Digital-Dutch.com Choose altitude and display Temp, Pressure, Density, Speed of Sound
Balloon Flight Calculations:
HABHub.org Burst altitude calculator, Flight Path Predictor, and Live Flight Tracker
3D Parts Design/Gossamer Structure Design an Fabrication
Gotham Machine - I advise projects together with this shop to bring you balloon-optimized 3D printed parts, gossamer carbon fiber structures, tensegrity structures, actuator assemblies, assembly jigs, and more.