This artist's scoreboard displays a fictional game between Mars and Earth, with Mars in the lead. It refers to the success rate of sending missions to Mars, both as orbiters and landers. Of the previous 39 missions targeted for Mars from around the world, 15 have been successes and 24 failures. For baseball fans, that's a batting average of .385. The United States has had 13 successes out of 18 attempts, or a “batting average” of .722. NASA's Curiosity rover, set to land on the Red Planet the evening of Aug. 5, 2012 PDT (morning of Aug. 6 EDT), will mark the United States' 19th attempt to tackle the challenge of Mars, and the world's 40th attempt. (Image by NASA/JPL-Caltech)

A soldier poses with a Hythe Mk III Gun Camera during training activities at Ellington Field, Houston, Texas in April of 1918. The Mk III, built to match the size, handling, and weight of a Lewis Gun, was used to train aerial gunners, recording a photograph when the trigger was pulled, for later review, when an instructor could coach trainees on better aiming strategies. (Photo by Harry Kidd/WWI Army Signal Corps Photograph Collection via The Atlantic)

Residents walk past electoral posters in Port-au-Prince, Haiti, January 28, 2017. (Photo by Andres Martinez Casares/Reuters)

In this photograph taken on September 22, 2016, a Pakistani devotee decorates symbolic paper boats, an offering to Muslim saint Abdulqadir Jilani as a way of giving thanks after their desire to give birth to a son was fulfilled, before dropping it into the water during an annual ceremony on the banks of the River Ravi in Lahore. The ceremony commemorates a centuries-old tale that Muslim saint Abdulqadir Jilani raised a sunken ship carrying a wedding party, at the pleading of the groom's mother, saving all the occupants. (Photo by Arif Ali/AFP Photo)

Palestinian man Mohammed al-Hoor, 23, demonstrates his street workout skills in Nuseirat refugee camp, in the central Gaza Strip on May 2, 2017. (Photo by Mohammed Salem/Reuters)

Revelers celebrate during fireworks marking the start of the New Year on Copacabana beach on January 1, 2017 in Rio de Janeiro, Brazil. (Photo by Mario Tama/Getty Images)

Visitors make snowmen beside a pool at a hot spring in Hangzhou, in China's eastern Zhejiang province on January 26, 2018. China's central and eastern regions have been hit by heavy snowfalls in recent days, causing disruptions to flight and train schedules. (Photo by AFP Photo/China Stringer Network)

In this August 24, 2018 photo, Changlair Aristide pauses for a portrait, wearing his protective clothing, including an old U.N. peacekeeper's jacket he found in the trash, before scavenging the Truitier landfill in the Cite Soleil slum of Port-au-Prince, Haiti. Before 2004, Aristide recalled having enough money to splurge on shoes, T-shirts and pants, but this year he could not buy his kids anything new for the school year. “Life is like that, up and down”, Aristide said. “They'll go to school anyway, even if I have to sell my pig. I love them”. (Photo by Dieu Nalio Chery/AP Photo)