Image via WikipediaSpam in a can (adj.) - Space program slang term for a passive occupant in a spacecraft, specifically a space capsule. The phrase is generally attributed to Chuck Yeagar, if only because he's shown describing the Mercury astronauts as "spam in a can" in the movie The Right Stuff, though there is ample evidence that multiple astronauts and NASA officials used the term liberally during the 1960s Space Race. The early Mercury astronauts, all trained military pilots, are known to have resisted being mere "spam in a can" with no active control of their vessels, thus forcing a level of human direction into early space vehicles.
Spam in a can is now typically used as a snarky criticism of the current level of manned spaceflight technology, as humans are still travelling as meat packed into primitive metal containers and shipped long distances. This falls under the sensawunda criticism of NASA -- particularly the space shuttle successor Project Constellation, which is described as "Apollo on steroids" -- in that we are still not creating or using the sci-fi-inspired tech that books and movies has promised us for decades. Warren Ellis and Colleen Doran rather deftly pointed out the spam-in-a-can disappointment factor with NASA in the graphic novel Orbiter, wherein an alien intelligence redesigns our "primitive" space shuttle into a true interplanetary exploration vehicle.
I bring it up because: Laika passed away 52 years ago on Tuesday. For those that don't know the name, Laika was the first living creature that humans sent into space. She was a Soviet space dog launched aboard Sputnik 2 on Nov. 3, 1957. She died from overheating a few hours after launch, thus making Laika the first spaceflight casualty. Her likeness is preserved in a statue at the cosmonaut training facility in Star City, Russia, as her nation's first space traveler. Telemetry from her mission proved that living beings could survive launch g-forces and weightlessness, thus proving that spam in a can was a viable manned spaceflight model.
I also mention the spam in a can principle as a corollary to Charles Stross's recent thought experiment blog post, How habitable is the Earth? Stross essentially argues that humans are explicitly designed for a particular fraction of Earth's environment that exists during a hyper-minute fraction of Earth's geological history, thus making human space exploration -- which removes us from this environment -- a terribly difficult and expensive undertaking. Karl Schroeder recently counter-argued (the point, not Stross) that most of these problems are surmountable if we get launch expenses down and can get the proper equipment -- all of which already exists -- into orbit cheaply. Which gets us back to the spam in a can criticism: Until the tech gets better, large-scale humans space exploration is a pipe dream.