|NASA Goddard Provides a Guiding Hand to the Space Shuttle||
A busy day at Goddard's Flight Dynamics Facility (FDF) usually means something has gone wrong. That's why Jim Cappellari, mission analyst, hopes for a boring day, especially during a Space Shuttle mission.
One busy day came on February 25, 1996, when the Space Shuttle deployed a half-ton satellite attached to a 13-mile tether. Just as the tether was fully extended, it broke. “We then had two objects to track,” Cappellari says.
The tethered satellite experiment was the centerpiece of a project to generate electricity in space. The Space Shuttle was never in danger, but when the chord snapped, scientists thought they lost the multi-million dollar experiment. Goddard tracked the tethered satellite for 48 hours as it moved away from the Shuttle and eventually fell back into Earth's atmosphere. “We didn't think we did anything that extraordinary that day,” said Warren Mitchell, FDF mission coordinator. “A few months after the mission we found out scientists were able to get quite a bit of data because we were able to track the movement of the satellite.”
Goddard's FDF is vital to human space flight operations and the Shuttle’s Return to Flight. Their job is to know at all times where the Space Shuttle is, where it's going and where it could go and pass that information onto NASA's satellite and ground communication network. FDF provides the information necessary to determine the direction communication antennas should point.
Communication antennas don't just automatically lock on the Shuttle and follow the spacecraft where it goes. The communication network has to be updated regularly on Shuttle location. If the flight is routine, the process is almost automatic. If the Shuttle should have to make a maneuver or an emergency landing, there is preprogrammed information in the system. Mitchell says, “We'll send that particular data out and TDRS (Tracking and Data Relay Satellites) will shift its antenna point and then follow the Shuttle.”
FDF spends 80 to 90 percent of their time preparing and practicing for the "what ifs" in Shuttle operations. In addition to emergency landing scenarios, FDF simulates computer failures, power outages and taking over mission control functions if Houston were to have a problem.
If JSC had to evacuate because of a storm or natural disaster during a Shuttle flight, Kennedy Space Center (KSC) becomes Mission Control. Goddard then becomes the primary location for determining where the Shuttle is in its orbit.
Flight directors need to know orbit determination in order to land the Shuttle. “We generate a product every orbit and send it down to the flight dynamics officer at Cape Canaveral,” Mitchell says. “Based on our data, they decide when the Shuttle is going to land.”
Goddard's FDF dedicates three people to space flight operations. Mitchell and Cappellari have worked together for more than 20 years in FDF. Mitchell has worked FDF for every Space Shuttle Mission. Pepper Powers, the youngster of the group is 40 years old. Like Mitchell, he's a mission coordinator. They also support the International Space Station as well as Soyuz launches and landing. During a Shuttle mission, FDF borrows personnel from other parts of their satellite operations to support 24-hour Shuttle operations. For many newer FDF personnel, the Return to Flight mission will be their first Shuttle mission.
Currently, FDF is training and recertifying a new set of mission coordinators. "Even for those that have worked a Shuttle mission before, it's been two years since the last flight," Mitchell says
Mitchell says this Return to Flight reminds him a lot of the first Space Shuttle mission. There's lots of anticipation and waiting. He recalls how mad he was when Columbia's first launch was delayed an entire year because of a tile problem. "You get ready, you ramp up and you wait. Especially after a mission lands ... I remember after STS-1 feeling kind of lost because the next mission wasn't for another six months."
The wait may not be that long this year. While Space Shuttle Discovery has a July launch window, the second Return to Flight mission on Shuttle Atlantis is set for September.
Rani Chohan NASA Goddard Space Flight Center