In this photo posted on Twitter, Sunday, May 3, 2015, and provided by NASA, Italian astronaut Samantha Cristoforetti sips espresso from a cup designed for use in zero-gravity, on the International Space Station. Cristoforetti, the first Italian woman in space, fired up the first espresso machine in space, which uses small capsules, or pods, of espresso coffee. (Photo by AP Photo/NASA)

Throughout the course of the long war in Afghanistan, Coalition troops have relied on thousands of military working dogs to help keep them safe, and make their jobs easier. The dogs are trained to detect explosives, to find illegal drugs, to search for missing comrades, or target enemy combatants. Not only are they active on the front lines, but behind the lines they serve as therapy dogs, service dogs, and loyal companions. They also share the same risks as the ground troops, suffering injuries and sometimes death on the battlefields. Gathered here are images of these dogs and their handlers in Afghanistan and back home, from over the past several years, part of the ongoing series here on Afghanistan.

A Lebanese man carries an injured woman away from the site of a car bomb explosion in a Shiite area and stronghold of the Lebanese militant group Hezbollah at the southern suburb of Beirut, Thursday January 2, 2014. A large explosion has rocked a stronghold of the Shiite Hezbollah group in the southern suburbs of the Lebanese capital. (Photo by Hussein Malla/AP Photo)

An Aden civilian crouching in terror as British soldiers threaten him during Arabian demonstrations in Crater. (Photo by Express Newspapers/Getty Images). 1967

New lovebirds boxer Robin Deakin – once known as “Britain's Worst Boxer” – and former UK “Big Brother” star Lisa Appleton go to the boxing gym in London, United Kingdom on September 28, 2016. The pair were seen holding hands in the street on arrival, and they then slogged it out in the ring and fooled about in Robin's gym. (Photo by FameFlynet UK)

Aeronautics and Space engineer at France's Compagnie Maritime d'Expertises, or Comex, Arnaud Prost (C) meets with a jogger as he tests on the ground the “Gandolfi 2” underwater training suit for spacewalk, on January 20, 2016 in the calanques region (rocky inlets) of Marseille. The underwater training suit “Gandolfi 2”, developed with the European Space Agency (ESA), is designed for training astronauts underwater to simulate space gravity for the astronaut's extravehicular activities (EVAs). (Photo by Boris Horvat/AFP Photo)

A reveler wearing sheepfur costume is seen in front of a bonfire on which they burn a coffin symbolizing winter during the closing ceremony of the traditional carnival parade in Mohacs, 189 kms south of Budapest, Hungary, 07 February 2016. The carnival parade of people, the so-called busos, dressed in such costumes and frightening wooden masks, using various noisy wooden rattlers is traditionally held on the seventh weekend before Easter to drive away winter, and is a revival of a legend, which says that ethnic Croats ambushed the Osmanli Turkish troops, who escaped in panic seeing the terrifying figures during the Turkish occupation of Hungary. (Photo by Tamas Soki/EPA)

A woman plays with a kitten inside of a line house in downtown Shanghai April 12, 2015. (Photo by Carlos Barria/Reuters)