|last2=Zakharov|first2=A. V.|date=19 October 1989|title=Brief History of the Phobos Mission|journal=Nature|volume=341|issue=6243|pages=581–585|doi=10.1038/341581a0|bibcode=1989Natur.341..581S|s2cid=41464654}}</ref>

== Experiments ==
The Phobos probe carried several scientific experiments. It carried a radar transmitter, X-ray and alpha-backscatter spectrometers, camera, and a laser that could vaporize tiny spots so a reflector could analyze the vapor for atomic masses.<ref>{{Cite journal|last=Eberhart|first=Jonathan|date=18 June 1988|title=Phobos: Mission to a Martian Potato|journal=Science News|volume=133|issue=25|pages=392–393|doi=10.2307/3972561|jstor=3972561|bibcode=1988SciN..133..392E|issn=0036-8423}}</ref>

The probe also carried a {{em|hopper}}. The hopper would be dropped onto Phobos to drill and analyze the soil. It would be able to bounce across the terrain by using spring loaded legs.<ref>{{Cite journal|date=16 July 1988|title=Two for Phobos|journal=Science News|volume=134|issue=3|issn=0036-8423}}</ref>

==Mission profile==

The optical [[coronagraph]] that was part of the Terek experiment and  designed to observe the Sun was non-functional from launch.<ref name=Valníček />

=== Malfunction ===
On 2 September 1988, the expected transmission from ''Phobos 1'' was not received. This was traced to a faulty key-command that was sent on 28 August from ground control in [[Yevpatoria]]. Same as the case of [[Mariner 1]], a technician unintentionally left out a single hyphen in one of the keyed commands. All commands were supposed to be proofread by a computer before being transmitted, but the computer that checked code was malfunctioning. The technician violated procedure and transmitted the command before the computer could be fixed to proofread it.<ref>{{Cite journal|date=7 November 1988|title=Phobos-1 Revival Attempts Abandoned|journal=Aviation Week and Space Technology|publisher=Penton Media|volume=129|issue=19|id={{ProQuest|205980638}}}}{{Subscription required|via=[[ProQuest]]}}</ref> This minor alteration in code deactivated the [[Spacecraft attitude control|attitude thrusters]]. By losing its lock on the Sun, the spacecraft could no longer properly orient its solar arrays, thus depleting its batteries.<ref>{{Cite book|title=Soviet Robots in the Solar System |last1=Huntress|first1=Wesley|last2=Marov|first2=Mikhail|publisher=Praxis Publishing|year=2011|isbn=978-1-4419-7897-4|location=Chichester, UK|pages=380}}</ref><ref name=ScienceMag>{{cite journal |last1=WALDROP |first1=M. M. |title=Phobos at Mars: A Dramatic View—and Then Failure |journal=Science |date=8 September 1989 |volume=245 |issue=4922 |pages=1044–1045 |doi=10.1126/science.245.4922.1044 |pmid=17838799 |url=http://catless.ncl.ac.uk/Risks/9.24.html#subj3 |access-date=24 September 2018|url-access=subscription }}</ref>

Software instructions to turn off the probe's attitude control, normally a fatal operation, were part of a routine used when testing the spacecraft on the ground.  Normally this routine would be removed before launch.  However, the software was coded in [[Programmable read-only memory|PROM]]s, and so removing the test code would have required removing and replacing the entire computer.  Because of time pressure from the impending launch, engineers decided to leave the command sequence in, though it should never be used.  However, a single-character error in constructing an upload sequence resulted in the command executing, with subsequent loss of the spacecraft.{{r|ScienceMag}}

The error is also attributed to a political argument between Yevpatoria and Moscow over who should control the mission. Moscow won control responsibility, but Yevpatoria would be responsible for checking all transmitted commands. This further complicated the process of transmitting valid commands to the spacecraft.<ref>{{Cite book|title=Russian Planetary Exploration|last=Harvey|first=Brian|publisher=Praxis Publishing|year=2007|isbn=978-0-387-46343-8|location=Chichester, UK|pages=251}}</ref>

== Subsequent investigation ==
After the incident at Yevpatoria, an investigation was immediately ordered to determine who was responsible for the failure. Nevertheless, disciplinary action was postponed until the completion of the ''[[Phobos 2]]'' mission. This was to prevent the demoralization of the ''Phobos 2'' team. Any penalization of the ''Phobos 1'' team would create anxiety among the ''Phobos 2'' team and reduce the chances of mission success. This postponement of punitive measures was urged by IKI director Roald Sagdeev. He quoted the former secret-service chief under [[Stalin]], [[Lavrenti Beria]], who said, "Let's make them work for now. We can shoot them all later." The investigation concluded with the dismissal of the ground control commander at Yevpatoria and the acknowledgement that the computer system was poorly designed.<ref>{{Cite book|title=Russian Planetary Exploration|last=Harvey|first=Brian|publisher=Praxis Publishing|year=2007|isbn=978-0-387-46343-8|location=Chichester, UK|pages=251–252}}</ref>

==Results==
The probe observed the Sun in both X-rays (0.5–2.5 nm) and [[extreme ultraviolet]] (17–18 nm).<ref name=Valníček /> On 27 August a solar flare was observed.<ref name=Valníček>{{cite journal |last1=Valníček |first1=B |last2=Peřestý |first2=R|last3=Zhitnik |first3=I |date=January–February 1991 |title=Results of the solar x-ray image study onboard the Phobos 1 space probe (the TEREK experiment) |url=https://www.sciencedirect.com/science/article/abs/pii/003206339190119U |journal=Planetary and Space Science |volume=39 |issue=1–2 |pages=7–11 |doi=10.1016/0032-0633(91)90119-U |bibcode=1991P&SS...39....7V |url-access=subscription }}</ref>

== Legacy ==
''Phobos 1'' failed before it could achieve its main scientific objectives, and while the Phobos program as a whole can be considered a failure, the probes discovered previously unknown information concerning Mars and Phobos during their lengthy orbital flights. In 1988, less was known about Mars and its satellites than the more distant [[gas giant]]s.<ref>{{Cite journal|last1=Zelenyi|first1=L M|last2=Zakharov|first2=A V|last3=Polishuk|first3=G M|last4=Martynov|first4=M B|date=February 2010|title=Project of the Mission to Phobos|journal= Solar System Research|volume=44|issue=1|page=15|doi=10.1134/S003809461001003X|bibcode=2010SoSyR..44...15Z|s2cid=120712230|id={{ProQuest|872828662}}}}</ref>

==See also==
{{Portal|Spaceflight}}
* [[List_of_software_bugs#Space|List of software bugs]]

== References ==
{{reflist}}

{{Mars spacecraft}}
{{Portal bar|Solar System}}

[[Category:Missions to Mars]]
[[Category:1988 in the Soviet Union]]
[[Category:Soviet Mars missions]]
[[Category:Derelict satellites in heliocentric orbit]]
[[Category:Non Earth orbiting satellites of the Soviet Union]]
[[Category:Phobos (moon)]]
[[Category:Spacecraft launched in 1988]]