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Eating in Space
Roland Piquepaille writes "What do you think astronauts aboard the International Space Station (ISS) ate for Thanksgiving? Roasted turkey? Wrong answer. In "Orbital Thanksgiving," NASA tells us they had tortillas and gives details about food in space. If the dining view, 200 miles over the Earth, is great, preparing meals is quite a challenge. For example, there is no refrigerator or freezer aboard the Station, so food must remain good for long periods at room temperature. And you need to avoid crumbs which could float around. This is why tortillas are favored over bread. This overview contains additional references and includes a picture of a cosmonaut preparing food in the ISS galley."
I guess they didn't want to mention the Enhanced Gaseous Nitrogen Dewar system, which keeps samples frozen at -321 degrees Fahrenheit...
Or perhaps the ARCTIC freezer system, with 38 liters of -20C degree cold stowage...
ISS Fact Sheets
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Space sure is cold, but there isn't much material to take the heat from you. They really can't freeze things by simply putting them outside the ISS.
I doubt that was their main course. I mean, I live in Mexico, and I like tortillas as much as the Mexicans, especially when they're warm and fresh from the tortillaria. But they hardly qualify as a meal in themselves. I mean, they're made from cornmeal (or flour, if you go for those kind). Surely they had something with their tortillas, like freeze-dried ice cream maybe.
Microgravity is the technical term for the gravity in space. There isnt actually zero gravity, there is always something exerting force on you. The weightlessness comes from being in orbit, not from the lack of any gravity.
I think "free fall" is an acceptable term as well, and describes more accurately the situation. After all, gravity isn't reduced that much in LEO, but staying in orbit really means falling down the horizon.
Maybe we deserve this world ?
Facing a vacuum does not make a freezer. Ever heard of a Dewar (vacuum) flask? I don't know, 19th century technology and already forgotten about in the 21st.
Panurge has posted for the last time. Thanks for the positive moderations.
> And what's this about "no freezer"? What exactly is outer space, if not cold?
Temperature is the mean kinetic energy of particles per volume. Space is quite empty, which keeps the temperature quite low. But, do you know what the best (heat-) insulator is? Vacuum.
What one usually calls "cold" is not something of low temperature, but something with a lower temperature and a good heat conductance. Hence, a piece of metal of room temperature is cold.
It "drains" the heat from you.
"Between strong and weak, between rich and poor [...], it is freedom which oppresses and the law which sets free"
Actually the current state of molecular and cell biology almost makes it possible to grow muscle cells in an organized fashion in a cell culture dish - in other words, growing steaks in the lab. It will definitely be possible to do it for real in a matter of years. Would it be economically viable? Certainly not for a while on Earth, where cheaper alternatives are plentiful - but it could be a solution to avoiding a 100% vegetarian diet on long space missions.
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Hi:
It's the *international* space station. Thanksgiving (as such) was invented in Canada and was a well-established holiday by the time the pilgrims landed in the US.
Regardless, it's a North American holiday. Not everyone in the tin cans spinning above the Earth may have been celebrating it. Of course, it's a US press release, so...
---- The above post was generated by the Turing Institute. Maybe.
The ISS is cooled down by emmitting infrared radiation through gigantic heat sinks that use two closed loops: one with water - to take the heat out of the stations interior and to the heat sinks and the oher with ammonia - to take the heat out of the water and into the heat sink tubing (ammonia freezes at a much lower temperature than water. Water would just become ice and would clog the tubes.) Now THIS is some heat sink that could solve heating problems of a huge super-computer.
I wonder what did MIR use for cooling down?
I like this chronology - a very exciting reading.
You can't handle the truth.
In space, there is much lower background EM depending on whether you are in sight of the sun or not, so for best effect put your "freezer" out behind the ISS away from the sun and I think you'll find that stuff freezes pretty quickly.
Why can't women be like Hedy Lamarr - beautiful, talented and inventors of frequency-hopping spread-spectrum techn
Vacuums are not insulators.
I remember a great demonstration given in the Toronto Science Museum. A piece of rubber tubing placed into a bell jar. A vacuum pump extracting the air until it reached a near-vacuum. Pause... allow air back into the bell jar. Strike rubber with small hammer, rubber shatters and when touched, little pieces of it are _very_ cold indeed.
An object in a vacuum radiates its heat and unless there is an equally warm object radiating heat back, it will cool off until it reaches the temparature of the surrounding radiation, which is (I believe) quite close to absolute zero in darkness, and probably somewhat higher (but nothing like 0 Celcius) in direct sunlight.
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Right. Gravity is actually still quite strong in LEO; the way you maintain orbit is by falling into the gravity well, while having enough 'horizontal' speed so that you're following the curvature where the gravity is the same. Effectively, you're falling toward the ground, but always miss it. You could be in orbit 10m from the ground, assuming you could sustain enough speed in Earth's atmosphere.
You said: "Do you have any idea how fast heat radiation will cool an object in space?"
Stefan's Law states: P = (sigma) * AeT^4, where P is the power radiated, (sigma) = 5.6696 * 10^-8 W/(m^2 * K^4), A is the surface area, e is the emissivity, and T is the temperature (in Kelvin). The emissivity can vary from 0 to 1 depending on the properties of the surface. An ideal absorber, which is also an ideal radiator, has an emissivity of 1 and is known as a black body. So, since an object can both radiate and absorb, its net power is P-net = (sigma) *Ae (T^4 - T-0 ^4) where T-0 is the temperature of the surroundings.
What this means is that your turkey is always going to be radiating a certain value depending on its temperature, but depending on where that turkey is (in the shade behind the spacecraft or in front of the spacecraft receiving radiation from the sun) it may cool down or heat up (if the suns radiation is enough to overcome the heat radiated away). If the turkey stays in one place it will come to equilibrium because eventually the radiation absorbed and radiation emitted will equal out whether or not it heated up or cooled down.
On one side note though, in the case where a turkey is in the radiation stream from the sun, because the radiation from the sun comes from only one direction, one side of the turkey would be much hotter than the other.
Suddenly, the hairy finger of a familiar monkey tapped me on the shoulder. It was time.--G. T.
I recently attended a talk by a NASA education guy on the subject of living in space - on the shuttle and ISS. For the most part, it's really not that different from what you might expect; the main problem is not so much things intrinsic to zero gravity (though there's some of that with liquids, crumbs, etc.) but that NASA generally skimps on the sort of amenities you might think the astronauts could use. For example, there was no "table" on ISS, until the crew up there built one out of some surplus supplies. And, similarly, no refrigerator or freezer. Things will be quite different once the first space hotel goes up.
Energy: time to change the picture.