Space Shuttle Fuel Cell

CCT Develops Space Shuttle Fuel Cell Telemetry Processing System
Kennedy Space Center, FL

Space Shuttle Mission STS-83 was scheduled for a 16 day Spacelab mission in April 1997 to conduct microgravity research. The mission’s payload, the Microgravity Sciences Laboratory (MSL) carried 19 material science experiments in 4 major Spacelab facilities. A successful mission would build on previous international research missions.

Shortly after launch, however, a problem was detected in an on-board fuel cell. Fuel cell #2, one of three fuel cells on board the space shuttle orbiter, was indicating unusual readings which could require that the fuel cell be shut down, robbing valuable power from the experiments and decreasing the margin of safety for the crew.

NASA was unable to correct the problem on-orbit and was eventually forced to end the mission early, after only 3 days and 23 hours in orbit.

After the mission, NASA decided that a telemetry processing system for critical fuel cell measurements was necessary to provide pre-flight monitoring of the fuel cell systems. This would allow engineers to identify and correct problems with fuel cells early in the processing flow to avoid future costly mission impacts.

CCT senior software engineers were asked to join a team of NASA and United Space Alliance engineers in developing a rapid solution to the problem.

Using commercial off the shelf hardware, CCT developed a telemetry processing unit that accepted the fuel cell telemetry stream, converted that data to a standard shuttle format, and broadcast the data to a network of PC’s that displays the data to shuttle ground engineers.

The software was written in C to run on the VxWorks operating system in a VME based host. The system uses commercial telemetry processing cards manufactured by Berg and standard Motorola processor cards. The system began initial testing in August and is scheduled to support the launch of the STS-87 mission in November.

Command and Control Technologies Corporation specializes in command and control applications for the launch processing and satellite control markets. CCT provides custom solutions by integrating commercial hardware and software with custom software components to provide tailored solutions for our customers. Visit our web site at, e-mail us at, or contact Kevin Brown at (407) 383-5282.


CCT engineers were involved in the development of the following software components:

  • Driver development for the Berg Telemetry board
  • Telemetry interface processing software
  • Measurement processing and formatting software
  • Utilities to monitor the telemetry interface processor
  • Telemetry simulator software used for system integration and test.
  • The software was written in the C programming language to run in the VxWorks real-time kernel environment. Rapid Application Development processes were used to meet the short deadline proposed for integration and support of a November launch date.

The software system is responsible for acquiring the telemetry stream, processing the fuel cell measurements, converting the measurements to shuttle data stream format, and re-transmitting those measurements over an Ethernet network. A series of PC workstations running the PC Ground Operations Aerospace Language environment receive and display the data for use by ground system engineers.


CCT engineers were responsible for the specification, identification, and integration of the hardware components of the telemetry system. The system is VME based and uses commercial telemetry decommutation and processor cards for the downlink processing. The hardware components of the prototype system include:

  • Motorola MVME167 68040 VME Single Board Computer
  • Berg 4422V VME telemetry Interface Card
  • Sun Enterprise server host for VxWorks development tools

CCT specializes in the design, development, and integration of custom telemetry systems for the aerospace community. We are experienced in the products and services of a wide range of vendors. This allows CCT to choose the most appropriate and cost effective solution for telemetry processing problems.

Command and Control Technologies is a high technology developer of command and control systems for the aerospace industry. Contact us at (321) 264-1193 or visit our web site.