In 2001, NASA’s Space Shuttle will launch satellites created by Virginia Tech undergraduate engineering students.

During fall semester 1998, a team of nine aerospace and ocean engineering (AOE) students drafted conceptual designs for the Virginia Tech Ionospheric Scintillation Measurement Mission (VTISMM) as their senior design project. Their adviser Christopher Hall, assistant professor of AOE, and electrical and computer engineering (ECpE) faculty members Wayne Scales and Warren Stutzman submitted the design to the University NanoSatellite Program, a competitive grant program sponsored by the U.S. Air Force and the Defense Advanced Research Projects Agency (DARPA).

The Virginia Tech project was one of 10 selected nationwide for the $1 million program. Each school will receive $100,000 to construct their satellites and the Air Force and NASA will take care of the launching costs.

Hall said the Tech students will build two basketball-sized satellites, each weighing about five kilograms and containing a computer, power supply, and communications equipment. Orbital Sciences Corp. will provide materials for the satellites. Hall has requested technical assistance for the project from Orbital, the NASA Goddard Space Flight Center, and INTELSAT Corp. The College of Engineering has two laboratories, the Spacecraft Simulator Laboratory and Satellite Tracking Laboratory, that will be used in constructing and operating the satellites.

The project was selected for its scientific and technology demonstration potential, Hall said. The Tech-built satellites will orbit the earth for a month or more, measuring the effects of ionospheric irregularities, or scintillations, on Global Positioning System (GPS) signals. GPS is used for navigation and locating purposes by NASA, the military and aircraft, as well as by millions of individuals. "Even some weapons are guided by GPS now," Hall said.

GPS satellites orbit above the ionosphere, the region composed of layers of earth’s atmosphere ionized by ultraviolet radiation. As GPS navigational signals are transmitted through these ionized layers to receivers on earth, instabilities in the ionosphere cause scintillations in the signals. Problems arise when scintillations cause GPS signals to fade, resulting in errors in navigational signals.

The Virginia Tech satellites will orbit in the ionosphere, taking scintillation measurements that could help scientists and engineers learn how to decrease the effects of irregularities on GPS signals and may add to the body of knowledge about radio wave propagation.

Hall said the students will design two satellites working in tandem because the Air Force and NASA are interested in the concept of launching flying clusters of small satellites in future communications programs. That way, if one satellite fails, the others can continue to carry out their mission. Hall is discussing additional formation flying capabilities with the professors at Utah State University and the University of Washington, who also have received grants under the Nanosatellite Program.

Another new technology that will be demonstrated by the Virginia Tech project is the use of GlobalStar communications satellites. One of the Tech satellites will have a GlobalStar telephone and will be able to place a call to the university for downloading science data.

Most of the original nine students will graduate this May, said Anita Santiago, who chose this as her senior design project because of her interest in space design and her desire to pursue satellite technology as a career. This semester, she said, the seniors are helping to train the underclassmen who have joined the group. The most challenging facet of the project, Santiago commented, has been working as a team toward one unified goal.

Ivan Acosta, who is joining the Air Force after graduation in May and also wants to work with the space program, said the seniors and underclassmen will work this semester to complete the design and get the project ready for the next phase–actually building the satellites.

The AOE and ECpE juniors who are working on the project this semester will help build the satellites during their senior year, Hall said. However, they will have to work on original design projects in addition to the satellites. The best solution? "I think as seniors they’ll design the next generation Virginia Tech research satellites," Hall commented.

The project’s schedule calls for the satellites to be delivered to the Air Force in November 2000. The satellites from all 10 universities will be launched from the Space Shuttle in 2001.