Image 1: Apollo 1. This was meant to be the first crewed mission of the Apollo program, but a cabin fire during a launch rehearsal test killed all three crew members: Command Pilot Gus Grissom, Senior Pilot Ed White, and Pilot Roger B. Chaffee (pictured)
Image 2: Challenger. The first fatal accident involving an American spacecraft while in flight. The entire crew was killed: Dick Scobee, commander; Michael J. Smith, pilot; Ronald McNair, mission specialist; Ellison Onizuka, mission specialist; Judith Resnik, mission specialist; Gregory Jarvis, payload specialist; Christa McAuliffe, payload specialist, schoolteacher (pictured)
Image 3: Sputnik 2. Laika was the first living Earthling (other than fruit flies) in space, and her capsule was never designed to come home.
Image 4: Soyuz 11. Georgi Dobrovolski, Vladislav Volkov, and Viktor Patsayev (pictured). The first people aboard a space station, spending 23 days aboard Salyut 1 in 1971. They died tragically on their return to earth when a valve failure caused their capsule to depressurise.
Image 5: Columbia. Space shuttle disintegrated upon re-entry, killing Commander Rick Husband, Pilot William McCool, Mission Specialists Michael Anderson, Kalpana Chawla, David Brown, Laurel Clark, and Payload Specialist Ilan Ramon (pictured).
Image 6: Soyuz 1. The first human death in space. Vladimir Komarov (pictured) was killed when his descent module crashed upon re-entry. It is said that Komarov knew the mission was unsafe, but if he pulled out then they would have sent his friend to die instead: Yuri Gagarin (the first man in space).
Image 7: The Fallen Astronaut. A 3.5-inch (8.9 cm) aluminum sculpture that was left on the moon by the crew of Apollo 15 to commemorate the astronauts and cosmonauts who have died in the advancement of space exploration.