Where does the Earth’s atmosphere stop and space begin? It is tempting to take the approach Justice Potter Stewart did for pornography when judging a 1964 obscenity case and say “I know it when I see it.” That’s not good enough for scientists, though. The Kármán line is what the World Air Sports Federation (FAI) defines as space. That line is 100 km (62 miles or about 330,000 feet) above sea level. A recent student-built rocket — Traveler IV — claims to be the first entirely student-designed vehicle to pass that line.
The students from the University of Southern California launched the rocket from Spaceport America in New Mexico. The new record is over twice as high as the old record, set by the same team. The rocket reached approximately 340,000, although the margin of error on the measurement is +/- 16,800 feet, so there’s a slight chance they didn’t quite cross the line.