NASA Spinoff

Inflatable Antennas Support Emergency Communication

Space exploration requires reliable and efficient communication technology. One device currently under development is the inflatable antenna. Due to several unique characteristics—it is lightweight, easy to deploy, inexpensive, and requires low storage volume—inflatable technology is especially well-suited for space applications. Without requiring mechanical actuators or human assembly, something the size of a suitcase could be inflated in space to the size of a basketball court.

In 1960, NASA launched the first of its inflatable space structures in the form of large metalized balloons, the Echo satellites. These were designed to act as communication reflectors to transmit signals from one point on Earth to another. Echo 1A was successfully orbited and was used to redirect telephone, radio, and television signals. Increasingly powerful launch vehicles became available, however, and lightweight inflatable technology was temporarily shelved. In the 1980s and 1990s, interest was renewed due to the cost advantages of the technology, and the space shuttle STS-77 mission successfully deployed an inflatable antenna in space in 1996.

Partnership

With renewed interest brewing in inflatable structures, NASA encouraged further advancements of the technology. ManTech SRS Technologies (formerly SRS Technologies), of Newport Beach, California, received Small Business Innovation Research (SBIR) funding from Glenn Research Center in 1997 to develop an inflatable solar concentrator for power generation. The resulting thin polyimide material used to craft the inflatable concentrator was licensed by SRS and commercially produced as a powder, resin, and rolled film (Spinoff 1998).

It soon became evident that the same basic technology for solar concentrators was applicable for large inflatable antennas, and follow-on SBIR contracts focused on using the polyimide material to develop thin film inflatable antennas for space communication.

Paul Gierow, one of the engineers with SRS at the time, explains, “To make a solar concentrator, you point it at the Sun and focus the energy. The antenna is exactly the same thing, but instead of focusing it on the Sun, you point it at a satellite that is radiating radio frequency (RF) energy. Anything that focuses sunlight energy can typically focus RF energy,” says Gierow.

With the help of SBIR funding, SRS modified the concepts and processes for ground-based inflatable antennas. “We came up with an idea to put an antenna in a ball, or sphere. Intuitively you don’t think it will work, but it did,” says Gierow.

GATR Technologies, of Huntsville, Alabama, was formed in 2004. GATR, which is an acronym for “Ground Antenna Transmit and Receive,” licensed the technology from SRS and has provided additional product refinements leading to a ground-based satellite communications system. The company’s efforts were enhanced by a U.S. Department of Defense award to mature the ground-based antenna system.

To test the new antenna, including testing of the system’s performance for Federal Communication Commission (FCC) certification requirements, GATR entered into a Space Act Agreement with Glenn. As a result, the company gained additional technical understanding of the product and was able to achieve the world’s first inflatable antenna certified by the FCC in 2008. This qualified the antenna for a variety of communication applications within NASA, other government agencies, and commercial entities. That same year, SRS and GATR received the “Tibbetts Award” in recognition of small businesses and SBIR support organizations exemplifying the types of business, economic, and technical development goals of the SBIR program. Popular Science magazine also recognized GATR and designated the inflatable antenna as a “2007 Invention of the Year.” In 2010, the system earned recognition as one of the “R&D 100” (a list of the top 100 inventions of the year), granted by R&D Magazine. Recently, the company entered into a new Space Act Agreement with Glenn to expand the antenna’s frequency range and size, as well as to test and evaluate a larger antenna.