Previously lost Soviet Mars 3 lander discovered by Mars Orbiter

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On May 28, 1971, the former Soviet Union sent a lander to the Red Planet. Called the Mars 3, it followed the ill-fated and crashed Mars 2 to the planet, landing on the surface on December 2 of the same year and achieving the first successful soft landing on Mars in human history. The Mars 3 opened to release its PROP-M rover, transmitted for all of 14.5 secondsâ€"and fell silent. The craft has not been seen or heard from since.

Until now, that is. NASA’s Mars Reconnaissance Orbiter relayed images taken by the orbiter’s High Resolution Imaging Science Experiment (or HiRISE) that potentially revealed the Soviet craft’s location in 2007. A group of internet-based Russian Curiosity enthusiasts caught wind of what portion of Mars had been photographed and searched for their lost legacy.

Mars 3 is thought to have landed in the area known as Ptolemaeus Crater (or latitude 45 degrees south, longitude 202 degrees east specifically). Vitali Egorov of St. Petersburg, Russia, knew this. Head of the aforementioned Russian Curiosity group, Egorov used crowdsourcing to enable his subscribers to search the 2007 images for evidence of the lander’s resting place. On December 31, 2012, they did. Or at least, they think they did.

Egorov provided modeling of what certain pieces of the craftâ€"hardware such as the parachute, retrorocket, lander and heat shieldâ€"might look like via HiRISE imagery, and then dispersed the information amidst his investigators. Potential candidates were located in the miniscule details of the southern regions and lay in patterns consistent with entry, descent and landing.

Alexander Basilevsky of the Vernadsky Institute of Geochemistry and Analytical Chemistry in Moscow advises Egorov and his group. He contacted Alfred McEwen, HiRISE Principal Investigator, asking that the region where the suspected remains of Mars 3 were be revisited. McEwen complied, while Basilevsky and Egorov touched base with Russian engineers for more clarification.

New HiRISE images of the area, tailored to highlight the hardware candidates, were received on March 10 of this year. The supposed parachute is consistent with understood measurements (7.5 meters in diameter; a fully spread parachute would measure 11 meters). The other suspected pieces are a retrorocket candidate (complete with chain-like extension, which would have connected it to the lander), one for the lander itself with its four open petals (from which its rover would emerge), and what could be the heat shield (if given that it is partially buried).

NASA does believe the evidence favors the Mars 3 having finally been found, but it cannot yet say for certain.

“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,” said McEwen. “Further analysis of the data and future images to better understand the three-dimensional shapes may help to confirm this interpretation.”