Nanotubes are very, very tiny, hollow tubes made of carbon.
That's so small that you can only see them with a very powerful electron microscope . That means you could build some very strong spacecraft and other vehicles that would weigh a lot less than current ones and be more efficient. Nanotubes are also good for electrical purposes. Most wires, like the ones that provide electricity in your home, have something called resistance. As the wires get longer, it gets harder for the electricity to travel through them - the resistance of the wires increases as their length increases.