Scott Kelly, the NASA astronaut with a green thumb, is hosting Answer Time on Tumblr right from the ISS. What's "Answer Time," you ask? It's like Reddit's AMA where the host fields questions from readers, so if you missed Kelly's AMA earlier this year, now's your chance. Here's a short background on Kelly, in case you're still thinking of what to ask: he's known as the American who has spent the most time in space and is currently on a year-long mission aboard the ISS.
Besides conducting experiments of his own on the space station, he also serves as a subject for NASA's twins study. Scott has a twin brother named Mark who's a former astronaut, and NASA is keeping a close eye on both of them to see what changes a human body goes through during long periods of space travel. You can already submit any question that pops into your head, but Kelly (who's busy doing astronaut things) will only start answering on February 13th, 1:45PM ET.