A U.S. Atlas V rocket lifted off from Florida's Cape Canaveral on July 30 to cap an unprecedented month of international Mars mission launches, including by the United Arab Emirates and China.
The current flurry of missions to the "red planet" reflects renewed efforts to determine whether a "warmer and wetter Mars" might have hosted ancient life and follows in the figurative tracks of four successful U.S. Mars rovers since 1997, along with some interplanetary missteps.
But the reemphasis on breaking new ground on Mars is also a reminder of one of Soviet scientists' most disappointing -- yet in major ways, successful -- episodes of the Space Race.
After a decade of misfires and failed flyby missions, the U.S.S.R. made 14 seconds of history in 1971, when its Mars 3 lander transmitted radio signals and a fuzzy image -- or signal -- from the surface of Mars before cutting out and going silent forever.
Then, almost without a trace, humankind's first controlled landing on the red planet and its lone image disappeared for decades after the malfunction amid one of the fiercest Martian dust storms that astronomers had ever witnessed.
The image finally resurfaced in the 1980s.
And more than two decades after that, NASA crowdsourced a massive, multibillion-pixel hunt for the debris of the muted Mars 3 lander in an image from its Mars Reconnaissance Orbiter.
After the near-miss of the Mars 3 mission, Soviet scientific planners made a few more stabs at that inner planet before instead turning their attention for the next decade to Earth's nearest neighbor, Venus.
"In what we call the Space Race, there were many subraces, and there were subraces to Venus and to Mars," Brian Harvey, an Irish writer on spaceflight and fellow of the British Interplanetary Society who has written and broadcast extensively on the Soviet space program, told RFE/RL.
"The Soviet space program did not lack in ambition, and the early sets of missions included landers as well as flyby missions," he said. "But things kind of came to a climax in 1971."
The 'Horizon' Image
Observers are divided over exactly what -- if anything -- the Mars 3 lander's TV camera captured on December 2, 1971, in the only image beamed from the surface of Mars before NASA's Mars Pathfinder mission in 1997.
It is not hard to see why.
Soviet scientists themselves concluded at the time that it had no information whatsoever in its 79 scan lines of imagery and, rather than keeping it secret simply believed it was of no value.
The lone image sent by the Mars 3 lander, showing either a Martian dust storm or radio "snow."
Soviet scientists themselves concluded at the time that it had no information whatsoever in its 79 scan lines of imagery and, rather than keeping it secret simply believed it was of no value.
The image was not made public until the late 1980s, when Soviet leader Mikhail Gorbachev encouraged increased scientific cooperation with the West.
"One of the features that I've noticed about the Soviet space program was that, first of all, if they didn't think a photograph was good enough, they didn't release it," said Harvey, who argues that many Soviet space secrets were "hidden in plain view."
"So it wasn't a question of it being secret; they just felt that it didn't tell you enough, give you enough detail. So, they took the decision for us -- wrongly in my view -- that they should just not release it. They wanted something that could show something very definite very quickly."
Some people still argue that rather than just radio "noise," its successfully transmitted portion shows the Martian horizon in a dust storm.
But NASA and National Geographic describe this image from the Viking Lander 1 on July 20, 1976, as the first ever of the surface of Mars.
This 1976 NASA image was the first to give a clearer view of the Martian landscape, from a low-lying plain called Chryse Planitia in the northern hemisphere of Mars.
Soft Landing, Harder Luck
The Mars 3 mission was the third in a three-pronged effort during 1971 to reach, orbit, map, and touch down on the planet.
Mars 2 and Mars 3 were nearly identical missions -- each with its own orbiter module and descent/lander module -- launched just days apart on May 19 and May 28, 1971, and competing with NASA's ill-fated Mariner 8 and vastly more successful Mariner 9 Mars missions for global attention.
Mars 2 and 3 were intended to piggyback on the Kosmos 419 mission, which was supposed to provide a radar beacon from orbit around Mars to help guide Mars 2 and Mars 3. But Kosmos 419 had crashed out of Earth's orbit soon after launch on May 12, leaving them to fend for themselves on the six-month journey to Mars.
Both had reached Mars orbit by late November.
Mars 2 crashed into the Martian landscape after entering the atmosphere at too steep an angle on November 27.
Five days later, the Mars 3 lander successfully navigated its 4-hour-plus descent from its orbiting platform to the Martian surface on December 2. It gradually opened its petal-like stabilizers and prepared to transmit.
V.G. Perminov, the leading designer for Mars and Venus spacecraft at the U.S.S.R.'s Lavochkin design offices in the early days of Martian and Venusian exploration, later detailed the moment of the lander's demise in a text called The Difficult Road To Mars.
Once the lander was stable on the surface, he said, "the transmission of panoramic images of the Martian surface recorded on the magnetic tape was initiated. The main engineer…who was standing close to the rack where the signal was displayed, gave a command to reduce the signal because it was too strong. Then the telephotometer data were transmitted. There was a gray background with no details.
"In 14.5 seconds, the signal disappeared. The same thing happened with the second telephotometer. Why did two telephotometers working in independent bands simultaneously fail within a hundredth of a second? We could not find an answer to this question."
Perminov drew a parallel with a World War II incident in which British radio signals were interrupted by electrical interference in a Lebanese dust storm.
Brian Harvey's photo of a model of the Mars 2 and Mars 3 landers on display in Moscow's Museum of Cosmonautics in 2009. He said he was prevented from taking a similar photo during a visit to the Soviet Union in 1988.
Most scientists agree that the dust storm somehow knocked out the lander's electrical system. Other theories include being struck by an object in the massive storm or failure as a result of being blown over by the wind.
It never appears to have gotten a chance to plant its Soviet pennant or deploy the PROP-M "rover," a box-like, 5-kilo robot tethered to the lander with 15 meters of cable that would allow it to "'walk' on a pair of skis" to collect soil and atmospheric samples.
Perminov would say one of its most important accomplishments "was that the scientifically and technically intricate problem of a soft landing on the Martian surface was solved."
Moreover, both the Mars 2 and 3 orbiters continued their missions orbiting Mars for about eight more months, snapping up images and providing other useful data that would contribute greatly to knowledge of the fourth planet from the sun.
Ground Control Saves Major Time
The Mars 3 landing remained mostly obscure to anyone but space-exploration devotees until a little over a decade ago.
But in 2007, U.S. researchers shared an image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter and unleashed a years-long scramble to find the silenced Soviet lander.
They titled it "Center of Soviet Mars 3 Landing Ellipse" to challenge the public to help scour the image's 1.8 billion pixels of data for Mars 3 or its wreckage.
The 2007 HiRISE image of Mars that set off the new search for the Mars 3 lander would take "about 2,500 typical computer screens" to view at full resolution, according to NASA.
It homed in on the Ptolemaeus Crater, a low-lying expanse of rock and dust that Soviet scientists pinpointed as the touchdown spot decades earlier.
In 2011, the epic crowdsourcing effort appeared to have paid off when a Russian known online as Imxotep reported spotting "light-colored debris" that measured about 8 meters by 8 meters and looked to be a Mars 3-style parachute. Imxotep suggested searching nearby for the lander itself.
Then, in April 2013, HiRISE said Russian space enthusiasts appeared to have spotted the lander, as well as its discarded retrorockets, heat shield and, yes, even its white parachute, on the Martian surface.
"Together, this set of features and their layout on the ground provide a remarkable match to what is expected from the Mars 3 landing, but alternative explanations for the features cannot be ruled out," NASA's Jet Propulsion Laboratory announced in April 2013. "Further analysis of the data and future images to better understand the 3-dimensional shapes may help to confirm this interpretation."
NASA issued a montage of the images and mostly left it at that.
: The NASA montage showing apparent parts of the Mars 3 lander and its retrorocket, heat shield, and parachute on the Martian surface in 2007.
The Russian space enthusiast who organized the VKontakte group that appeared to find the lander and its metal hardware, Vitaly Yegorov, chronicled the painstaking search.
In it, he described his surprise at learning that, with all the progress in space exploration, by 2012 no one had discovered the Mars 2 lander's final resting place.
"Our instrument, which accomplished a phenomenal achievement, the first-ever successful landing on another planet, more than 40 years ago!" he wrote, forgetting the success of a Soviet soft landing by Venera-7 on Venus in December 1970. "It did it in almost the same sequence that the Americans, in 2012, put [the Mars rover] Curiosity on the ground."
Keeping Pace In A Space Race
Since the Soviets had begun preparing for a Mars mission in 1959, Perminov wrote, "the United States had put humans on the Moon, and the Soviet Union had put a cosmonaut in space and circled the Moon with a satellite. However, sending a spacecraft to a distant planet and having it enter an unknown atmosphere and land on a poorly known surface was an undertaking of a different magnitude."
A few Soviet innovations had given momentum to their space program in the late 1960s, including what would become a vaunted reputation for rocket-engine manufacturing that continues to this day. (With varying degrees of controversy, U.S. rockets still use Russian engines; the U.S. Atlas V that blasted off carrying the Perseverance on July 30 was powered by the Russian RD-180 engine.)
A Soviet stamp from 1972 commemorating the Mars 3 mission.
The Proton rocket that the Soviet Union introduced in 1965 allowed for large payloads that could include tons of fuel and orbiters and landers along with their instruments to create images and to explore and measure topography, soil, and atmospheric composition.
And Soviet scientists had also developed an astronavigation system that was decades ahead of its rivals and allowed onboard computers to chart and steer its spacecraft using the position of stars and other celestial bodies.
Between the conception and realization of the first Mars landing, the Soviets had achieved a handful of firsts in their Venus program.
But for now, they were keen to repeat their Venus landing on another planet.
And 1971 was a particularly good year of what's known as "opposition," a phase when Earth and Mars are nearest to each other in their solar orbits. In fact, it was as close as those two neighboring, rocky planets had been in 47 years.
A view of the surface of Mars taken in 1965, six years before the Mars 2 and Mars 3 landers would get a lot closer.
But there were other time pressures, too.
With the Mars race in high gear, just two days after the Mars 3 launch an American orbiter -- Mariner 9 -- was lifting off that would go on to become the first spacecraft to orbit another planet and be enormously successful at mapping the red planet.
"The Russians, I think, felt that they should match that," Harvey said.
Perminov later acknowledged that some of the Soviet planners' key decisions on the Kosmos 419 and Mars 2 and 3 missions were influenced by a desire to outpace their U.S. counterparts, despite two dramatic launch failures of planned Mars orbiters in 1969.
Ironically, by the time the Mars 2 and Mars 3 orbiters were preparing to send their landers toward the planet in November and December 1971, Mariner 9 was in orbit around Mars and sending back images showing what Perminov would later describe as "an unusually strong dust storm," the likes of which "had never before been recorded on the Martian surface."