From the 1970s? Chewy sticks of goodness, in must-have flavors like chocolate, peanut butter, chocolate mint, and butterscotch (if I recall correctly). Popular during the heyday of space-travel chic in the grocery store, a perfect counterpart to a glass of Tang.
There are places you can buy what purports to be genuine Space Food Sticks, manufactured freshly in the modern day. Word to the wise: Don't buy 'em. They suck. They're shaped wrong. And if the flavor is the same, then I had terrible taste in childhood. Resist the temptation.