It was launched on 8 November 2011, at 20:16UTC, from theBaikonur Cosmodrome, but subsequent rocket burns intended to set the craft on a course for Mars failed, leaving it stranded inlow Earth orbit.[6][7] Efforts to reactivate the craft were unsuccessful, and it fell back to Earth in an uncontrolledre-entry on 15 January 2012, over thePacific Ocean, west ofChile.[8][9][10] The return vehicle was to have returned to Earth in August 2014, carrying up to 200 g (7.1 oz) of soil from Phobos.
Funded by theRussian Federal Space Agency and developed byLavochkin and theRussian Space Research Institute, Fobos-Grunt was the first Russian-led interplanetary mission since the failedMars 96. The last successful interplanetary missions were the SovietVega 2 in 1985–1986, and the partially successfulPhobos 2 in 1988–1989.[11] Fobos-Grunt was designed to become the first spacecraft to return a macroscopic sample from an extraterrestrial body sinceLuna 24 in 1976.[12]
The cost of the project was 1.5 billion rubles (US$64.4 million).[citation needed] Project funding for the timeframe 2009–2012, including post-launch operations, was about 2.4 billion rubles.[13] The total cost of the mission was to have been 5 billion rubles (US$163 million).
According to lead scientistAlexander Zakharov, the entire spacecraft and most of the instruments were new, though the designs drew upon the nation's legacy of three successfulLuna missions, which in the 1970s retrieved a few hundred grams of Moon rocks.[14] Zakharov had described the Phobos sample return project as "possibly the most difficult interplanetary one to date".[15]
Image of Phobos. The Fobos-Grunt project began with the feasibility study of a Phobos sample-return mission in 1999.Mockup of the spacecraft's main propulsion unit
The Fobos-Grunt project began in 1999, when theRussian Space Research Institute andNPO Lavochkin, the main developer of Soviet and Russian interplanetary probes, initiated a 9 millionrouble feasibility study into a Phobos sample-return mission. The initial spacecraft design was to be similar to the probes of thePhobos program launched in the late 1980s.[16] Development of the spacecraft started in 2001 and the preliminary design was completed in 2004.[citation needed] For years, the project stalled as a result of low levels of financing of the Russian space program. This changed in the summer of 2005, when the new government plan for space activities in 2006–2015 was published. Fobos-Grunt was now made one of the program's flagship missions. With substantially improved funding, the launch date was set for October 2009. The 2004 design was revised a couple of times and international partners were invited to join the project.[16] In June 2006, NPO Lavochkin announced that it had begun manufacturing and testing the development version of the spacecraft's onboard equipment.[citation needed]
On 26 March 2007, Russia and China signed a cooperative agreement on the joint exploration of Mars, which included sending China's first interplanetary probe,Yinghuo-1, to Mars together with the Fobos-Grunt spacecraft.[citation needed] Yinghuo-1 weighed 115 kg (254 lb) and would have been released by the main spacecraft into a Mars orbit.[17]
NPO Lavochkin was the project's main contractor developing its components. The Chief Designer of Fobos-Grunt wasMaksim Martynov.[18] Phobos soil sampling and downloading were developed by the GEOHI RAN Institute of theRussian Academy of Sciences (Vernadski Institute of Geochemistry and Analytical chemistry) and the integrated scientific studies of Phobos and Mars by remote and contact methods were the responsibility of theRussian Space Research Institute,[19] whereAlexander Zakharov served as lead scientist of the mission.[15]
The ChineseYinghuo-1 orbiter was launched together with Fobos-Grunt.[20] In late 2012, after a 10–11.5-month cruise, Yinghuo-1 would have separated and entered an 800 × 80,000 km equatorial orbit (5° inclination) with a period of three days. The spacecraft was expected to remain on Martian orbit for one year. Yinghuo-1 would have focused mainly on the study of the external environment of Mars. Space center researchers expected to use photographs and data to study the magnetic field of Mars and the interaction betweenionospheres, escape particles andsolar wind.[21]
A second Chinese payload, the Soil Offloading and Preparation System (SOPSYS), was integrated in the lander. SOPSYS was a microgravity grinding tool developed by theHong Kong Polytechnic University.[22][23]
Another payload on Fobos-Grunt was an experiment from thePlanetary Society calledLiving Interplanetary Flight Experiment; its goal was to test whether selectedorganisms can survive a few years indeep space by flying them through interplanetary space. The experiment would have tested one aspect oftranspermia, the hypothesis that life could survive space travel, if protected inside rocks blasted by impact off one planet to land on another.[24][25][26][27]
TwoMetNet Mars landers developed by theFinnish Meteorological Institute, were planned to be included as payload of the Fobos-Grunt mission,[29][30] but weight constraints on the spacecraft required dropping the MetNet landers from the mission.[13]
The October 2009 launch date could not be achieved due to delays in the spacecraft development. During 2009, officials admitted that the schedule was very tight, but still hoped until the last moment that a launch could be made.[26] On 21 September 2009, the mission was officially announced to be delayed until the next launch window in 2011.[13][31][32][33] A main reason for the delay was difficulties encountered during development of the spacecraft's onboard computers. While the Moscow-based company Tehkhom provided the computer hardware on time, the internal NPO Lavochkin team responsible for integration and software development fell behind schedule.[34] The retirement of NPO Lavochkin's head Valeriy N. Poletskiy in January 2010 was widely seen as linked to the delay of Fobos-Grunt. Viktor Khartov was appointed the new head of the company. During the extra development time resulting from the delay, aPolish-built drill was added to the Phobos lander as a back-up soil extraction device.[35]
The spacecraft arrived atBaikonur Cosmodrome on 17 October 2011 and was transported to Site 31 for pre-launch processing.[36] The Zenit-2SB41 launch vehicle carrying Fobos-Grunt successfully lifted off from Baikonur Cosmodrome at 20:16UTC on 8 November 2011.[citation needed] The Zenit booster inserted the spacecraft into an initial 207 km × 347 km (129 mi × 216 mi) ellipticallow Earth orbit with an inclination of 51.4°.[37]
Two firings of the main propulsion unit in Earth orbit were required to send the spacecraft onto the interplanetary trajectory. Since both engine ignitions would have taken place outside the range of Russian ground stations, the project participants asked volunteers around the world to take optical observations of the burns, e.g. with telescopes, and report the results to enable more accurate prediction of the mission flight path upon entry into the range of Russian ground stations.[38]
It was expected that after 2.5 hours and 1.7 revolutions in the initial orbit, the autonomous main propulsion unit (MDU), derived from theFregat upper stage, would conduct its firing to insert the spacecraft into the elliptical orbit (250 km x 4150–4170 km) with a period of about 2.2 hours. After the completion of the first burn, the external fuel tank of the propulsion unit was expected to be jettisoned, with ignition for a second burn to depart Earth orbit scheduled for one orbit, or 2.1 hours, after the end of the first burn.[37][39][40] The propulsion module constitutes the cruise-stage bus of Fobos-Grunt. According to original plans, Mars orbit arrival had been expected during September 2012 and the return vehicle was scheduled to reach Earth in August 2014.[19][41]
Following what would have been the planned end of the first burn, the spacecraft could not be located in the target orbit. The spacecraft was subsequently discovered to still be in its initialparking orbit and it was determined that the burn had not taken place.[6] Initially, engineers had about three days from launch to rescue the spacecraft before its batteries ran out.[17] It was then established that the craft's solar panels had deployed, giving engineers more time to restore control. It was soon discovered the spacecraft was adjusting its orbit, changing its expected re-entry from late November or December 2011 to as late as early 2012.[42] Even though it had not been contacted, the spacecraft seemed to be actively adjusting itsperigee (the point it is closest to Earth in its orbit).[42][43]
On 22 November 2011, a signal from the probe was picked up by theEuropean Space Agency's tracking station in Perth,Australia, after it had sent the probe the command to turn on one of its transmitters. TheEuropean Space Operations Centre (ESOC) inDarmstadt,Germany, reported that the contact was made at 20:25 UTC on 22 November 2011 after some modifications had been made to the 15 metres (49 ft) dish facility inPerth to improve its chances of getting a signal.[44] Notelemetry was received in this communication.[45] It remained unclear whether the communications link would have been sufficient to command the spacecraft to switch on its engines to take it on its intended trajectory toward Mars.[46] Roscosmos officials said that the window of opportunity to salvage Fobos-Grunt would close in early December 2011.[46]
The next day, on 23 November 2011, the Perth station again made contact with the spacecraft and during 6 minutes, about 400 telemetry "frames" and Doppler information were received.[45][47][48] The amount of information received during this communication was not sufficient, and therefore it was not possible to identify the problem with the probe.[48][49] Further communication attempts made by ESA were unsuccessful and contact was not reestablished.[50] The space vehicle did not respond to the commands sent by theEuropean Space Agency to raise its orbit. Roscosmos provided these commands to ESA.[45]
From Baikonour,Kazakhstan, Roscosmos was able to receive telemetry from Fobos-Grunt on 24 November 2011[citation needed] but attempts to contact it failed. This telemetry demonstrated that the probe's radio equipment was working and that it was communicating with the spacecraft's flight control systems.[citation needed] Moreover, Roscosmos's top officials believed Fobos-Grunt to be functional, stably oriented and charging batteries through its solar panels.[45]
In a late November 2011 interview, the service manager of the European Space Agency for Fobos-Grunt, Wolfgang Hell, stated that Roscosmos had a better understanding of the problem with the spacecraft, saying they reached the conclusion that they have some kind of power problem on board.[51]
ESA failed to communicate with the space probe in all of the five opportunities the agency had between 28 and 29 November 2011. During those occasions, the spacecraft did not comply with orders to fire the engines and raise its orbit. The Russian space agency then requested that ESA repeat the orders.[52] The European Space Agency decided to end the efforts to contact the probe on 2 December 2011, with one analyst saying that Fobos-Grunt appeared "dead in the water".[53] However, ESA made teams available to assist the Fobos-Grunt mission if there was a change in situation.[49] In spite of that, Roscosmos stated its intention to continue to try to contact the space vehicle until it entered the atmosphere.[citation needed]
TheU.S. Strategic Command'sJoint Space Operations Center (JSpOC) tracked the probe and identified at the start of December 2011 that Fobos-Grunt had an elliptical Earth orbit at an altitude of between 209 km (130 mi) and 305 km (190 mi), but falling a few kilometers each day.[54][55]
Before reentry, the spacecraft still carried about 7.51 tonnes of highly toxichydrazine andnitrogen tetroxide on board.[7][17] This was mostly fuel for the spacecraft's upper stage. These compounds, with melting points of 2 °C and −11.2 °C, are normally kept in liquid form and were expected to burn out during re-entry.[17] NASA veteranJames Oberg said the hydrazine and nitrogen tetroxide "could freeze before ultimately entering", thus contaminating the impact area.[7] He also stated that if Fobos-Grunt were not salvaged, it may be the most dangerous object to fall from orbit.[7] Meanwhile, the head of Roscosmos said the probability of parts reaching the Earth surface was "highly unlikely" and that the spacecraft, including the LIFE module and the Yinghuo-1 orbiter, would be destroyed during re-entry.[17]
Russian military sources claimed that Fobos-Grunt was somewhere over the Pacific Ocean between New Zealand and South America when it re-entered the atmosphere at about 17:45 UTC.[citation needed] Although it was initially feared its remains would reach land as close as 145 kilometres (90 mi) west ofSanta Fe, Argentina, the Russian military Air and Space Defense Forces reported that it ultimately fell into the Pacific Ocean, 1,247 km (775 mi) west ofWellington Island, Chile.[9] The Defence Ministry spokesman subsequently revealed that such estimate was based on calculations, without witness reports. In contrast, Russian civilian ballistic experts said that the fragments had fallen over a broader patch of Earth's surface, and that the midpoint of the crash zone was located in theGoiás state ofBrazil.[56][57]
Initially, the head of RoscosmosVladimir Popovkin, suggested that the Fobos-Grunt failure might have been the result of sabotage by a foreign nation.[58][59] He also stated that risky technical decisions had been made because of limited funding. On 17 January 2012, an unidentified Russian official speculated that a U.S. radar stationed on theMarshall Islands may have inadvertently disabled the probe, but cited no evidence.[60] Popovkin suggested the microchips may have been counterfeit,[61][62] then he announced on 1 February 2012 that a burst ofcosmic radiation may have caused computers to reboot and go into a standby mode.[63][64] Industry experts cast doubt on the claim citing how unlikely the effects of such a burst are in low Earth orbit, inside the protection ofEarth's magnetic field.[65]
On 6 February 2012, the commission investigating the mishap concluded that Fobos-Grunt mission failed because of "a programming error which led to a simultaneous reboot of two working channels of an onboard computer". The craft's rocket pack never fired due to the computer reboot, leaving the craft stranded in Earth orbit.[66][67] Although the specific failure was identified, experts suggest it was the culmination of poor quality control,[68][69] lack of testing,[70] security issues and corruption.[71] Russian presidentDmitry Medvedev suggested that those responsible should be punished and perhaps criminally prosecuted.[61][72][73]
In January 2012, scientists and engineers at theRussian Space Research Institute andNPO Lavochkin called for a repeat sample return mission calledFobos-Grunt-2[74] andBoomerang[75][76] for launch in 2020.[77][78] Popovkin declared that they would soon attempt to repeat the Fobos-Grunt mission, if an agreement was not reached for Russian co-operation in theEuropean Space Agency'sExoMars program.[citation needed] However, since an agreement was reached for the inclusion of Russia as a full project partner,[79] some instruments originally developed for Fobos-Grunt were flown in theExoMars Trace Gas Orbiter.[80]
On 2 August 2014, theRussian Academy of Sciences stated that the Phobos-Grunt repeat mission might be restarted for a launch approximately in 2024.[81][82] In August 2015, theESA-Roscosmos working group on post-ExoMars cooperation, completed a joint study for a possible future Phobos sample return mission, preliminary discussions were held,[83][84] and in May 2015 the Russian Academy of Sciences submitted a budget proposal.[83][85]
As of September 2023, Roscosmos intended to launch Boomerang "after 2030".[86]
Boomerang is intended to be the first stage of the RussianMars sample return mission calledMars-Grunt.[85][87][88] This Mars sample-return mission would be developed from the technologies demonstrated by Fobos-Grunt-2.[85]
Fobos-Grunt was an intended interplanetary probe that included a lander to study Phobos and a sample return vehicle to return a sample of about 200 g (7.1 oz) of soil toEarth.[1] It was also to study Mars from orbit, including itsatmosphere and dust storms, plasma and radiation.
Science goals
Delivery of samples of Phobos soil to Earth for scientific research of Phobos, Mars and Martian vicinity;
In situ and remote studies of Phobos (to include analysis of soil samples);
Monitoring the atmospheric behavior of Mars, including the dynamics of dust storms;
Studies of the vicinity of Mars, including its radiation environment,plasma and dust;[19]
Study of the origin of the Martian moons and their relation to Mars;
Study of the role played by asteroid impacts in the formation of terrestrial planets;
Modules -- A: lander, B: return module, C: reentry vehicle (not shown).Major components -- 1: solar panels, 2: reaction wheels, 3: landing gear, 4: robotic sample arm (second arm not shown), 6: sample transfer container, 7: attitude control thrusters, 8 and 10: fuel and helium tanks, 9: return module solar panels.Scientific instruments (some instruments are not visible from this angle or are not present on the model) -- a: TERMOFOB thermodetector, b: GRAS-F seismogravimeter; c: Meteor-F cosmic dust detector, d: GAP (Gas Analytic Package) pyrolizer/thermal-differential analyzer, e: GAP gas chromatograph; f: GAP mass spectrometer, g: LAZMA mass spectrometer, h: MANAGA-F mass spectrometer, i: FPMS plasma complex
The spacecraft's journey to Mars would take about ten months. After arriving in Mars orbit, the main propulsion unit and the transfer truss would separate and the Chinese Mars orbiter would be released. Fobos-Grunt would then spend several months studying the planet and its moons from orbit, before landing onPhobos. It was imperative to prevent the introduction to Mars of contaminants from Earth; according to Fobos-Grunt Chief DesignerMaksim Martynov, the probability of the probe accidentally reaching the surface of Mars was much lower than the maximum specified for Category III missions, the type assigned to Fobos-Grunt and defined inCOSPAR'splanetary protection policy (in accordance withArticle IX of the Outer Space Treaty).[103][104]
Phobos-Grunt aroundMars: (1) Arrival of Phobos-Grunt, (2) Insertion maneuver in orbit around Mars, (3) Drop of theFregat stage and separation of the probe and Yinghuo-1, (4) Maneuver for to raise theperiapsis, (5) Yinghuo 1 starts his mission on the first orbit, (6) Maneuver to place himself in an orbit close to that of Phobos; (A) Orbit of Phobos, (B) Orbit of insertion of Phobos-Grunt andYinghuo-1, (C) Orbit with raised periapsis, (D)Quasi-synchronous orbit with Phobos.
The planned landing site at Phobos was a region from 5°S to 5°N, 230° to 235°E.[105] Soil sample collection would begin immediately after the lander touched down on Phobos, with collection lasting 2–7 days. An emergency mode existed for the case of communications breakdown, which enabled the lander to automatically launch the return rocket to deliver the samples to Earth.[26]
A robotic arm would have collected samples up to 1.3 cm (0.51 in) in diameter. At the end of the arm was a pipe-shaped tool which split to form a claw. The tool contained a piston which would have pushed the sample into a cylindrical container. A light-sensitive photo-diode would have confirmed whether material collection was successful and also allowed visual inspection of the digging area. The sample extraction device would have performed 15 to 20 scoops yielding a total of 85 to 156 g (3.0 to 5.5 oz) of soil.[26] The samples would be loaded into a capsule which would then be moved inside a special pipeline into the descent module by inflating an elastic bag within the pipe with gas.[103] Because the characteristics of Phobos soil are uncertain, the lander included another soil-extraction device, a Polish-built drill, which would have been used in case the soil turned out to be too rocky for the main scooping device.[12][35]
After the departure of the return stage, the lander's experiments would have continuedin situ on Phobos's surface for a year. To conserve power, mission control would have turned these on and off in a precise sequence. The robotic arm would have placed more samples in a chamber that would heat it and analyze itsemission spectra. This analysis might have been able to determine the presence of volatile compounds, such as water.[26]
The return stage was mounted on top of the lander. It would have needed to accelerate to 35 km/h (22 mph) to escape Phobos's gravity. In order to avoid harming the experiments remaining at the lander, the return stage would have ignited its engine once the vehicle had been vaulted to a safe height by springs. It would then have begun maneuvers for the eventual trip to Earth, where it would have arrived in August 2014.[26] An 11-kg descent vehicle containing the capsule with soil samples (up to 0.2 kg (0.44 lb)) would have been released on direct approach to Earth at 12 km/s (7.5 mi/s).[96] Following the aerodynamic braking to 30 m/s (98 ft/s) the conical descent vehicle would perform a hard landing without a parachute within theSary Shagan test range inKazakhstan.[103][106] The vehicle did not have any radio equipment.[12] Ground-based radar and optical observations would have been used to track the vehicle's return.[107]
Three course corrections of up to 130 m/sdelta V foreseen during Earth-Mars cruise
Mars arrival
25 August – 26 September 2012
945 m/s braking burn to enter initial Mars parting orbit withperiapsis = 800 ± 400 km,apoapsis = 79,000 km and period of three days. Propulsion module and Yinghuo-1 separates from the rest of the craft.
Transfer to intermediate Mars orbit
October – December 2012
220 m/s engine burn to raise periapsis to 6499 km, changing the orbital period to 3.3 days and theorbital inclination to that of Phobos.
Transfer to Phobos observation orbit
December 2012
705 m/s engine burn to insert the craft into an early circular orbit with an average radius of 9910 km, i.e. about 535 km above Phobos orbit, and orbital period = 8.3 h.
Rendezvous with Phobos
January 2013
45 m/s + 20 m/s engine burns for transfer to quasi-synchronous orbit where the probe always remains within 50..140 km of Phobos.
Phobos landing and surface activities
End of January – beginning of April 2013
Landing maneuver takes two hours (100 m/s delta V trajectory changes).
Separation of Earth return vehicle (ERV) from lander
April 2013
10 m/s + 20 m/s trajectory change to enter parking orbit 300–350 km lower than Phobos with a period of 7.23 hours.
ERV transfer orbit
Starting in August 2013
740 m/s periapsis burn for insertion into 3-day elliptical transfer orbit.
ERV pre orbit insertion
Mid-August 2013
125 m/s burn to change the inclination of the orbit while decreasing the periapsis distance to 500–1000 km above the martian surface.
ERV trans-Earth injection burn
3–23 September 2013
Final 790 m/s engine burn to accelerate out of Mars orbit.
ERV Earth arrival
15–18 August 2014
Up to five trajectory corrections (combined delta V < 130 m/s) would be performed before atmospheric entry.
Barry E. DiGregorio, Director of theInternational Committee Against Mars Sample Return (ICAMSR), criticised theLIFE experiment carried by Fobos-Grunt as a violation of theOuter Space Treaty due to the possibility of contamination of Phobos or Mars with the microbial spores and live bacteria it contains should it have lost control and crash-landed on either body.[111] It is speculated that the heat-resistant extremophile bacteria could survive such a crash, on the basis thatMicrobispora bacteria survived theSpace Shuttle Columbia disaster.[112]
According to Fobos-Grunt Chief DesignerMaksim Martynov, the probability of the probe accidentally reaching the surface of Mars was much lower than the maximum specified for Category III missions, the type assigned to Fobos-Grunt and defined inCOSPAR'splanetary protection policy (in accordance withArticle IX of the Outer Space Treaty).[103][104]
^Sanderson, Katharine (18 January 2012)."Phobos-Grunt Crashes into the Pacific".Astrobiology Magazine. Archived from the original on 25 September 2020. Retrieved28 March 2012.
^ab"Phobos-Grunt chips supposedly were counterfeit". Voronezh: ITAR-TASS. 31 January 2012. Retrieved8 November 2025.heavy charged particles of space, which caused malfunction of the memory system during the second circuit in the orbit ... may have been counterfeit
^Dwayne A. Day (28 November 2011)."Red Planet blues". The Space Review. Retrieved18 April 2012.
^Korablev, O (23 September 2003).Russian programme for deep space exploration(PDF). IAA-ESA Workshop, The Next Steps in Exploring Deep Space. ESTEC, Noordwijk, The Netherlands: Space Research Institute (IKI). p. 14. Archived fromthe original(PDF) on 29 November 2011. Retrieved3 August 2008.
^Rodionov, D. S.; Klingelhoefer, G.; Evlanov, E. N.; Blumers, M.; Bernhardt, B.; Gironés, J.; Maul, J.; Fleischer, I.; Prilutskii, O. F.; Shlyk, A. F.; Linkin, V. M.; d'Uston, C. (2010). "The miniaturized Möessbauer spectrometer MIMOS II for the Phobos-Grunt mission".Solar System Research.44 (5):362–370.Bibcode:2010SoSyR..44..362R.doi:10.1134/S0038094610050023.
^Rickman, H.; Słaby, E.; Gurgurewicz, J.; Śmigielski, M.; Banaszkiewicz, M.; Grygorczuk, J.; Morawski, M.; Seweryn, K.; Wawrzaszek, R. (2014). "CHOMIK: A multi-method approach for studying Phobos".Solar System Research.48 (4):279–286.Bibcode:2014SoSyR..48..279R.doi:10.1134/S0038094614040091.
^Pilorget, C.; Bibring, J. -P.; Berthe, M. (2011). "MicrOmega: An IR Hyperspectral Microscope for the Phobos Grunt Lander".42nd Annual Lunar and Planetary Science Conference (1608): 1930.Bibcode:2011LPI....42.1930P.
^Korablev, O. I.; Grigoriev, A. V.; Moshkin, B. E.; Patsaev, D. V.; Makarov, V. S.; Maksimenko, S. V.; Grechnev, K. V.; Kotlov, V. I.; Zasova, L. V.; Shakun, A. V.; Fedorova, A. A.; Terentiev, A. I.; Ekonomov, A. P.; Khatuntsev, I. V.; Mayorov, B. S.; Nikolsky, Yu. V.; Maslov, I. A.; Gvozdev, A. B.; Montmessin, F.; Kuzmin, R. O. (2009). "The AOST miniature Fourier spectrometer for space studies".Journal of Optical Technology.76 (5): 316.doi:10.1364/JOT.76.000316.
^Korablev, Oleg; Montmessin, Franck; Trokhimovsky, Alexander; Fedorova, Anna A.; Kiselev, Alexander V.; Bertaux, Jean-Loup; Goultail, Jean-Pierre; Belyaev, Denis A.; Stepanov, Alexander V.; Titov, Andrei Yu.; Kalinnikov, Yurii K. (2013). "Compact echelle spectrometer for occultation sounding of the Martian atmosphere: Design and performance".Applied Optics.52 (5):1054–1065.Bibcode:2013ApOpt..52.1054K.doi:10.1364/AO.52.001054.PMID23400068.
^"Optical Solar Sensor". Space Research Institute of the Russian Academy of Sciences. Archived fromthe original on 19 July 2011. Retrieved20 July 2009.
^Wieser, M.; Barabash, S. (2016). "A family for miniature, easily reconfigurable particle sensors for space plasma measurements".Journal of Geophysical Research: Space Physics.121 (12).Bibcode:2016JGRA..12111588W.doi:10.1002/2016JA022799.
M. Ya. Marov, V. S. Avduevsky, E. L. Akim, T. M. Eneev, R. S. Kremnev, S. D. Kulikov, K. M. Pichkhadze, G. A. Popov, G. N. Rogovsky; Avduevsky; Akim; Eneev; Kremnev; Kulikov; Pichkhadze; Popov; Rogovsky (2004). "Phobos-Grunt: Russian sample return mission".Advances in Space Research.33 (12):2276–2280.Bibcode:2004AdSpR..33.2276M.doi:10.1016/S0273-1177(03)00515-5.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Rodionov, D. S.; Klingelhoefer, G.; Evlanov, E. N.; Blumers, M.; Bernhardt, B.; Gironés, J.; Maul, J.; Fleischer, I.; et al. (2010). "The miniaturized Möessbauer spectrometer MIMOS II for the Phobos-Grunt mission".Solar System Research.44 (5): 362.Bibcode:2010SoSyR..44..362R.doi:10.1134/S0038094610050023.S2CID122144645.
Missions are ordered by launch date. Sign† indicates failure en route or before intended mission data returned.‡ indicates use of the planet as agravity assist en route to another destination.
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).