Glenn's Unique Emulation Technology Brings NASA Closer to the Moon

By: Emily Groh

In order to test space networking software, NASA's Glenn Research Center has developed an emulation environment to save both time and money. Otherwise, expensive software and hardware tests would need to be conducted in space to anticipate and troubleshoot issues.

In September 2005, Glenn's Communications, Computing, Electronics, and Imaging (CCEI) Project Office finished its In-space Testbed Project. Through this one-year effort, Glenn utilized its own in-house software to go beyond simulation and emulate a space network using 14 computer systems and customized emulation software for lunar mission planning.

According to In-space Principle Investigator, Thong Luu, Glenn's unique emulation technology will play an important role in future exploration missions to Moon and Mars. Along with significant cost savings, the results of the In-space Project will be used for “development, implementation, and prototyping” in future space networks, he said.

The In-space Testbed consists of 14 computers to represent 3 relay satellites, 1 Crew Exploration Vehicle (CEV), and 1 Moon station. Also, the testbed utilizes three different Deep Space Network (DSN) nodes or Earth stations with large antennas that are located around the world for conducting advanced space network research.

In-space is a continuation of the Space Communication Emulation Facility (SCEF) Project, which began in 2003. SCEF utilized space-based Internet software from the University of Kansas to emulate a satellite network around Earth. With NASA's recent focus on lunar missions, In-space extended the emulation concept to the moon using Protocol Research Emulation Environment (PREE) technology and Glenn's in-house emulation software.

Technology development evolves in several steps: the concept, simulation, emulation, and implementation. Emulation occurs at two levels: software-based and hybrid. Software-based emulation, as used for In-space, operates at a lower level since hardware is not involved. Hybrid emulation utilizes both flight hardware devices (ex: satellite modems or on-board computers) and software.

Emulation is especially important in preparation for a lunar mission so that the long delay (1.5 seconds, each way) that occurs when communicating with the moon can be emulated and further improvements in the infrastructure can be made. In-space utilizes the SCPS-TP (Space Communication Protocol Standard – Transfer Protocol) network protocol to support the long-distance lunar network. With the continued success of Glenn's emulation technology development, NASA is one step closer to reaching its lunar destination and beyond.