National Aeronautics and Space Administration

Glenn Research Center

James Nessel

June 18, 2013

RF Propagation Studies: Defining Space Communications Architectures for Next Generation Systems

James Nessel is an engineer in Glenn’s Antennas and Optical Systems branch who works with Kaband RF propagation, uplink arrays, and PCB antennas for use in lunar communications.

The lecture started off with an introduction to the Deep Space Network. The Network currently consists of three main dishes in Goldstone, CA; Madrid, Spain; and Canberra, Australia. This network must handle communication up to 1010 km and detect signals with a power on the order of pW to aW. The next generation of the Deep Space Network will use array technology — a system of multiple dishes that combine and enhance the signal together. Such an array combines a large number of smaller dishes; one proposal has a 1 km diameter circle of dishes.

Next, James Nessel described his work with RF signals. A significant problem with these signals is atmospheric attenuation, especially at the 5070 GHz range, due to gaseous absorption, cloud attenuation, and other effects. There are numerous propagation sites throughout the world to study RF attenuation, including a site in Svalbard, Norway, which James helped set up.

James also discussed his path to working at NASA, and how they can help people interested in finishing their education. He earned both his Bachelor’s and Master’s degrees at Arizona State University while doing work with MEMS (Microelectromechanical Systems) with Los Alamos National Laboratories; after joining NASA, his focus changed entirely to communication systems, and that is what he is now studying for his Ph.D. at University of Akron.