It's been 50 years since NASA sent Viking 1 on a mission to Mars.

[1]Launched on a Titan-Centaur rocket from Complex 41 at Cape Canaveral Air Force Station on August 20, 1975, Viking 1 was one of a pair of probes sent to land on Mars.

Viking 1 consisted of an orbiter and a lander and followed earlier US missions to Mars that had begun with Mariner 4 in 1964, continuing with the Mariner 6 and 7 flybys, and the Mariner 9 Mars orbital mission.

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Viking 1, however, would do more than orbit Mars. The project intended to send a lander to the surface, where the mission would continue for 90 days.

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Model of the Viking Lander (pic: NASA/JPL-Caltech/University of Arizona)

The first successful soft landing on Mars was achieved by a Soviet probe, Mars 3, which touched down on December 2, 1971. However, the lander only managed to operate for less than two minutes before communication was lost.

As it turned out, Viking 1 would endure far longer than that.

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The Viking 1 spacecraft arrived in orbit around Mars on June 19, 1976. The orbiter took images of the Martian surface that gave controllers pause for thought – the original landing site was deemed unsafe and an alternative was swiftly selected. Viking 1 landed the next day.

Viking 1's landing system was relatively straightforward compared to the sky crane used more recently for the Curiosity and Perseverance rovers. After separating from the orbiter, retrorockets were used to drop the lander out of orbit. An ablative heatshield provided protection during the plunge through the atmosphere before being jettisoned, and a parachute was deployed. Finally, retrorockets on the lander itself fired to ensure a relatively soft landing on the lander's three legs.

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The lander got to work, scooping up soil with its robotic arm for analysis and taking images of its surroundings. The lander had several science instruments on board, most of which returned more data than scientists had expected. The exception was the seismometer, which did not work after landing.

Power came from a pair of 35 W radioisotope thermoelectric generators (RTGs), connected in series on top of the lander. [7]According to NASA [PDF], "the computer was one of the greatest technical challenges of Viking." There were two general-purpose computer channels, each with a storage capacity of 18,000 words. One was active while the other was in reserve. There was also a tape recorder.

[8]Cape Canaveral marks 75 years since its first rocket launch

[9]Apollo-Soyuz at 50: The Cold War space hug that nearly ended in gasping horror

[10]60 years ago the US took its first walk in space with Gemini 4

[11]50 years ago the last Saturn rocket rolled out of NASA's Vehicle Assembly Building

Viking 1 was an unparalleled success. The orbiter and lander lasted far longer than initial expectations. The orbiter was eventually shut down in August 1980 after it ran out of attitude control propellant. It had begun to run low in 1978, but engineers were able to eke it out for a further two years. The lander kept on going until its final transmission on November 11, 1982.

Unfortunately, the lander's failure wasn't due to its hardware or the harsh environment of Mars. It was instead "a faulty command sent from Earth," [12]according to NASA . The command resulted in loss of communication. Controllers spent the next six and a half months attempting to regain contact with the lander before the overall mission came to an end on May 21, 1983.

It is debatable how much longer the lander could have lasted. Viking 2's lander transmitted data until April 12, 1980, but its batteries eventually failed. Both landers and their respective orbiters had operated far beyond their planned mission lifetimes.

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So, as NASA shifts its focus Mars-ward, please raise a glass to the anniversary of the launch of the agency's first successful mission to land on the red planet. ®

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[1] https://www.nasa.gov/image-article/viking-1-begins-journey-to-mars/

[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aKjod4KBSEbwgfM-heCw_gAAARE&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[3] https://regmedia.co.uk/2025/08/21/viking_lander_model.jpg

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[7] https://d2pn8kiwq2w21t.cloudfront.net/documents/viking_YBc3kvY.pdf

[8] https://www.theregister.com/2025/07/29/first_rocket_cape_canaveral/

[9] https://www.theregister.com/2025/07/14/50_apollo_soyuz/

[10] https://www.theregister.com/2025/06/04/first_us_spacewalk_60_years_ago/

[11] https://www.theregister.com/2025/03/26/50_years_since_last_saturn/

[12] https://science.nasa.gov/mission/viking-1/

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[14] https://whitepapers.theregister.com/