Fuel Cells - A Day in the Life

The space shuttle is the most amazing vehicle ever built. Its capabilities are unsurpassed and its complexity often dazzles even those who work on it. An array of intricate systems come together to make it all possible. One such system is Fuel Cells. From the moment the space shuttle touches down on the runway until the time it once again bathes the launch pad in fire, there are many procedures and tests which need to be done. As soon as the orbiter lands and is later rolled into the Orbiter Processing Facility (OPF), our work begins for its next flight. Our first task is to de-service the vehicle. Basically this means draining all of the cryogenics (liquid hydrogen and liquid oxygen) from our tanks onboard the orbiter. This procedure is quite detailed and can take several days to complete.

Over the course of the next several weeks we perform a variety of tests and checks to make sure our entire system is ready for launch. Many of the checks date the fuel cells themselves. The fuel cells (of which there are three on the orbiter) are the actual units which generate the electrical power for the orbiter. We also perform tests to validate our PRSD system (Power Reactant, Storage and Distribution). This includes the cryogenic tanks and the network of pipes and valves that get our reactants (hydrogen and oxygen) from the tanks to the fuel cells. Other tasks involving the fuel cell system include periodic fuel cell removal and replacement, fuel cell maintenance checks and cryo tank leak checks. Complete electrical checkout of our system also occurs.

In addition, as a member of the Orbiter Group within Fuel Cells there are several more tasks I perform. First, we are responsible for the entire potable water system and waste management system. Since the fuel cells produce pure water as a by product, the water system ties in directly with the fuel cells. During the "orbiter flow" (when the orbiter is in the OPF) we prepare the water to be put on the vehicle. An extensive procedure is performed to make sure the water has just the right amount of chemicals before it is loaded. From loading to launch we periodically sample the drinking water to make sure we stay within our flight limits.

Also tying in with the water system is the waste management system. Post-landing we remove the waste collection system and flush out all of the pipes with an acid mixture. We then install a new one and perform an extensive leak check because this system will be exposed to the vacuum of space. Space suit supply lines are also checked during this procedure.

Even more specifically, I conduct the work on our payload fluid systems. This involves the design, installation, servicing, testing and post-flight removal of this system. The actual configuration will vary from mission to mission. Often cooling, purge, oxygen and nitrogen supply systems are involved. These systems would be the interface between the orbiter and the particular payload we are bringing up to space in the payload bay. The payloads can be as varied as Spacelab (a laboratory for astronauts to work in), the space station docking adapter, very sensitive scientific satellites, replacement parts for the Hubble Space Telescope, along with many other possibilities. Next year we will be integrating the payload support requirements for missions to launch and assemble the international space station.

Three weeks before launch, after the shuttle has been rolled to the launch pad, we connect our launch pad support structure to the orbiter. Approximately 3 days before launch we load our onboard tanks with liquid hydrogen (-423F) and liquid oxygen (-297F). Finally, as launch day arrives we participate in the launch countdown configuring and monitoring our system for launch.

This is a brief overview of the main tasks we are responsible for each flow. In addition, there are many "flight unique" tasks and problems that need to be troubleshooted and performed. Every day is different and the schedule is very dynamic. It really is incredible to realize how much integration, planning and effort it takes to place one of these spacecraft into the heavens. And with four orbiters in the fleet, each in a different state of processing, each day is guaranteed to be a completely new one.

I want to take this opportunity to say thank you to all of you out there who believe in and support the Space Shuttle Program. It is truly a fantastic adventure and is only possible because of your support. No matter if you are sitting in the Firing Room for launch, or you are interested enough to learn more about the program many miles away from Cape, you are an important part of the space program. I appreciate your interest and would be glad to answer any questions you might have.