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It is amazing how time can literally fly in the space business. A little over 2 weeks ago I was sitting in Mission Control watching the Soyuz rocket blast off with two of the Expedition 15 crew members, Fyodor Yurchikin and Oleg Kotov, along with Space Flight Participant Charles Simonyi. I have seen a number of shuttle launches live as well as several Soyuz launches televised. But this one was the most exciting since a crew that I had worked with day to day for almost a year was on that rocket! My wife Dorothy, who accompanied me, also felt the excitement.

Two days later they docked, the crew floated in and the mission was under way. As smooth as it appeared, we were extremely busy on the ground. While a docking might seem “straight forward” or perhaps routine, each one is a little different with unique challenges. For example, when vehicles are docking with the ISS, the solar arrays have to be “feathered” (i.e., the thin side pointing into the direction of the thruster plumes emanating from the approaching vehicle). To maneuver, both the shuttle and Soyuz use gas jets to adjust their trajectory as they approach the ISS. But the chemicals can build up over time and damage the properties of the arrays that allow sunlight to be converted to electricity. Therefore we adjust them to present as little surface area into the exhaust. But this position is not optimal for generating power since the broadest part, the photo cells, may not be directly facing the sun. The amount of power that can be generated depends on the time of year and the space station’s position in orbit, among other factors. Thus each docking is unique. Since the station doesn’t have enough power to run all the equipment, non essential items are turned off to conserve power. This docking proved challenging and we had to power off more than usual, including the Minus Eighty degree Laboratory Freezer for ISS (MELFI), a small refrigerator where a number of medical samples are stored. The MELFI, which uses a great deal of power, cannot be turned off too long before critical science samples are damaged.

In addition, sometimes things go wrong during a docking and the crew has to delay the docking before continuing. If this happens, the power drain on the batteries can be very significant. Too long without enough power to charge the batteries and eventually everything would shut down. To avoid getting in that serious of a situation, the team reviewed what is called a “load shed table” to be prepared to power more equipment off if necessary. Fortunately, things went as well as predicted and we didn’t need this extra power down. Nonetheless, all these plans took a lot of effort from the team.

During the mission, Fyodor and Oleg began to settle in while Misha Tyurin and Mike Lopez-Alegria-- 2 members of the Expedition 14 team -- completed their final packing for their trip home. I am sure it seemed like a whirlwind to them with so much to talk about and explain in such a short time. In Mission Control, we had regular meetings with the Russian flight control team to monitor progress on each day’s activities.

One problem we did have during the mission was that the Cycle Ergometer with Vibration Isolation System (CEVIS) experienced a problem. Exercise is extremely important for the astronauts to help maintain their bone density and muscle strength. Each astronaut exercises about 2 hours a day. It becomes even more critical in the weeks and days before returning to the gravitational pull of the Earth’s surface. Expedition 14 commander Mike Lopez-Alegria was starting one of his exercise sessions when he reported that the tension on the flywheel was not present so there was no resistance when he pedaled. With exercise being an urgent issue, the ground team sprang into action analyzing the problem in an effort to offer a repair. The principle of the CEVIS is much like an exercise bike on Earth (if you ignore the vibration isolation attachments) but it can be challenging to figure out what went wrong with a piece of equipment nearly 200 miles away.

First the engineers who build and oversee the CEVIS as well as the flight controllers got together to try and puzzle the problem out. We listened to the recording of the crew as they called down describing the problem. “Is it making a sound?” “What does the power supply light show?” “What settings were you using?” And so on. Folks who know the software in and out walk through the sequence to see if it could be a software problem. The people who built the equipment develop a “fault tree” listing all possible failures to see if they can eliminate some that do not fit the symptoms. Soon, we develop a trouble shooting plan where we will ask the crew to perform various tests to try and discern the root cause. The flight controller in charge of the system, the Bio Medical Engineer (BME), turns the discussions into a procedure.

The team uplinks the procedure and they execute it the next day. Unfortunately, the news is not good. We will have to ship some new parts to complete fixing. However, they can bypass the electronic system and use CEVIS in a manual mode. Not all the features work in manual mode but they can at least do some biking.

Before I knew it, the mission was over and it was time for Expedition 14 to come home. Just like launch, undocking and reentry are tricky phases. For weeks we have been making plans. Unlike the launch and rendezvous, which takes about 2 days, this phase is a rapid half day.

There is a flight director on console monitoring the progress of the mission. My job is mainly to worry and make sure that the console team has everything they need to ensure the operations go well. I will get busier if something goes wrong. For example, when Expedition 6 returned, their Soyuz reentered in what is called ballistics reentry and the crew landed in a different spot than nominally planned for. In this case, the increment lead focused on the recovery operations while the flight director concentrated on the ISS which is still in space. Everything went smoothly.

But there is no rest for the Expedition 15 crew or the ground control team. A Progress resupply ship is coming in a few days and shortly after that there will be two Russian extravehicular activities (EVAs) or space walks. Back to planning for the next event.

- Bob Dempsey, Expedition 15 Lead Flight Director