That's interesting and surprisingly long for Kevlar. The highest altitude recorded by a single kite is less than 5km. I understand the biggest constraint for h

That's interesting and surprisingly long for Kevlar. The highest altitude recorded by a single kite is less than 5km. I understand the biggest constraint for higher flights is tether strength-to-weight ratio. Nylon is typically used - fishing line. Tether diameter is another factor as the load from wind, on the tether alone, is considerable over such lengths.