# Viking program

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Pair of NASA landers and orbiters sent to Mars in 1976

This article is about the NASA Mars probes. For the Swedish spacecraft, see [Viking (satellite)](/source/Viking_(satellite)).

"Viking Mars" redirects here. For the cruise ship, see [Viking Cruises](/source/Viking_Cruises).

Viking Artist impression of a Viking orbiter releasing a lander descent capsule Manufacturer Jet Propulsion Laboratory / Martin Marietta Country of origin United States Operator NASA / JPL Applications Mars orbiter/lander Specifications Launch mass 3,527 kilograms (7,776 lb) Power Orbiters: 620 watts (solar array) Lander: 70 watts (two RTG units) Regime Areocentric Design life Orbiters: 4 years at Mars Landers: 4–6 years at Mars Production Status Retired Built 2 Launched 2 Retired Viking 1 orbiter August 17, 1980[1] Viking 1 lander July 20, 1976[1] (landing) to November 13, 1982[1] Viking 2 orbiter July 25, 1978[1] Viking 2 lander September 3, 1976[1] (landing) to April 11, 1980[1] Maiden launch Viking 1 August 20, 1975[1][2] Last launch Viking 2 September 9, 1975[1][3]

The ***Viking* program** consisted of a pair of identical American [space probes](/source/Space_probe), *[Viking 1](/source/Viking_1)* and *[Viking 2](/source/Viking_2)* both launched in 1975, and landed on [Mars](/source/Mars) in 1976.[1] The mission effort began in 1968 and was managed by the NASA Langley Research Center.[4] Each [spacecraft](/source/Spacecraft) was composed of two main parts: an [orbiter](/source/Orbiter) spacecraft which photographed the surface of Mars from [orbit](/source/Orbit), and a [lander](/source/Lander_(spacecraft)) which studied the planet from the surface. The orbiters also served as communication relays for the landers once they touched down.

The Viking program grew from [NASA](/source/NASA)'s earlier, even more ambitious, [Voyager Mars](/source/Voyager_program_(Mars)) program, which was not related to the successful [Voyager deep space probes](/source/Voyager_program) of the late 1970s. *Viking 1* was launched on August 20, 1975, and the second craft, *Viking 2*, was launched on September 9, 1975, both riding atop [Titan IIIE](/source/Titan_IIIE) rockets with [Centaur](/source/Centaur_(rocket_stage)) upper stages. *Viking 1* entered Mars orbit on June 19, 1976, with *Viking 2* following on August 7.

After orbiting Mars for more than a month and returning images used for landing site selection, the orbiters and landers detached; the landers then entered the Martian [atmosphere](/source/Atmosphere) and [soft-landed](/source/Soft_landing_(rocketry)) at the sites that had been chosen. The *Viking 1* lander touched down on the surface of Mars on July 20, 1976, more than two weeks before *Viking 2*'s arrival in orbit. *Viking 2* then successfully soft-landed on September 3. The orbiters continued imaging and performing other scientific operations from orbit while the landers deployed [instruments](/source/Measuring_instrument) on the surface. The program terminated in 1982.

The project cost was roughly US$1 billion at the time of launch,[5][6] equivalent to about $6 billion in 2024 dollars.[7] The mission was considered successful and formed most of the body of knowledge about Mars through the late 1990s and early 2000s.[8][9]

## Science objectives

- Obtain high-resolution images of the Martian surface

- Characterize the structure and composition of the atmosphere and surface

- Search for evidence of [life on Mars](/source/Life_on_Mars_(planet))

## Viking orbiters

The primary objectives of the two Viking orbiters were to transport the landers to Mars, perform reconnaissance to locate and certify landing sites, act as communications relays for the landers, and to perform their own scientific investigations. Each orbiter, based on the earlier [Mariner 9](/source/Mariner_9) spacecraft, was an [octagon](/source/Octagon) approximately 2.5 m (8.2 ft) across. The fully fueled orbiter-lander pair had a [mass](/source/Mass) of 3,527 kg (7,776 lb). After separation and landing, the lander had a mass of about 600 kg (1,300 lb) and the orbiter 900 kg (2,000 lb). The total launch mass was 2,328 kg (5,132 lb), of which 1,445 kg (3,186 lb) were propellant and [attitude control](/source/Spacecraft_attitude_control) gas. The eight faces of the ring-like structure were 0.457 m (18 in) high and were alternately 1.397 and 0.508 m (55 and 20 in) wide. The overall height was 3.29 m (10.8 ft) from the lander attachment points on the bottom to the launch vehicle attachment points on top. There were 16 modular compartments, 3 on each of the 4 long faces and one on each short face. Four solar panel wings extended from the [axis](/source/Coordinate_axis) of the orbiter, the distance from tip to tip of two oppositely extended solar panels was 9.75 m (32 ft).

### Propulsion

The main [propulsion](/source/Spacecraft_propulsion) unit was mounted above the [orbiter bus](/source/Satellite_bus). Propulsion was furnished by a [bipropellant](/source/Bipropellant) ([monomethylhydrazine](/source/Monomethylhydrazine) and [nitrogen tetroxide](/source/Nitrogen_tetroxide)) liquid-fueled [rocket engine](/source/Rocket_engine) which could be [gimballed](/source/Gimbal) up to 9 [degrees](/source/Degree_(angle)). The engine was capable of 1,323 [N](/source/Newton_(unit)) (297 [lbf](/source/Pound_(force))) thrust, providing a [change in velocity](/source/Delta-V) of 1,480 m/s (3,300 mph). [Attitude control](/source/Spacecraft_attitude_control) was achieved by 12 small compressed-nitrogen jets.

### Navigation and communication

An acquisition [Sun sensor](/source/Sun_sensor), a cruise Sun sensor, a [Canopus](/source/Canopus) [star tracker](/source/Star_tracker) and an inertial reference unit consisting of six [gyroscopes](/source/Gyroscope) allowed three-axis stabilization. Two [accelerometers](/source/Accelerometers) were also on board.

Communications were accomplished through a 20 W [S-band](/source/S-band) (2.3 [GHz](/source/Gigahertz)) [transmitter](/source/Transmitter) and two 20 W [TWTAs](/source/TWTA). An [X band](/source/X-band) (8.4 GHz) [downlink](/source/Downlink) was also added specifically for [radio science](/source/Doppler_effect) and to conduct communications experiments. [Uplink](/source/Uplink) was via S band (2.1 GHz). A two-axis steerable [parabolic dish antenna](/source/Directional_antenna) with a diameter of approximately 1.5 m was attached at one edge of the orbiter base, and a fixed low-gain antenna extended from the top of the bus. Two tape recorders were each capable of storing 1280 [megabits](/source/Megabit). A 381-[MHz](/source/MHz) relay radio was also available.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

### Power

The power to the two orbiter craft was provided by eight 1.57 m × 1.23 m (62 in × 48 in) [solar panels](/source/Solar_panels), two on each wing. The solar panels comprised a total of 34,800 solar cells and produced 620 W of power at Mars. Power was also stored in two [nickel-cadmium](/source/Nickel-cadmium) 30-[A·h](/source/Ampere_hour) [batteries](/source/Battery_(electricity)).

The combined area of the four panels was 15 square meters (160 square feet), and they provided both regulated and unregulated direct current power; unregulated power was provided to the radio transmitter and the lander.

Two 30-amp·hour, nickel-cadmium, rechargeable batteries provided power when the spacecraft was not facing the Sun, during launch, while performing correction maneuvers and also during Mars occultation.[10]

### Main findings

Mars image mosaic from the *Viking 1* orbiter

By discovering many geological forms that are typically formed from large amounts of water, the images from the orbiters caused a revolution in our ideas about [water on Mars](/source/Water_on_Mars). Huge river valleys were found in many areas. They showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and travelled thousands of kilometers. Large areas in the southern hemisphere contained branched stream networks, suggesting that rain once fell. The flanks of some volcanoes are believed to have been exposed to rainfall because they resemble those caused on Hawaiian volcanoes. Many craters look as if the impactor fell into mud. When they were formed, ice in the soil may have melted, turned the ground into mud, then flowed across the surface. Normally, material from an impact goes up, then down. It does not flow across the surface, going around obstacles, as it does on some Martian craters.[11][12][13] Regions, called "[Chaotic Terrain](/source/Martian_chaos_terrain)," seemed to have quickly lost great volumes of water, causing large channels to be formed. The amount of water involved was estimated to ten thousand times the flow of the [Mississippi River](/source/Mississippi_River).[14] Underground volcanism may have melted frozen ice; the water then flowed away and the ground collapsed to leave chaotic terrain.

**Viking mosaics**

		- Streamlined islands show that large floods occurred on Mars. (*[Lunae Palus quadrangle](/source/Lunae_Palus_quadrangle)*)

		- Scour patterns were produced by flowing water. [Dromore](/source/Dromore_(crater)) crater is at bottom. (*[Lunae Palus quadrangle](/source/Lunae_Palus_quadrangle)*)

		- Large floods of water likely eroded the channels around [Dromore](/source/Dromore_(crater)) crater. (*[Lunae Palus quadrangle](/source/Lunae_Palus_quadrangle)*)

		- Tear-drop shaped islands carved by flood waters from [Ares Vallis](/source/Ares_Vallis). (*[Oxia Palus quadrangle](/source/Oxia_Palus_quadrangle)*)

		- Image of three valleys: [Vedra Valles](/source/Vedra_Valles), [Maumee Valles](/source/Maumee_Valles), and [Maja Valles](/source/Maja_Valles). (*[Lunae Palus quadrangle](/source/Lunae_Palus_quadrangle)*)

		- [Arandas](/source/Arandas_(crater)) crater may be on top of large quantities of water ice, which melted when the impact occurred, producing a mud-like ejecta. (*[Mare Acidalium quadrangle](/source/Mare_Acidalium_quadrangle)*)

		- Channels running through [Alba Mons](/source/Alba_Mons). (*[Arcadia quadrangle](/source/Arcadia_quadrangle)*)

		- Branched channels in [Thaumasia quadrangle](/source/Thaumasia_quadrangle) provide possible evidence of past rain on Mars.

		- These branched channels provide possible evidence of past rain on Mars. (*[Margaritifer Sinus quadrangle](/source/Margaritifer_Sinus_quadrangle)*)

		- [Ravi Vallis](/source/Ravi_Vallis) was possibly formed from extreme flooding. (*[Margaritifer Sinus quadrangle](/source/Margaritifer_Sinus_quadrangle)*)

## Viking landers

Proof test article of the Viking lander

Astronomer [Carl Sagan](/source/Carl_Sagan) stands next to a model of a *Viking* lander to provide scale

Each lander comprised a six-sided aluminium base with alternate 1.09 and 0.56 m (43 and 22 in) long sides, supported on three extended legs attached to the shorter sides. The leg footpads formed the vertices of an equilateral triangle with 2.21 m (7.3 ft) sides when viewed from above, with the long sides of the base forming a straight line with the two adjoining footpads. Instrumentation was attached inside and on top of the base, elevated above the surface by the extended legs.[15]

Each lander was enclosed in an [aeroshell](/source/Aeroshell) heat shield designed to slow the lander down during the entry phase. To prevent contamination of Mars by Earth organisms, each lander, upon assembly and enclosure within the aeroshell, was enclosed in a pressurized "bioshield" and then [sterilized](/source/Sterilization_(microbiology)) at a temperature of 111 °C (232 °F) for 40 hours. For thermal reasons, the cap of the bioshield was jettisoned after the Centaur upper stage powered the Viking orbiter/lander combination out of Earth orbit.[16]

Astronomer [Carl Sagan](/source/Carl_Sagan) helped to choose landing sites for both *Viking* probes.[17]

### Entry, Descent and Landing (EDL)

Each lander arrived at Mars attached to the orbiter. The assembly orbited Mars many times before the lander was released and separated from the orbiter for descent to the surface. Descent comprised four distinct phases, starting with a [deorbit burn](/source/Deorbit#Deorbit_and_re-entry). The lander then experienced [atmospheric entry](/source/Atmospheric_entry) with peak heating occurring a few seconds after the start of frictional heating with the Martian atmosphere. At an altitude of about 6 kilometers (3.7 miles) and traveling at a velocity of 900 kilometers per hour (600 mph), the parachute deployed, the aeroshell released and the lander's legs unfolded. At an altitude of about 1.5 kilometers (5,000 feet), the lander activated its three retro-engines and was released from the parachute. The lander then immediately used [retrorockets](/source/Retrorockets) to slow and control its descent, with a [soft landing](/source/Soft_landing_(rocketry)) on the surface of Mars.[18]

First "clear" image ever transmitted from the surface of Mars – shows [rocks](/source/List_of_rocks_on_Mars#Viking) near the *[Viking 1](/source/Viking_1)* lander (July 20, 1976).

At landing (after using rocket propellant) the landers had a mass of about 600 kg.

### Propulsion

Propulsion for deorbit was provided by the [monopropellant](/source/Monopropellant) [hydrazine](/source/Hydrazine) (N2H4), through a rocket with 12 [nozzles](/source/Rocket_engine_nozzles) arranged in four clusters of three that provided 32 [newtons](/source/Newton_(unit)) (7.2 lbf) thrust, translating to a [change in velocity](/source/Delta-V) of 180 m/s (590 ft/s). These nozzles also acted as the control [thrusters](/source/Spacecraft_propulsion) for [translation](/source/Translation_(geometry)) and [rotation](/source/Rotation) of the lander.

Terminal [descent](/source/Descent_(aircraft)) (after use of a [parachute](/source/Parachute)) and [landing](/source/Landing) used three (one affixed on each long side of the base, separated by 120 degrees) monopropellant hydrazine engines. The engines had 18 [nozzles](https://artsandculture.google.com/asset/_/fgFN2s2GG-OfQA) to disperse the exhaust and minimize effects on the ground, and were [throttleable](/source/Throttle) from 276 to 2,667 [newtons](/source/Newton_(unit)) (62 to 600 lbf). The hydrazine was purified in order to prevent contamination of the Martian surface with Earth [microbes](/source/Microbes). The lander carried 85 kg (187 lb) of propellant at launch, contained in two spherical [titanium](/source/Titanium) tanks mounted on opposite sides of the lander beneath the RTG windscreens, giving a total launch mass of 657 kg (1,448 lb). Control was achieved through the use of an [inertial reference unit](/source/Inertial_reference_unit), four [gyros](/source/Gyroscope), a [radar altimeter](/source/Radar_altimeter), a terminal descent and landing [radar](/source/Radar), and the control thrusters.

### Power

Power was provided by two [radioisotope thermoelectric generator](/source/Radioisotope_thermoelectric_generator) (RTG) units containing [plutonium-238](/source/Plutonium-238) affixed to opposite sides of the lander base and covered by wind screens. Each Viking RTG[19] was 28 cm (11 in) tall, 58 cm (23 in) in diameter, had a mass of 13.6 kg (30 lb) and provided 30 watts of continuous power at 4.4 volts. Four [wet cell](/source/Wet_cell) sealed nickel-cadmium 8 [Ah](/source/Ampere_hours) (28,800 [coulombs](/source/Coulomb)), 28 volt [rechargeable batteries](/source/Rechargeable_battery) were also on board to handle peak power loads.

### Payload

Image from Mars taken by the *Viking 2* lander

#### Communications

Communications were accomplished through a 20-watt S-band transmitter using two [traveling-wave tubes](/source/Traveling-wave_tube). A two-axis steerable high-gain parabolic antenna was mounted on a boom near one edge of the lander base. An [omnidirectional](/source/Omnidirectional_antenna) low-gain S-band antenna also extended from the base. Both these antennae allowed for communication directly with the Earth, permitting Viking 1 to continue to work long after both orbiters had failed. A [UHF](/source/UHF) (381 MHz) antenna provided a one-way relay to the orbiter using a 30 watt relay radio. Data storage was on a 40-Mbit tape recorder, and the lander computer had a 6000-[word](/source/Word_(data_type)) memory for command instructions.

#### Instruments

The lander carried instruments to achieve the primary scientific objectives of the lander mission: to study the [biology](/source/Biology), chemical composition ([organic](/source/Organic_compound) and [inorganic](/source/Inorganic)), [meteorology](/source/Meteorology), [seismology](/source/Seismology), [magnetic](/source/Magnetism) properties, appearance, and physical properties of the Martian surface and atmosphere. Two 360-degree cylindrical scan cameras were mounted near one long side of the base. From the center of this side extended the sampler arm, with a collector head, [temperature sensor](/source/Sensor#Thermal), and [magnet](/source/Magnet) on the end. A [meteorology](/source/Climate_of_Mars) boom, holding temperature, wind direction, and wind velocity sensors extended out and up from the top of one of the lander legs. A [seismometer](/source/Seismometer), magnet and camera [test targets](/source/Test_target), and magnifying [mirror](/source/Mirror) are mounted opposite the cameras, near the high-gain antenna. An interior environmentally controlled compartment held the [biology](/source/Biology) experiment and the [gas chromatograph](/source/Gas_chromatography) mass spectrometer. The [X-ray](/source/X-ray) [fluorescence](/source/Fluorescence) spectrometer was also mounted within the structure. A [pressure](/source/Pressure) sensor was attached under the lander body. The scientific [payload](/source/Payload_(air_and_space_craft)) had a total mass of approximately 91 kg (201 lb).

### Biological experiments

Main article: [Viking biological experiments](/source/Viking_biological_experiments)

The Viking landers conducted [biological experiments](/source/Viking_biological_experiments) designed to detect [life in the Martian soil](/source/Life_on_Mars_(planet)) (if it existed) with experiments designed by three separate teams, under the direction of chief scientist [Gerald Soffen](/source/Gerald_Soffen) of NASA. One experiment turned positive for the detection of [metabolism](/source/Metabolism) (current life), but based on the results of the other two experiments that failed to reveal any [organic molecules](/source/Organic_matter) in the soil, most scientists became convinced that the positive results were likely caused by non-biological chemical reactions from highly oxidizing soil conditions.[20]

Dust dunes and a large boulder taken by the *Viking 1* lander.

Trenches dug by the soil sampler of the  *Viking 1* lander.

Although there was a pronouncement by NASA during the mission saying that the Viking lander results did not demonstrate conclusive [biosignatures](/source/Biosignature) in soils at the two landing sites, the test results and their limitations are still under assessment. The validity of the positive 'Labeled Release' (LR) results hinged entirely on the absence of an oxidative agent in the Martian soil, but one was later discovered by the [*Phoenix* lander](/source/Phoenix_lander) in the form of [perchlorate](/source/Perchlorate) salts.[21][22] It has been proposed that organic compounds could have been present in the soil analyzed by both *Viking 1* and *Viking 2*, but remained unnoticed due to the presence of perchlorate, as detected by Phoenix in 2008.[23] Researchers found that perchlorate will destroy organics when heated and will produce [chloromethane](/source/Chloromethane) and [dichloromethane](/source/Dichloromethane), the identical chlorine compounds discovered by both Viking landers when they performed the same tests on Mars.[24]

The question of microbial life on Mars remains unresolved. Nonetheless, on April 12, 2012, an international team of scientists reported studies, based on mathematical speculation through [complexity analysis](/source/Complexity_analysis) of the [Labeled Release experiments](/source/Viking_biological_experiments#Labeled_release) of the 1976 Viking Mission, that may suggest the detection of "extant microbial life on Mars."[25][26] In addition, new findings from re-examination of the Gas Chromatograph Mass Spectrometer (GCMS) results were published in 2018.[27]

### Camera/imaging system

Viking Lander Camera

The leader of the imaging team was [Thomas A. Mutch](/source/Thomas_A._Mutch), a geologist at [Brown University](/source/Brown_University) in [Providence, Rhode Island](/source/Providence%2C_Rhode_Island). The camera uses a movable mirror to illuminate 12 [photodiodes](/source/Photodiode). Each of the 12 silicon diodes are designed to be sensitive to different frequencies of light.

Several broad band diodes (designated BB1, BB2, BB3, and BB4) are placed to focus accurately at distances between six and 43 feet away from the lander.[28] A low resolution broad band diode was named SURVEY.[28] There are also three narrow band low resolution diodes (named BLUE, GREEN and RED) for obtaining [color images](/source/RGB_color_model), and another three (IR1, IR2, and IR3) for [infrared](/source/Infrared) imagery.[28]

The cameras scanned at a rate of five vertical scan lines per second, each composed of 512 pixels. The 300 degree panorama images were composed of 9150 lines. The cameras' scan was slow enough that in a crew shot taken during development of the imaging system several members show up several times in the shot as they moved themselves as the camera scanned.[29][30]

### Mass Breakdown of Viking Landers

Item Mass, kg (lb)[31] Structures and Mechanisms 132 kg (291 lb) Propulsion 56 kg (123 lb) Pyro and Cabling 43 kg (95 lb) Thermal Control 36 kg (79 lb) Guidance and Control 79 kg (174 lb) Power 103 kg (227 lb) Communications / Telemetry 57 kg (126 lb) Science Instruments 91 kg (201 lb) =Total Dry Mass 595 kg (1,312 lb) +Landing Propellant (incl. ~15 kg (33 lb) residuals) 84 kg (185 lb) +Decelerator (incl.lander deorbit propellant) 118 kg (260 lb) +Aeroshell 269 kg (593 lb) +Bioshield 74 kg (163 lb) +Cap 54 kg (119 lb) =Total Launch Mass (Lander+Flight Capsule) 1,194 kg (2,632 lb)

Viking control room at the [Jet Propulsion Laboratory](/source/Jet_Propulsion_Laboratory), days before the landing of Viking 1.

## Control systems

The Viking landers used a Guidance, Control and Sequencing Computer (GCSC) consisting of two [Honeywell](/source/Honeywell) HDC 402 24-bit computers with 18K of [plated-wire memory](/source/Plated_wire_memory), while the Viking orbiters used a Command Computer Subsystem (CCS) using two custom-designed 18-bit serial processors.[32][33][34]

## Financial cost of the Viking program

The two orbiters cost US$217 million at the time, which is about $1 billion in 2024 dollars.[35][36] The most expensive single part of the program was the lander's life-detection unit, which cost about $60 million then or $400 million in 2024 dollars.[35][36] Development of the Viking lander design cost $357 million.[35] This was decades before NASA's ["faster, better, cheaper" approach](/source/%22Faster%2C_better%2C_cheaper%22_approach), and Viking needed to pioneer unprecedented technologies under national pressure brought on by the [Cold War](/source/Cold_War) and the aftermath of the [Space Race](/source/Space_Race), all under the prospect of possibly discovering extraterrestrial life for the first time.[35] The experiments had to adhere to a special 1971 directive that mandated that no single failure shall stop the return of more than one experiment—a difficult and expensive task for a device with over 40,000 parts.[35]

The Viking camera system cost $27.3 million to develop, or about $200 million in 2024 dollars.[35][36] When the Imaging system design was completed, it was difficult to find anyone who could manufacture its advanced design.[35] The program managers were later praised for fending off pressure to go with a simpler, less advanced imaging system, especially when the views rolled in.[35] The program did however save some money by cutting out a third lander and reducing the number of experiments on the lander.[35]

Overall NASA says that $1 billion in 1970s dollars was spent on the program,[5][6] which when inflation-adjusted to 2024 dollars is about $6 billion.[36]

## Mission end

The craft all eventually failed, one by one, as follows:[1] Craft Arrival date Shut-off date Operational lifetime Cause of failure Viking 2 orbiter August 7, 1976 July 25, 1978 1 year, 11 months, 18 days Shut down after fuel leak in propulsion system. Viking 2 lander September 3, 1976 April 11, 1980 3 years, 7 months, 8 days Shut down after battery failure. Viking 1 orbiter June 19, 1976 August 17, 1980 4 years, 1-month, 19 days Shut down after depletion of attitude control fuel. Viking 1 lander July 20, 1976 November 13, 1982 6 years, 3 months, 22 days Shut down after human error during software update caused the lander's antenna to go down, terminating power and communication.

The Viking program ended on May 21, 1983. To prevent an imminent impact with Mars the orbit of *Viking 1* orbiter was raised on August 7, 1980, before it was shut down 10 days later. Impact and potential contamination on the planet's surface is possible from 2019 onwards.[5]

The *Viking 1* lander was found to be about 6 kilometers from its planned landing site by the [Mars Reconnaissance Orbiter](/source/Mars_Reconnaissance_Orbiter) in December 2006.[37]

## Message artifact

See also: [List of extraterrestrial memorials](/source/List_of_extraterrestrial_memorials)

Each 'Viking' lander carried a tiny dot of microfilm containing the names of several thousand people who had worked on the mission.[38] Several earlier and later space probes had carried message artifacts, such as the [Pioneer plaque](/source/Pioneer_plaque) and the [Voyager Golden Record](/source/Voyager_Golden_Record). Later probes also carried memorials or lists of names, such as the [*Perseverance*](/source/Perseverance_(rover)) rover which recognizes the almost 11 million people who [signed up to include their names](/source/Perseverance_(rover)#Commemorative_artifacts) on the mission.

## See also

- [Exploration of Mars](/source/Exploration_of_Mars)

- [Life on Mars](/source/Life_on_Mars) – Assessments of possible life on Mars

- [List of missions to Mars](/source/List_of_missions_to_Mars)

- [Mars Science Laboratory](/source/Mars_Science_Laboratory) – Robotic mission that deployed the *Curiosity* rover to Mars in 2012

- [Mars Pathfinder](/source/Mars_Pathfinder) – Mission including first robotic rover to operate on Mars (1997)

- [Norman L. Crabill](/source/Norman_L._Crabill) – NASA engineer (1926–2024)

## References

1. ^ [***a***](#cite_ref-NASA-20061218_1-0) [***b***](#cite_ref-NASA-20061218_1-1) [***c***](#cite_ref-NASA-20061218_1-2) [***d***](#cite_ref-NASA-20061218_1-3) [***e***](#cite_ref-NASA-20061218_1-4) [***f***](#cite_ref-NASA-20061218_1-5) [***g***](#cite_ref-NASA-20061218_1-6) [***h***](#cite_ref-NASA-20061218_1-7) [***i***](#cite_ref-NASA-20061218_1-8) [***j***](#cite_ref-NASA-20061218_1-9) Williams, David R. Dr. (December 18, 2006). ["Viking Mission to Mars"](https://nssdc.gsfc.nasa.gov/planetary/viking.html). [NASA](/source/NASA). [Archived](https://web.archive.org/web/20231206095644/https://nssdc.gsfc.nasa.gov/planetary/viking.html) from the original on December 6, 2023. Retrieved February 2, 2014.

1. **[^](#cite_ref-NASA-Viking1_2-0)** Nelson, Jon. ["Viking 1"](https://www.jpl.nasa.gov/missions/viking-1). [JPL](/source/JPL). [Archived](https://web.archive.org/web/20231024145216/https://www.jpl.nasa.gov/missions/viking-1) from the original on October 24, 2023. Retrieved February 2, 2014.

1. **[^](#cite_ref-NASA-Viking2_3-0)** Nelson, Jon. ["Viking 2"](https://www.jpl.nasa.gov/missions/viking-2). [JPL](/source/JPL). [Archived](https://web.archive.org/web/20231008204431/https://www.jpl.nasa.gov/missions/viking-2) from the original on October 8, 2023. Retrieved February 2, 2014.

1. **[^](#cite_ref-SoffenViking1978_4-0)** Soffen, G. A. (July–August 1978). "Mars and the Remarkable Viking Results." *Journal of Spacecraft and Rockets*. **15** (4): 193-200.

1. ^ [***a***](#cite_ref-nssdc-viking1orbiter_5-0) [***b***](#cite_ref-nssdc-viking1orbiter_5-1) [***c***](#cite_ref-nssdc-viking1orbiter_5-2) ["Viking 1 Orbiter spacecraft details"](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1975-075A). *[NASA Space Science Data Coordinated Archive](/source/NASA_Space_Science_Data_Coordinated_Archive)*. NASA. March 20, 2019. Retrieved July 10, 2019.

1. ^ [***a***](#cite_ref-space.com_6-0) [***b***](#cite_ref-space.com_6-1) Howell, Elizabeth (October 26, 2012). ["Viking 1: First U.S. Lander on Mars"](https://www.space.com/18234-viking-1.html). *[Space.com](/source/Space.com)*. [Archived](https://web.archive.org/web/20230906024226/https://www.space.com/18234-viking-1.html) from the original on September 6, 2023. Retrieved December 13, 2016.

1. **[^](#cite_ref-inflation-USGDP_7-0)** Johnston, Louis; Williamson, Samuel H. (2023). ["What Was the U.S. GDP Then?"](http://www.measuringworth.com/datasets/usgdp/). *[MeasuringWorth](/source/MeasuringWorth)*. Retrieved November 30, 2023. United States [Gross Domestic Product deflator](/source/Gross_Domestic_Product_deflator) figures follow the *MeasuringWorth* series.

1. **[^](#cite_ref-cps-viking_8-0)** ["The Viking Program"](https://planetary-science.org/mars-research/mars-landings/the-viking-program/). The Center for Planetary Science. [Archived](https://web.archive.org/web/20231120170823/http://planetary-science.org/mars-research/mars-landings/the-viking-program/) from the original on November 20, 2023. Retrieved April 13, 2018.

1. **[^](#cite_ref-csc-viking-lander_9-0)** ["Viking Lander"](https://californiasciencecenter.org/exhibits/air-space/mission-planets/viking-lander). [California Science Center](/source/California_Science_Center). July 3, 2014. [Archived](https://web.archive.org/web/20230527121521/https://californiasciencecenter.org/exhibits/air-space/mission-planets/viking-lander) from the original on May 27, 2023. Retrieved April 13, 2018.

1. **[^](#cite_ref-jpl-factsheet-viking_10-0)** ["Viking Fact Sheet"](https://web.archive.org/web/20120310184911/https://www.jpl.nasa.gov/news/fact_sheets/viking.pdf) (PDF). [Jet Propulsion Laboratory](/source/Jet_Propulsion_Laboratory). Archived from [the original](https://www.jpl.nasa.gov/news/fact_sheets/viking.pdf) (PDF) on March 10, 2012. Retrieved March 27, 2012.

1. **[^](#cite_ref-Kieffer1992_11-0)** Kieffer, Hugh H.; Jakosky, Bruce M.; Snyder, Conway W.; Matthews, Mildred S., eds. (1992). [*Mars*](https://archive.org/details/marsspacescience00unse). [University of Arizona Press](/source/University_of_Arizona_Press). [ISBN](/source/ISBN_(identifier)) [978-0-8165-1257-7](https://en.wikipedia.org/wiki/Special:BookSources/978-0-8165-1257-7). [LCCN](/source/LCCN_(identifier)) [92010951](https://lccn.loc.gov/92010951). Retrieved March 7, 2011.

1. **[^](#cite_ref-raeburn-1998_12-0)** Raeburn, Paul (1998). Mulroy, Kevin (ed.). [*Mars: Uncovering the Secrets of the Red Planet*](https://archive.org/details/marsuncoveringse00raeb). [National Geographic Society](/source/National_Geographic_Society). [ISBN](/source/ISBN_(identifier)) [0-7922-7373-7](https://en.wikipedia.org/wiki/Special:BookSources/0-7922-7373-7). [LCCN](/source/LCCN_(identifier)) [98013991](https://lccn.loc.gov/98013991).

1. **[^](#cite_ref-moore-1990_13-0)** Moore, Patrick; Hunt, Garry; Nicolson, Iain; Cattermole, Peter (1990). Garlick, Judy (ed.). [*The Atlas of the Solar System*](https://archive.org/details/atlasofsolarsyst0000unse_o5j4). [Mitchell Beazley](/source/Mitchell_Beazley). [ISBN](/source/ISBN_(identifier)) [0-86134-125-2](https://en.wikipedia.org/wiki/Special:BookSources/0-86134-125-2).

1. **[^](#cite_ref-morton-2002_14-0)** Morton, Oliver (2002). [*Mapping Mars: Science, Imagination, and the Birth of a World*](https://archive.org/details/mappingmarsscien00mort_0). [Picador](/source/Picador_(imprint)). [ISBN](/source/ISBN_(identifier)) [0-312-24551-3](https://en.wikipedia.org/wiki/Special:BookSources/0-312-24551-3).

1. **[^](#cite_ref-15)** Hearst Magazines (June 1976). ["Amazing Search for Life On Mars"](https://books.google.com/books?id=aOIDAAAAMBAJ&pg=PA66). *Popular Mechanics*. Hearst Magazines. pp. 61–63.

1. **[^](#cite_ref-science-19760827_16-0)** Soffen, G. A.; Snyder, C. W. (August 27, 1976). ["The First Viking Mission to Mars"](https://www.science.org/doi/10.1126/science.193.4255.759). *[Science](/source/Science_(journal))*. **193** (4255): 759–766. [Bibcode](/source/Bibcode_(identifier)):[1976Sci...193..759S](https://ui.adsabs.harvard.edu/abs/1976Sci...193..759S). [doi](/source/Doi_(identifier)):[10.1126/science.193.4255.759](https://doi.org/10.1126%2Fscience.193.4255.759). [PMID](/source/PMID_(identifier)) [17747776](https://pubmed.ncbi.nlm.nih.gov/17747776). [Archived](https://web.archive.org/web/20230211150701/https://www.science.org/doi/10.1126/science.193.4255.759) from the original on February 11, 2023. Retrieved December 21, 2023.

1. **[^](#cite_ref-britannica-carl-sagan_17-0)** Kragh, Helge. ["Carl Sagan"](https://www.britannica.com/biography/Carl-Sagan). *[Encyclopædia Britannica](/source/Encyclop%C3%A6dia_Britannica)*. [Archived](https://web.archive.org/web/20231108075739/https://www.britannica.com/biography/Carl-Sagan) from the original on November 8, 2023. Retrieved August 9, 2022.

1. **[^](#cite_ref-astro.if.ufrgs.br-viking_18-0)** ["Viking"](http://astro.if.ufrgs.br/solar/viking.htm). *astro.if.ufrgs.br*. [Archived](https://web.archive.org/web/20230813090441/http://astro.if.ufrgs.br/solar/viking.htm) from the original on August 13, 2023.

1. **[^](#cite_ref-19)** ["SNAP-19 Radioisotope Thermoelectric Generator Fact Sheet by Energy Research & Development Administration (ERDA) Diagram 2 - The Energy Research and Development Administration"](https://artsandculture.google.com/asset/_/twFyqw9QR3uOoQ). *Google Arts & Culture*. Retrieved August 9, 2022.

1. **[^](#cite_ref-Beegle_20-0)** BEEGLE, LUTHER W.; et al. (August 2007). "A Concept for NASA's Mars 2016 Astrobiology Field Laboratory". *Astrobiology*. **7** (4): 545–577. [Bibcode](/source/Bibcode_(identifier)):[2007AsBio...7..545B](https://ui.adsabs.harvard.edu/abs/2007AsBio...7..545B). [doi](/source/Doi_(identifier)):[10.1089/ast.2007.0153](https://doi.org/10.1089%2Fast.2007.0153). [PMID](/source/PMID_(identifier)) [17723090](https://pubmed.ncbi.nlm.nih.gov/17723090).

1. **[^](#cite_ref-latimes-20080806_21-0)** Johnson, John (August 6, 2008). ["Perchlorate found in Martian soil"](https://www.latimes.com/la-sci-phoenix6-2008aug06-story.html). *[Los Angeles Times](/source/Los_Angeles_Times)*. [Archived](https://web.archive.org/web/20230419020853/https://www.latimes.com/la-sci-phoenix6-2008aug06-story.html) from the original on April 19, 2023.

1. **[^](#cite_ref-sciencedaily-20080806_22-0)** ["Martian Life Or Not? NASA's Phoenix Team Analyzes Results"](https://www.sciencedaily.com/releases/2008/08/080805192122.htm). *Science Daily*. August 6, 2008. [Archived](https://web.archive.org/web/20231118165426/http://www.sciencedaily.com/releases/2008/08/080805192122.htm) from the original on November 18, 2023.

1. **[^](#cite_ref-23)** Navarro–Gonzáles, Rafael; Edgar Vargas; José de la Rosa; Alejandro C. Raga; Christopher P. McKay (December 15, 2010). ["Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars"](https://web.archive.org/web/20110109102058/http://www.agu.org/pubs/crossref/2010/2010JE003599.shtml). *Journal of Geophysical Research: Planets*. Vol. 115, no. E12010. Archived from [the original](http://www.agu.org/pubs/crossref/2010/2010JE003599.shtml) on January 9, 2011. Retrieved January 7, 2011.

1. **[^](#cite_ref-24)** Than, Ker (April 15, 2012). ["Life on Mars Found by NASA's Viking Mission"](https://web.archive.org/web/20120415072431/http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/). *National Geographic*. Archived from [the original](https://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/) on April 15, 2012. Retrieved April 13, 2018.

1. **[^](#cite_ref-Bianciardi-2012_25-0)** Bianciardi, Giorgio; Miller, Joseph D.; Straat, Patricia Ann; Levin, Gilbert V. (March 2012). ["Complexity Analysis of the Viking Labeled Release Experiments"](https://doi.org/10.5139%2FIJASS.2012.13.1.14). *IJASS*. **13** (1): 14–26. [Bibcode](/source/Bibcode_(identifier)):[2012IJASS..13...14B](https://ui.adsabs.harvard.edu/abs/2012IJASS..13...14B). [doi](/source/Doi_(identifier)):[10.5139/IJASS.2012.13.1.14](https://doi.org/10.5139%2FIJASS.2012.13.1.14). [hdl](/source/Hdl_(identifier)):[11365/27718](https://hdl.handle.net/11365%2F27718).

1. **[^](#cite_ref-Discovery-20120412_26-0)** Klotz, Irene (April 12, 2012). ["Mars Viking Robots 'Found Life'"](https://web.archive.org/web/20120414163121/http://news.discovery.com/space/mars-life-viking-landers-discovery-120412.html). [DiscoveryNews](/source/Discovery_Channel). Archived from [the original](http://news.discovery.com/space/mars-life-viking-landers-discovery-120412.html) on April 14, 2012. Retrieved April 16, 2012.

1. **[^](#cite_ref-27)** Guzman, Melissa; McKay, Christopher P.; Quinn, Richard C.; Szopa, Cyril; Davila, Alfonso F.; Navarro-González, Rafael; Freissinet, Caroline (2018). ["Identification of Chlorobenzene in the Viking Gas Chromatograph-Mass Spectrometer Data Sets: Reanalysis of Viking Mission Data Consistent With Aromatic Organic Compounds on Mars"](https://hal-insu.archives-ouvertes.fr/insu-01820363/file/2018JE005544.pdf) (PDF). *Journal of Geophysical Research: Planets*. **123** (7): 1674–1683. [Bibcode](/source/Bibcode_(identifier)):[2018JGRE..123.1674G](https://ui.adsabs.harvard.edu/abs/2018JGRE..123.1674G). [doi](/source/Doi_(identifier)):[10.1029/2018JE005544](https://doi.org/10.1029%2F2018JE005544). [ISSN](/source/ISSN_(identifier)) [2169-9100](https://search.worldcat.org/issn/2169-9100). [S2CID](/source/S2CID_(identifier)) [133854625](https://api.semanticscholar.org/CorpusID:133854625). [Archived](https://web.archive.org/web/20201103090059/https://hal-insu.archives-ouvertes.fr/insu-01820363/file/2018JE005544.pdf) (PDF) from the original on November 3, 2020.

1. ^ [***a***](#cite_ref-:1_28-0) [***b***](#cite_ref-:1_28-1) [***c***](#cite_ref-:1_28-2) ["PDS: Instrument Information"](https://pds.nasa.gov/ds-view/pds/viewInstrumentProfile.jsp?INSTRUMENT_ID=CAM1&INSTRUMENT_HOST_ID=VL1). *pds.nasa.gov*. Retrieved March 28, 2023.

1. **[^](#cite_ref-29)** The Viking Lander Imaging Team (1978). ["Chapter 8: Cameras Without Pictures"](https://history.nasa.gov/SP-425/ch8.htm). *The Martian Landscape*. NASA. p. 22.

1. **[^](#cite_ref-nytimes-19760721_30-0)** McElheny, Victor K. (July 21, 1976). ["Viking Cameras Light in Weight, Use Little Power, Work Slowly"](https://www.nytimes.com/1976/07/21/archives/viking-cameras-light-in-weight-use-little-power-work-slowly.html). *[The New York Times](/source/The_New_York_Times)*. [Archived](https://web.archive.org/web/20210222145516/https://www.nytimes.com/1976/07/21/archives/viking-cameras-light-in-weight-use-little-power-work-slowly.html) from the original on February 22, 2021. Retrieved September 28, 2013.

1. **[^](#cite_ref-MarsLanderRetroprop_31-0)** ["Mars Lander Retro Propulsion (IAF-99-S.2.02)"](https://www.researchgate.net/publication/232617757). Retrieved May 14, 2024.

1. **[^](#cite_ref-nasa-computers_32-0)** Tomayko, James (March 1988). [*Computers in Spaceflight: The NASA Experience*](https://history.nasa.gov/computers/Ch5-6.html) (Technical report). [NASA](/source/NASA). CR-182505. [Archived](https://web.archive.org/web/20230506223908/https://history.nasa.gov/computers/Ch5-6.html) from the original on May 6, 2023. Retrieved February 6, 2010.

1. **[^](#cite_ref-33)** Holmberg, Neil A.; Robert P. Faust; H. Milton Holt (November 1980). ["NASA Reference Publication 1027: Viking '75 spacecraft design and test summary. Volume 1 – Lander design"](https://ntrs.nasa.gov/api/citations/19810001592/downloads/19810001592.pdf) (PDF). NASA. Retrieved February 6, 2010.

1. **[^](#cite_ref-34)** Holmberg, Neil A.; Robert P. Faust; H. Milton Holt (November 1980). ["NASA Reference Publication 1027: Viking '75 spacecraft design and test summary. Volume 2 – Orbiter design"](https://ntrs.nasa.gov/api/citations/19810001593/downloads/19810001593.pdf) (PDF). NASA. Retrieved February 6, 2010.

1. ^ [***a***](#cite_ref-marsmoney_35-0) [***b***](#cite_ref-marsmoney_35-1) [***c***](#cite_ref-marsmoney_35-2) [***d***](#cite_ref-marsmoney_35-3) [***e***](#cite_ref-marsmoney_35-4) [***f***](#cite_ref-marsmoney_35-5) [***g***](#cite_ref-marsmoney_35-6) [***h***](#cite_ref-marsmoney_35-7) [***i***](#cite_ref-marsmoney_35-8) McCurdy, Howard E. (2001). [*Faster, Better, Cheaper: Low-Cost Innovation in the U.S. Space Program*](https://books.google.com/books?id=5Dy6z6DQDNoC&pg=PA68). JHU Press. p. 68. [ISBN](/source/ISBN_(identifier)) [978-0-8018-6720-0](https://en.wikipedia.org/wiki/Special:BookSources/978-0-8018-6720-0).

1. ^ [***a***](#cite_ref-:0_36-0) [***b***](#cite_ref-:0_36-1) [***c***](#cite_ref-:0_36-2) [***d***](#cite_ref-:0_36-3) As the Viking program was a government expense, the inflation index of the United States [Nominal Gross Domestic Product](/source/Nominal_GDP) per capita is used for the inflation-adjusting calculation.

1. **[^](#cite_ref-37)** Chandler, David (December 5, 2006). ["Probe's powerful camera spots Vikings on Mars"](https://www.newscientist.com/article/dn10727-probes-powerful-camera-spots-vikings-on-mars.html#.UlIB7FDrwbN). *New Scientist*. Retrieved October 8, 2013.

1. **[^](#cite_ref-38)** ["Visions of Mars: Then and Now"](https://www.planetary.org/outreach/visions-of-mars-then-and-now). *The Planetary Society*.

## Further reading

- [On Mars: Exploration of the Red Planet](https://www.hq.nasa.gov/office/pao/History/SP-4212/on-mars.html) [Archived](https://web.archive.org/web/20070205092559/http://www.hq.nasa.gov/office/pao/History/SP-4212/on-mars.html) February 5, 2007, at the [Wayback Machine](/source/Wayback_Machine)

- [Viking Orbiter Views of Mars](https://history.nasa.gov/SP-441/cover.htm)

- [The Martian Landscape SP-425](https://history.nasa.gov/SP-425/cover.htm)

- [*Analytical Chemistry* feature article about the Viking spacecraft's scientific mission](http://pubs.acs.org/subscribe/journals/ancham/79/i19/pdf/1007feature_viking.pdf)

- [Viking '75 spacecraft design and test summary. Volume 1 Lander design – NASA Report](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810001592_1981001592.pdf) [Archived](https://web.archive.org/web/20201027065224/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810001592_1981001592.pdf) October 27, 2020, at the [Wayback Machine](/source/Wayback_Machine)

- [Viking '75 spacecraft design and test summary. Volume 2 Orbiter design – NASA Report](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810001593_1981001593.pdf) [Archived](https://web.archive.org/web/20201027062855/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810001593_1981001593.pdf) October 27, 2020, at the [Wayback Machine](/source/Wayback_Machine)

- [Viking '75 spacecraft design and test summary. Volume 3 Engineering test summary – NASA Report](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810002594_1981002594.pdf) [Archived](https://web.archive.org/web/20201028054352/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810002594_1981002594.pdf) October 28, 2020, at the [Wayback Machine](/source/Wayback_Machine)

## External links

Wikimedia Commons has media related to [Viking mission](https://commons.wikimedia.org/wiki/Category:Viking_mission).

- [NASA Mars Viking Mission](https://www.nasa.gov/mission_pages/viking/) [Archived](https://web.archive.org/web/20070223062630/http://www.nasa.gov/mission_pages/viking/) February 23, 2007, at the [Wayback Machine](/source/Wayback_Machine)

- [Viking Mission to Mars (NASA SP-334)](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740026174_1974026174.pdf) [Archived](https://web.archive.org/web/20130807125926/http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740026174_1974026174.pdf) August 7, 2013, at the [Wayback Machine](/source/Wayback_Machine)

- [Solar Views Project Viking Fact Sheet](http://www.solarviews.com/span/vikingfs.htm)

- [Viking Mission to Mars](http://www.maniacworld.com/Viking-Mission-to-Mars.htm) [Archived](https://web.archive.org/web/20110716215016/http://www.maniacworld.com/Viking-Mission-to-Mars.htm) July 16, 2011, at the [Wayback Machine](/source/Wayback_Machine) Video

- [A diagram of the Viking and its flight profile](http://www.flightglobal.com/airspace/photos/missilespacesystemscutaways/nasa-viking-cutaway-10304.aspx)

- [Article at Smithsonian Air and Space Website](https://web.archive.org/web/20150117191711/http://airandspace.si.edu/exhibitions/exploring-the-planets/online/mars/viking_lab.html)

- [The Viking Mars Missions Education & Preservation Project (VMMEPP)](https://vikingpreservationproject.org/)

- [VMMEPP Online exhibit](https://artsandculture.google.com/exhibit/the-viking-mars-mission-the-viking-mars-missions-education-and-preservation-project/RQKiJsUJbOktIw?hl=en)

- [45 years ago: *Viking* 1 Touches Down on Mars](https://www.nasa.gov/feature/45-years-ago-viking-1-touches-down-on-mars)

v t e Viking Mars landers Viking program Viking 1 Viking 2 Viking lander biological experiments Related Exploration of Mars Jet Propulsion Laboratory

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v t e NASA Policy and history History (creation) NACA (1915) National Aeronautics and Space Act (1958) Space Task Group (1958) Paine (1986) Rogers (1986) Ride (1987) Space Exploration Initiative (1989) Augustine (1990) U.S. National Space Policy (1996) CFUSAI (2002) CAIB (2003) Vision for Space Exploration (2004) Aldridge (2004) Augustine (2009) General Space Race Administrator and Deputy Administrator Chief Scientist Astronaut Corps Ranks and positions Chief Budget NASA research spinoff technologies NASA+ NASA TV NASA Social Launch Services Program Mercury Control Center Manned Space Flight Network Kennedy Space Center Vehicle Assembly Building Launch Complex 39 39A 39B Launch Complex 48 Launch Control Center Operations and Checkout Building Johnson Space Center Mission Control Lunar Sample Laboratory Science Mission Directorate Human spaceflight programs Past X-15 (suborbital) Mercury Gemini Apollo Skylab Apollo–Soyuz (with the Soviet space program) Space Shuttle Shuttle–Mir (with Roscosmos) Constellation Current International Space Station Commercial Orbital Transportation Services Commercial Crew Orion Artemis Robotic programs Past Hitchhiker Mariner Mariner Mark II MESUR Mars Surveyor '98 New Millennium Lunar Orbiter Pioneer Planetary Observer Ranger Surveyor Viking Project Prometheus Mars Exploration Mars Exploration Rover Current Living With a Star Lunar Precursor Robotic Program Earth Observing System Great Observatories program Explorers Voyager Discovery New Frontiers Solar Terrestrial Probes Commercial Lunar Payload Services SIMPLEx Individual featured missions (human and robotic) Past Apollo 11 Artemis II COBE Mercury 3 Mercury-Atlas 6 Magellan Pioneer 10 Pioneer 11 Galileo timeline GALEX GRAIL WMAP Space Shuttle Spitzer Space Telescope Sojourner rover Spirit rover LADEE MESSENGER Aquarius Cassini Dawn Kepler space telescope Opportunity rover timeline observed RHESSI MAVEN InSight Ingenuity helicopter flights Currently operating Mars Reconnaissance Orbiter 2001 Mars Odyssey New Horizons International Space Station Hubble Space Telescope Chandra X-ray Observatory Swift Observatory THEMIS Curiosity rover timeline Lunar Reconnaissance Orbiter SDO Juno Mars Science Laboratory timeline NuSTAR Voyager 1 Voyager 2 MMS OSIRIS-APEX TESS Mars 2020 Perseverance rover timeline James Webb Space Telescope timeline PACE Europa Clipper NISAR Future Nancy Grace Roman Space Telescope DAVINCI VERITAS Communications and navigation Near Earth Network Space Network Deep Space Network (Goldstone Madrid Canberra Space Flight Operations Facility) Deep Space Atomic Clock NASA lists Astronauts by name by year Gemini astronauts Apollo astronauts Space Shuttle crews NASA aircraft NASA missions uncrewed missions Apollo missions Space Shuttle missions United States rockets NASA cancellations NASA cameras on spacecraft NASA images and artwork Earthrise The Blue Marble Family Portrait Pale Blue Dot Pillars of Creation Mystic Mountain Solar System Family Portrait The Day the Earth Smiled Hello, World Earthset Fallen Astronaut Deep fields Lunar plaques Pioneer plaques Voyager Golden Record Apollo 11 goodwill messages NASA insignia Gemini and Apollo medallions Mission patches Astronomy Picture of the Day Hubble Space Telescope anniversary images Related "We choose to go to the Moon" "One small step" Apollo 8 Genesis reading Apollo 15 postal covers incident Apollo Lunar Module Space Mirror Memorial The Astronaut Monument Lunar sample displays Moon rocks stolen or missing U.S. Astronaut Hall of Fame Space program on U.S. stamps Apollo 17 Moon mice Moon tree Other primates in space NASA Exoplanet Archive NASA International Space Apps Challenge Astronauts Day National Astronaut Day Nikon NASA F4 Category

v t e NASA planetary exploration programs Active Large strategic science missions Lunar Discovery & Exploration Mars Exploration Planetary Missions Discovery New Frontiers Solar System Exploration Ocean Worlds Exploration Voyager Completed Lunar Orbiter Lunar Precursor Mariner MESUR New Millennium Pioneer Planetary Observer Ranger Surveyor Viking Cancelled Grand Tour Mariner Mark II Project Prometheus Voyager (Mars) List of NASA missions

v t e Spacecraft missions to Mars List of missions to Mars List of Mars orbiters List of artificial objects on Mars Active Orbiters 2001 Mars Odyssey Mars Express Mars Reconnaissance Orbiter timeline Trace Gas Orbiter Hope Tianwen-1 orbiter ESCAPADE (enroute) Rovers Curiosity Mars Science Laboratory timeline Perseverance Mars 2020 timeline Past Flybys Mars 1† Mariner 4 Zond 2† Mariner 6 and 7 Mars 6 Mars 7 Rosetta‡ Dawn‡ Mars Cube One Europa Clipper‡ Hera‡ Psyche‡ Orbiters Mars 2 Mars 3 Mariner 9 Mars 4† Mars 5 Viking program Viking 1 Viking 2 Phobos program Phobos 1† Phobos 2† Mars Observer† Mars Global Surveyor Nozomi† Mars Climate Orbiter† Mangalyaan MAVEN Landers Mars 2† Mars 3† Mars 6† Mars 7† Viking 1 Viking 2 Mars Pathfinder Mars Polar Lander† / Deep Space 2† Beagle 2† Phoenix ExoMars Schiaparelli† InSight Tianwen-1 lander Rovers PrOP-M† Sojourner Mars Exploration Rover Spirit timeline Opportunity timeline Zhurong Aircraft Ingenuity helicopter flights Mars 2020 Failed launches Mars 1M No.1 1M No.2 2MV-4 No.1 2MV-3 No.1 Mariner 3 Mars 2M No.521 2M No.522 Mariner 8 Mars 3MS No.170 Mars 96 Fobos-Grunt / Yinghuo-1 Future Planned Martian Moons eXploration (MMX) and Idefix (Phobos rover) (2026) Tianwen-3 (2028) Rosalind Franklin (2028) MBR Explorer‡ (2028, flyby in 2031) Mangalyaan-2 (2031) Proposed LightShip (2032) MAGGIE SpaceX Mars program Tera-hertz Explorer (TEREX) Cancelled or not developed Aerial Regional-scale Environmental Survey Astrobiology Field Laboratory Beagle 3 Biological Oxidant and Life Detection DePhine ExoLance Icebreaker Life Kazachok Marsokhod Mars 4NM & 5NM Mars 5M (Mars-79) Mars-Aster Mars Astrobiology Explorer-Cacher (MAX-C) Mars Geyser Hopper Mars-Grunt Mars Exploration Ice Mapper Mars One Mars Micro Orbiter NASA-ESA Mars Sample Return Mars Sample Recovery Helicopters Mars Surveyor Lander Mars Telecommunications Orbiter MELOS rover MetNet NetLander Northern Light Next Mars Orbiter PADME Phootprint Sample Collection for Investigation of Mars (SCIM) Sky-Sailor SpaceX Red Dragon Vesta Voyager Mars Exploration Concepts Flyby Orbiter Landing Sky crane Atmospheric entry Rover Aircraft Sample return Human mission Permanent settlement Colonization Life Terraforming Strategies Mars Scout Program Mars Exploration Program Mars Exploration Joint Initiative Mars Next Generation Advocacy The Mars Project The Case for Mars Inspiration Mars Mars Institute Mars Society Mars race Missions are ordered by launch date. Sign † indicates failure en route or before intended mission data returned. ‡ indicates use of the planet as a gravity assist en route to another destination.

Authority control databases International VIAF National United States Israel Other Yale LUX

[Portals](https://en.wikipedia.org/wiki/Wikipedia:Contents/Portals):
- [Astronomy](https://en.wikipedia.org/wiki/Portal:Astronomy)
- [Biology](https://en.wikipedia.org/wiki/Portal:Biology)
- [Solar System](https://en.wikipedia.org/wiki/Portal:Solar_System)

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Adapted from the Wikipedia article [Viking program](https://en.wikipedia.org/wiki/Viking_program) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Viking_program?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.