jackb, they plan to grow lettuce IN SPACE. Your lettuce takes up SPACE (and such a wise use of that space).
I remember many, many years ago requesting and receiving cabbage seeds for my classroom that were grown and harvested in space, so it is not like they've never done something like this before.
Then there is the difference in cost. How much do you figure a lettuce leaf grown in space would cost when a wrench runs into the thousands of dollars? You get far more food for far less money.
My systems were built from restaurant tubs and small pumps from Harbor Freight for about thirty dollars a unit. I can imagine what they spent on theirs.
Now that you mention it; I did see NASA hit my blog shortly after that little fracus I had with the USDA. Also, they will be growing a variety called Outredgeous, one that I grew and did a post on. Small world is it not?
jackb
I saw a headline about the US space program moving away from a cooperative relationship with Russia and wondered how that was going to work. This lettuce may not just involve nutrition and intrigue but diplomacy!! It's all about being nimble, I'm sure.
If NASA is planning any extended voyages they really should be thinking hydroponics. It is not practical to send tons of soil into space. Anyway, they have lots of money to spend.