High Altitude Balloons

One of the method is using the high altitude balloon. For example to loft sulphates particles, high altitude balloon would disperse sulphate particles in the upper atmosphere. Sulphate particles scatter the sun’s rays back into space, preventing them from reaching earth and so cooling the earth.

High altitude balloon was used in balloon-borne sampling is a highly reliable means to sample air through the entire troposphere and into the lower stratosphere. The system will incorporate a balloon and a flight train of two modules. One module will house an atmospheric sampler. This sampler will be single-stage (samples all particle sizes together), and will place particles directly on an SEM sample stub for analysis. The nozzle depositing the sample will be offset from the center of the stub, placing the aerosol particles toward the edge. At various altitudes, the stub will be rotated 45 degrees, providing 6-8 sample “cuts” of particle populations through the atmospheric column. The flights will reach approximately 27 km altitude, above which the balloons burst and the modules return to the surface. The second module will contain instrumentation recording temperature, pressure, and humidity, plus a radio beacon to track the location, facilitating recovery.

Balloons quite capable of lofting the hose weight. As with pumping, we can choose among several strategies. One extreme is to lift only from the top of the hose, using a single long-duration balloon of 200 meters or more in diameter, flying at an altitude of about 30 kilometers. The hose materials must then have sufficient tensile strength to support the entire system, or must be assisted by additional support cables. Because atmospheric density is low in the stratosphere, the balloon would have to be enormous to develop enough buoyancy. At the opposite end of the range of strategies is an approach in which the hose itself is buoyant, so that every point along its length carries its own weight. In between these two extremes are intermediate strategies that use multiple balloons, each of which support one segment of the hose. This approach allows the balloons to fly over at lower altitudes. The hose itself need to have minimal tensile strength, which translates to lighter weight.

One benchmark that is useful is considering these options are NASA’s long-standing project to develop and demonstrate large, high altitude balloons that are super pressurized with helium. A mission in December 2008 flew one such balloon that was 80 meters in diameter (200,000 m³ volume) to an altitude of 33 kilometers. NASA plans to fly even larger balloons, of over 600,000 m³ volume, in future missions. The NASA balloons are not spherical, but rather are pumpkin-shaped for greater structural efficiency. The envelope has an isotensoid meridional profile and a multi-lobed, azimuthally shape. A thin-walled plastic material both contains the helium and transfers the internal gas pressure azimuthally to the meridional borders of each lobe. Global pressure loads are then handled by strong fibers running along each meridional cusp.