Energy comes in many disguises. Everything that does anything uses energy. A car. The Space Shuttle. A tiny spacecraft. You!
For spacecraft, the energy is in the form of electricity and is stored in batteries. The Space Shuttle stores its energy in a device called a fuel cell. For cars, the energy is stored in gasoline. People use their energy to move and breathe and think, and they get their energy from food.
Food is a very good way to store energy. To see how, let's compare how energy is stored and used by automobiles, one particular spacecraft, the Space Shuttle, and children.
Space Technology 5's solar cells produce 24 watts (W for short) of electricity. A watt is a measurement of power, like a pound is a measurement of weight. It takes 2.5 W just for the spacecraft's radio to listen for commands from Earth. If it wants to send a message to Earth, the spacecraft must spend 8 W, one-third of all the energy the solar cells produce. The spacecraft's battery can store 57 watt-hours (W-hr) of energy. This is as much energy as the solar cells produce in 2 hours and 24 minutes. (A watt-hour is the amount of energy in one watt of power working for one hour.)
The spacecraft would need the energy stored in just 4.4 tortillas to operate at full power for an entire day. A person would need to eat 14 to 20 tortillas a day to do the same thing.
The spacecraft is small and must be very thrifty with the energy it has. The 57 W-hr of energy that the battery can store is the same as the energy a human gets by eating just one-half of a tortilla. Food is so good at storing energy that the battery weighs almost 31 times as much as that one-half tortilla! The spacecraft would need the energy stored in just 4.4 tortillas to operate at full power for an entire day. A person would need to eat 14 to 20 tortillas a day to do the same thing!
The Space Shuttle needs much more energy than our little spacecraft. It uses fuel cells to produce 21,000 watts (or 21 kilowatts, kW) of electrical power: 14 kW are used to power the Space Shuttle itself and 7 kW are used to power the Shuttle's payload (the cargo it is carrying to space). The number of tortillas it would take to operate the Space Shuttle is 121 tortillas per hour for the Space Shuttle and 61 each hour for its payload!
An automobile also uses energy. A car that gets 35 miles per gallon is a very thrifty automobile. But that 35 miles per gallon uses the same energy as if that car ate 8-1/2 tortillas every mile that it was driven. At 60 mph, our efficient car would have to eat 508 tortillas every hour!
Energy Used to Operate at Full Power for One Day, Measured in Tortillas
So our little spacecraft gets a lot out of the energy it has, but so do people.
NASA is working on new ways to make spacecraft smaller and more "fuel efficient." The Space Technology 5 mission sent three tiny "nano-satellites" (nano means very, very small) into orbit around Earth. Each spacecraft is about the size of a birthday cake!
And each of the three spacecraft is designed to do its work using less energy than any spacecraft that has gone before. Space engineers in NASA's New Millennium Program developed technologies to miniaturize every part of the spacecraft. This is how they can keep making spacecraft smaller, less expensive, and more able to do many things.Convert a Tortilla!
Now that we've converted tortillas to spacecraft food, it's just one more small step to convert them to spacecraft! After all, you are what you eat, right?
Meet the winners of The Space Place "Tortilla Spacecraft" contest (Sorry, but the deadline is past.)
You can try out their spacecraft designs yourself or make up your own. The idea is to design and build a spacecraft that uses tortillas as its primary building material. You can use tortilla chips too. Other foods may be used for "glue," decoration, scientific instruments, booms, cameras, or other vital structures.
Or, try out one of our winners' tortilla spacecraft recipes. After all, spacecraft get tired of the same old fuel, day after day, just like we do.
The top three entries for both the best tortilla spacecraft design and the best tortilla recipe received U.S. savings bonds: $4,000 for first prize, $2,000 for second prize, and $1,000 for third prize. Prizes were provided by the Tortilla Industry Association.
Also, the first 1,000 people to enter the contest received a set of Space Place Collectible Cards.
Although the contest is over, you can still have fun converting a tortilla!