On a November day in 1971, a small NASA spacecraft named Mariner 9 slid into orbit around Mars, becoming the first machine built by human hands to circle another planet. It arrived beneath a planet-wide dust storm, and the early glimpses of tall shapes rising through the haze hinted at a world far stranger than the cratered, Moon-like sphere earlier flybys had suggested. In winning a close race against a Soviet probe, it also marked a quiet turning point in how humanity came to see its neighboring planet.
On This Day: Mariner 9 Becomes First Spacecraft to Orbit Mars, Revealing Its Volcanoes and Canyons
No longer a cratered, moon-like point of light, but a world
Mark
Why does this orbit matter more than the earlier flybys?
Mimi
Flybys gave quick glimpses, and those showed craters. Orbiting meant Mariner 9 could stay, wait out the dust storm, and map the planet.
Mark
And the dust storm turned out to be part of the story.
Mimi
Yes. The first sign of the volcanoes was their tops sticking up through the clouds. Later images showed what they were.
Luke
Worth noting the source gives Olympus Mons as the tallest volcano in the solar system, and Valles Marineris as five times the Grand Canyon's length. Those are stated, not walked through.
Mark
What about the race with the Soviet Union?
Mimi
Mars 2 had an 11-day head start, per NASA's mission description, but Mariner 9 arrived first. Mars 2 crashed into the surface, which made it the first human-built object to reach Mars that way.
Luke
Careful, though: that 11-day figure comes from NASA's own description. We don't have a Soviet account here.
Mark
How much did Mariner 9 actually cover?
Mimi
About 85% of Mars, with 7,329 surface photos and at least 80 of Phobos and Deimos.
Luke
The resolution was 1 to 2 km, so that's broad mapping, not fine detail. And it ended because it ran out of nitrogen for its thrusters by February 1972, with the formal shutdown in October.
El Pulso
- A planet-wide dust storm hid Mars from view just as Mariner 9 arrived, leaving its first sightings as puzzling silhouettes above the clouds.
- Earlier flybys had painted Mars as a cratered, Moon-like world, and that old picture was about to be challenged.
- Mariner 9 raced the Soviet Mars 2 to orbit, arriving first despite Mars 2's 11-day head start.
- Its images revealed giant volcanoes, including Olympus Mons, and the vast Valles Marineris canyon, reshaping scientific understanding of the planet.
- After mapping about 85 percent of Mars and sending back 7,329 photos, the mission wound down as its nitrogen ran out, and NASA formally ended it in October 1972.
On a November day in 1971, a small NASA spacecraft named Mariner 9 slid into orbit around Mars, becoming the first machine built by human hands to circle another planet. It arrived beneath a planet-wide dust storm, and the early glimpses of tall shapes rising through the haze hinted at a world far stranger than the cratered, Moon-like sphere earlier flybys had suggested. In winning a close race against a Soviet probe, it also marked a quiet turning point in how humanity came to see its neighboring planet.
On Nov. 13, 1971, NASA's Mariner 9 slipped into orbit around Mars, the first human-built craft to circle another planet. It arrived inside a planet-wide dust storm, and the first things it glimpsed were a few tall structures poking up through the clouds rather than a surface at all.
Earlier NASA flybys had shown a cratered landscape, and some scientists had concluded Mars looked much like the Moon. Mariner 9 overturned that view. Its images revealed enormous volcanoes, including Olympus Mons, the tallest volcano in the solar system, and helped map Valles Marineris, a canyon stretching across the Tharsis region.
The mission also won a race. The Soviet Mars 2 had left Earth with an 11-day head start, yet Mariner 9 reached Mars first. Mars 2 later became the first human-built object to hit the Martian surface.
Over nearly a year, Mariner 9 mapped about 85 percent of the planet and took 7,329 photos, along with at least 80 images of Mars's moons, Phobos and Deimos. Its end came quietly: by February 1972 it had exhausted the gaseous nitrogen that fueled its orientation thrusters, and NASA formally closed the mission in October 1972. What it left behind was a new Mars, no longer a dim, moon-like point of light but a world of giant volcanoes and a vast canyon.
On Nov. 13, 1971, a NASA spacecraft called Mariner 9 slipped into orbit around Mars, the first human-built craft to circle another planet. It arrived into a planet-wide dust storm, and the first thing it saw was not a surface at all, but a few tall structures poking up through the clouds.
Before Mariner 9, NASA had sent several Mars flybys. Those brief passes showed a cratered surface, and some scientists concluded that Mars looked much like the Moon. Mariner 9 overturned that idea.
The mission also won a race of sorts. The Soviet Union's Mars 2 left Earth with what NASA, in its mission description, called an 11-day head start. Mariner 9 still got to Mars first. Mars 2 went on to make history of its own, becoming the first human-built object to hit the Martian surface when it crashed into the planet.
When the dust cleared, Mariner 9's images showed that the structures seen through the clouds were the tops of enormous volcanoes. The probe discovered 20 giant volcanoes in all, among them Olympus Mons, the tallest volcano in the solar system. It also made the key observations used to map Valles Marineris, a canyon system that runs about 2,500 miles (4,000 kilometers) across the Tharsis region and is 120 miles (200 km) wide. The source describes it as five times longer than Arizona's Grand Canyon. NASA noted that the canyon was named in honor of Mariner 9.
The spacecraft carried four primary instruments: a camera system, an ultraviolet spectrometer, an infrared spectrometer and an infrared radiometer. With them it mapped 85% of Mars during a mission that lasted nearly a year. It took 7,329 photos of the surface, resolving features down to between 1/2 and 1 mile (1 to 2 km). It also captured at least 80 images of Phobos and Deimos, the two small moons of Mars.
The end came quietly. By February 1972, Mariner 9 had used up its gaseous nitrogen, which fed the thrusters that controlled its orientation. NASA formally shut the mission down in October 1972.
What the mission left behind was a change in how Mars was understood: no longer a cratered, moon-like point of light, but a world with giant volcanoes and a vast canyon, and one of the most famous Mars missions ever flown.
Citas Notables
The canyon was named in honor of Mariner 9.— NASA, in a mission overview
Mars 2 had an 11-day head start.— NASA, in a mission description
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