Ask A Scientist© General Science Archive

name         Heath minix
age          11
       
Question -   Why can't astronauts eat regular food on the moon and all
the other planets?
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Heath,

I think they actually would be able too, and probably would actually enjoy
regular food.  The main consideration with space travel is that there is
very limited space available to take along 'regular food'.  In the past the
freeze dried variety enabled easy tight packing of relatively large
quantites of food in a compact area.  Just add water and voilla! meals ready
to eat.  True, they might be nutritious, but they are not entirely
satisfying.  Recent enhancements to the foods available, for astronauts as
wells as hikers here on earth, for example, include all sorts of what seem
like delicacies by comparison.  So, if you want to become an astronaut, you
can be assured that your meals will more closely resemble at least airline
food, and perhaps somewhat better.

Thanks for using NEWTON!

Richard R. Rupnik 
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name         Heath minix
age          11
      
Question -   Why can't astronauts eat regular food on the moon and all
the other planets?

The main problem for astronauts eating food is gravity, or, more correctly,
the lack of gravity in space.  Nobody is going to the moon any more, and
nobody has ever been to any other planets, so we don't have to worry about
eating there.  So, all we need to worry about now is eating food in a
spaceship, like the Space Shuttle.

Let's think about what "regular food" we eat in a day.  For breakfast, how
about orange juice, toast, and cereal with milk?  For lunch, we'll have a
soda, a peanut butter sandwich, and some potato chips (I said "regular"
food, not "nutritious" food).  For dinner, we'll have peas, mashed
potatoes, and a steak, and ice cream for dessert.

Noe let's think about eating these things without gravity.  How will you
pour the orange juice into a glass?  You might be able to squirt it into a
glass, but it would bounce right out and keep going until it hit something
else.  And if you got it into a glass, how would you get it into your
mouth?  We can solve this problem by putting the orange juice into a
squeeze tube.  then you can just squeeze it into your mouth and swallow
from there.  The cereal with milk will be more of a problem.  How could you
pour the milk into the cereal?  You could try to put both the cereal and
the milk into a bag and shake it to mix them together, but then how would
you get it into your mouth?  If the cereal got really soggy, maybe you
could squeeze it into your mouth, but that probably wouldn't be very easy.
If you tried to spoon it into your mouth, the milk and cereal wouldn't have
any reason to stay on the spoon.  So I think we can forget having cereal
with milk in space.  Next, the toast.  What happens when you eat toast?
Crumbs.  Lots of crumbs.  Here on earth, that's no big deal, because you
have a plate and a napkin to catch crumbs.  In the Space Shuttle, crumbs
wouldn't just fall into your lap.  They would go in every direction, and
get in everything.  So that would be too much of a mess.

How about lunch?  Imagine opening your can of soda in space.  When you open
the can on earth, that puff of carbonation vents into the room.  In space,
the gas "above" the liquid wouldn't be next to the opening; it would be in
a bubble somewhere near the center of the can.  So, when you open the can,
the pressure inside the can would send liquid shooting out of the opening.
So we can forget about soda.  How about the peanut butter sandwich?
Actually, as long as the bread doesn't make many crumbs, a peanut butter
sandwich should work pretty well.  The potato chips would be a problem for
about the same reason as toast: crumbs.  Also, unless you use those potato
chips that come in a can, a package of potato chips takes up a lot of space
for a little food.  There isn't much room in the Space Shuttle, so you
probably wouldn't want to take something that's so bulky.

Now for dinner.  First, the peas.  How will you eat peas?  If you put them
in a cup, how will you get them into your mouth?  If you try to put them on
a fork, they willl probably fly off the fork as you try to get them into
your mouth.  And don't forget that some of the peas would get knocked out
of the cup when you put the fork into them.  Probably the best way to eat
peas in space would be to mash them so that they are sticky, and eat them
with a spoon.  If they stick to the spoon, you don't need to rely on
gravity to keep them there.  What about the steak?  How will you cut it?
If you try to put the steak on a plate, it will float off if you move the
plate or touch the steak.  You can try to cut the steak the same way you
would on earth, by holding the steak against the plate and cutting it with
a knife.  What happens to the piece of steak that you cut off?  You will
probably need three hands , so that you can catch the piece as you cut it
off.  Another way you could try to eat the steak would be to hold it in
your hands and bite off pieces, or cut pieces off with scissors or a knife
while holding the end in your teeth.  This could be quite a mess, as well
as looking pretty uncouth.  It would also increase the chances that you
would cut your lips with the knife or scissors.  And how would you cook a
steak?  You can't just put it in a frying pan;  it wouldn't stay there.
Heat doesn't flow "up" in space, because there's no real "up."  You could
probably microwave things in space, but microwaved steak isn't especially
yummy.  Well, enough about the steak.  How about the mashed potatoes?  This
would probably work in space.  Dried mashed potato flakes would travel well
in a spaceship, and all you'd need to do is mix them with water in a bag,
and then squeeze the potatoes into your mouth.  You could probably even use
a spoon.  Then for the ice cream dessert.  This would probably work if you
had the ice cream on a stick.  In a bowl, it would have some of the same
problems as the cereal with milk.  Dried ice cream has actually been
developed for eating in space;  it tastes like cheap ice cream, but it
isn't cold, and it's crunchy.  Not exactly the normal ice cream experience.

That was just a few examples of the problems you might encounter in trying
to eat "regular food" in space.  If you think about it, you can probably
come up with some other problems you might run into with other foods.  But
you get the idea.

Richard Barrans Jr., Ph.D.      
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