Volume 11, Number 2 • Summer 2003 • Small Business/SBIR

AeroAstro Completes Radio Compatibility Testing

AeroAstro, Inc. of Ashburn, VA recently completed successful compatibility testing of its X-Band Transponder with NASA’s Deep Space Network (DSN). The completion of these tests marked a major milestone toward the flight validation of this transponder on the NASA Space Technology 5 (ST5) Nanosatellite Constellation Trailblazer mission, part of NASA’s New Millennium Program (NMP). The two major objectives of the testing were to validate the testing AeroAstro performed by independently assessing the prototype transponder’s performance and to verify its compatibility with the DSN ground system. Included in this testing was the first test of a new DSN uplink command module utilizing direct modulation, one of the elements being implemented to simplify the requirements on transponders
utilizing DSN.

The major facets of the uplink testing included verification of acquisition and tracking, command detection and gain control. The receiver portion of the transponder is capable of tracking greater than ±40 kHz at 5 kHz/sec, 80 dB of linear automatic gain control, and is able to be directly commanded. On the downlink, the 2-watt transmit power and radiated emissions were verified compliant with all DSN requirements.

AeroAstro recently completed fabrication of a prototype of the transponder, and testing this transponder for operability with the DSN, the ground network to be used for the mission, was the next requirement for this flight on the ST5 mission. With the success of the DSN compatibility testing, AeroAstro is beginning the manufacture of a proto-flight unit with identical form and function to the flight units, which are each expected to weigh only 600 grams in an enclosure approximately 6 cm x 6 cm x 9 cm. This full duplex coherent transponder can transmit at a data rate of up to 750 kbps and receive at a rate of up to 4 kbps, with a power consumption of only 10 W for transmit and 4 W for receive. Compatibility testing of the proto-flight unit is scheduled for July 2003, after which flight model fabrication will begin, working toward the ST5 launch planned for 2004.

The NMP ST5 mission consists of three miniaturized satellites that are similar in size to a desktop computer, weighing only about 47 pounds each. These smaller satellites are much easier to manufacture than their large counterparts, bringing down the total mission cost. Flying clusters of multiple smaller satellites rather than a single larger satellite reduces the risk of an entire mission failing if one system or instrument fails. The goal of the ST5 mission is to flight-test its miniaturized satellites and the suite of innovative technologies it incorporates, within the Earth’s magnetosphere, providing data for future development of spacecraft planned to study this region.

AeroAstro began development of the lightweight, compact X-Band Transponder via a 1998 Phase II SBIR award, and the technology was baselined for the Nanosatellite Constellation Trailblazer mission when it was selected for ST5 in 2000. Continued development is funded through a Phase III SBIR award. For its design of miniature X-Band transponders for small satellites, AeroAstro received the prestigious Tibbetts Award in 2000. The X-Band Transponder is just one of many innovative spacecraft systems in development at AeroAstro. AeroAstro manufactures low-cost satellite systems and components used in its own spacecraft and for spacecraft development in the US and abroad. Q

For more information, contact Jim Ramsey at jim.ramsey@aeroastro.com, 703/723-9800, x115. Please mention you read about it in Innovation.

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