What does "spam in a can" mean?

From Planet 51:

I never had the right stuff.
I'm a button pusher, Spam in a can.
I don't even fly the ship. It's all automatic.
I only got this far on charm and my rugged good looks.

Is "spam in a can" an idiom? Is it just for space and astronauts etc. or is it a common expression? And what's the exact meaning of it?

Solution 1:

It's what the test pilots of the time called the original American Mercury astronauts, because the astronauts were not really "flying" the craft due to lack of control surfaces or (in the beginning) even windows. "Spam in a can" is heard in the movie version of Tom Wolfe's non-fiction book, The Right Stuff.

Although test pilots at Edwards AFB mock the Mercury program for sending "spam in a can" into space, they recognize that they are no longer the fastest men on Earth, and Yeager states that, "It takes a special kind of man to volunteer for a suicide mission, especially when it's on national TV."

"Spam in a can" is a metaphor evoking the image of the astronauts as nothing but meat in a metal enclosure.

Solution 2:

'Spam' was the brand name of a pork-based luncheon meat launched in the United States in 1937. It was a staple in Britain during the second world war, when food was rationed. It remained for some years after the war an important contribution to the diet.

Perhaps because of its slightly uncertain ingredients, it has often been the butt of comedian's jokes etc.

Wiki has a good article on the subject. http://en.wikipedia.org/wiki/Spam_(food)

Solution 3:

The gist of spam in a can is that the overriding, and possibly only, qualification is being flesh and blood.

For example, where there is far too much data for a human to have any hope of making a reasoned decision, so a computer will be computing all actions (also possible for a remote pilot), but some theory of legal liability requires a human element who can be held responsible for mistakes.

Solution 4:

I believe that spam originally referred to "spiced ham," that is ham in cans using "spices" as a preservative. Coming as it did at the end of the depressed 1930s, it was considered a "delicacy" in its time, and an "inferior good" after World War II, when fresh meat, rather than "canned" meat, became the order of the day.

In modern terms, "spam" refers to "canned" (and usually off-topic) content.

In the passage, the person laments that he is a "canned" pilot for the ship, who "only got this far with my charm and rugged good looks." That's more like "spam," not someone with the "right stuff."