they don't have any pro pellant to keep them back up when they come down, right? >> well, there is is nothing to slow them down. if you think about it, the moon doesn't have any propellent either. once you get going fast enough, there is nothing to slow you down or almost nothing. and every few months or so on the space station, we fire the engines just a little bit, the thrusters, just to raise our orbit a little. these little satellites don't have any thrusters. so their orbit will slowly decay and they'll burn up in the upper atmosphere after a couple years. but in their couple years of service, they're about this big, weigh about 10 pounds or so each. they'll map the world, give us -- i can't even count the number of pictures. but just a wonderful way to watch the changes, all of the different types of changes, all the things possible to understand about our planet. but in this case, to help with natural disasters as well as some of the man made disasters that happen. >> commander, this is just so remarkable, this information you're saying we are just on the