12 lbs (in the USA), it has to be two separate payload boxes though (so 6 lbs and 6 lbs). You can launch a lot of equipment with a single weather balloon and a

12 lbs (in the USA), it has to be two separate payload boxes though (so 6 lbs and 6 lbs). You can launch a lot of equipment with a single weather balloon and a styrofoam box. I've been there done that: http://nearspace.0x58.com/ http://nearspace.0x58.com/