An improved, lightweight design has been proposed for super-pressure balloons used to carry scientific instruments high in the Earth’s atmosphere for periods of up to 100 days. [A super- pressure balloon is one in which the pressure of the buoyant gas (typically, helium) is kept somewhat above ambient pressure in order to maintain approximately constant density and thereby regulate the altitude.] The proposed design, called “mesh pumpkin”, incorporates the basic concept of pumpkin design, so named because of its appearance (see figure). The pumpkin design involves less weight than a spherical design, and the mesh pumpkin design would further reduce weight.
The basic idea of the pumpkin mesh design is to reinforce the membrane of a pumpkin balloon by attaching a strong, lightweight fabric mesh to its outer surface. The reinforcement would reduce the mass of the membrane to one-third or less of that of the basic Pumpkin design while retaining sufficient strength to allow the balloon to remain at an approximately constant altitude for months.
For example, the pumpkin balloon shown in the figure is made from a complex composite of polyester fabric, adhesive, polyethylene terephthalate film and polyethylene film. The ball has an areal mass density of 62 g/m2 and a total mass of 2,800 kg. The balloon can carry a payload of 1,600 kg at an altitude of 33 km. A matching mesh pumpkin design calls for reinforcement of the membrane with a 1-by-1-in. (2.54 x 2.54 cm) of 25 denier polybenzoxazole scrim fiber mesh (a linear density of about 2.8 mg/m). With this reinforcement, the complex composite membrane could be replaced by a simple 0.5 mil (12.7 μm) thick polyethylene film, reducing the mass of the balloon to
This work was done by Jack Jones and Andre Yavrouian of Caltech for NASA’s Jet Propulsion Laboratory. For more information, access the free online Technical Support Package (TSP) at www.techbriefs.com/tsp under the Materials category.
Pursuant to Public Law 96-517, Contractor has elected to retain ownership of this invention. Inquiries regarding commercial use rights should be directed to
Intellectual Property Group
Mail stop 202-233
4800 Oak Grove Drive
Pasadena, CA 91109
Refer to NPO-21139, volume and number of this issue of NASA Tech Briefs, and page number.
This folder includes a Technical Support Package (TSP).
Mesh Pumpkin Super Pressure Balloon Design
(reference NPO-21139) is currently available for download from the TSP library.
You do not have an account ? Register here.