Blog editor's note: We interrupt this program -- only briefly -- to let all our readers know about a way to send holiday greetings to Sandy and the rest of the International Space Station astronauts. NASA has created a virtual postcard you can send to the astronauts. All you have to do is go to the website, select your postcard (there are four to choose from), then click on it to reverse the card and type your message. It's a simple and easy way to wish the ISS crew happy holidays.