Home on the Range
Sept. 23, 2005
When Discovery landed at Dryden Aug. 9, the Western Aeronautical Test Range staff was ready and waiting to welcome her home.
Image Right: The WATR "antenna farm" is colorful at sunrise. Photo Courtesy Mike Yettaw
Dryden Range Control Officer Dave Jones explained the WATR's role in coordinating Center range assets and personnel with other NASA centers to support several shuttle program areas, including launch, on-orbit requirements and landing.
In fact, Dryden WATR personnel were in position at the Center four hours prior to launch and were communicating with other centers, Jones said. The WATR provides telemetry, radar, voice communication and video support for shuttle flights and the International Space Station to Johnson Space Center, Houston.
"The effort of range support put forth by WATR personnel was extraordinary – crucial for this Discovery mission," said Jan Minniear, WATR business manager.
Data telemetered from the shuttle is usually funneled directly to Johnson through the NASA Tracking and Data Relay Satellite System station located at White Sands Missile Range in New Mexico.
While TDRSS provides the orbiter's primary voice communication link, the WATR facility provides backup communication support for TDRSS should a failure occur during a shuttle mission. The WATR facility was the primary means of communication support when Discovery landed at Dryden.
Flight controllers at Johnson Space Center determined when they would require Dryden's capabilities, which on Discovery's mission was on the third orbit, Jones said. On average it takes 90 minutes for the shuttle to complete an orbit around the Earth, with the first orbit taking up to two hours depending on required maneuvering.
Image Left: WATR communications group members include, seated from left, Tom Barlow, Justin Thomas and Mike Yettaw. Back row, from left, are Richard Batchelor, Doug Boston and Darren Mills. NASA Photo by Tom Tschida
After a schedule of orbit times was established at Johnson, Dryden WATR personnel were given instructions for their role in the mission. During Discovery's 90-minute orbit, Dryden can "see" the orbiter for about six to 10 minutes, depending on its orbit path.
"We were very involved. We had more of a workload (on this mission), including (roles) prior to launch, on orbit and for landing. This mission had us here seven days a week (and for extended shifts)," Jones said.
Discovery's mission was marked by challenges different from those of previous shuttle journeys requiring Dryden's assistance. Deployment of the orbiter's antenna that is required for downlink of video, for example, was delayed; the new robotic arm installed to enable astronauts to examine the orbiter while in space did not permit immediate deployment. So Dryden was tapped to download video used to help mission controllers in Houston monitor the orbiter and its crew.
The WATR telemetry systems provide downlinked orbiter health and status information to Johnson and, when available, the pilot's-point-of-view video that is sent to the NASA network via satellite. When required, the telemetry systems also have the capability to provide uplinked command data to the orbiter.
"That typically is not required, but when the orbiter is in view, we have full support capability with all of our directional antennas pointed at the orbiter," Jones said.
The WATR also tracks the space station from the day prior to launch throughout the shuttle mission, to provide critical docking and undocking information. During docking, Dryden capabilities are tapped to help engineers at Johnson calibrate calculations determining the orbiter's location in relation to the ISS. As the orbiter nears the space station, Jones explained, astronauts can manually control the shuttle through the use of onboard computers, looking out windows to make a safe docking.
To prepare for the Aug. 9 Discovery landing, a process called L Minus 1, which usually occurs a day before landing, is used to check all systems involved in a landing. Dryden's preliminary L Minus 1 happened on Saturday, prior to the Tuesday landing, because Dryden was not asked to be ready for a Monday landing. Kennedy Space Center, Fla., had the first two landing opportunities on Monday, both of which were scrubbed due to weather conditions.
"We check all of the data going back and forth to the orbiter to make sure every system we may have to use is operational," he said.
For Discovery's mission, final checks began at 10 p.m. Monday night.
Image Right: Bob Guere operates the supporting S-band telemetry and downlinked video console, one of many shuttle-related duties for WATR employees. Photo courtesy of Rick Dykstra
"They called us 'green' after the two failed attempts for a Florida landing,'" Jones explained, meaning that flight controllers were calling for a landing at Edwards. "When they called us, everything was already in place."
Dryden's Tracy Ackeret, range control officer, explained the active role WATR personnel had during the Discovery mission.
"We supported 94 orbits with our radars, 132 with our telemetry antennas and at least that many with our communication systems and several orbits with our video support," Ackeret added.
Following the landing, a complex process is required to make the orbiter safe for transport to Dryden's Mate/Demate Device, where a 24-hour, seven-day-a-week umbilical connection to Kennedy via the WATR facilities is activated to allow data gathered during the mission to be transferred electronically.
Range personnel stay sharp through flight-research project support at Dryden, including a mission on the day Discovery landed, said Mike Yettaw, WATR communications lead.
"In addition to the 24-hour Discovery operations, we continued to support all Dryden missions, including the successful, final dual Unmanned Combat Air Vehicle flight," he said.
"Dryden uses the same long-range radio communications systems for both the shuttle and local Dryden flight research mission support. This provides WATR communications (staff) an advantage, in that the local flight support allows us to maintain a high degree of proficiency operating the systems required to support space shuttle operations, including launch, on orbit and landing."
Additional WATR support provided during the landing at Dryden included long-range optical and infrared cameras, video vans for runway video coverage as well as the Mission Control Center that offer key support personnel a location in which to coordinate and monitor landing activities.
Should Dryden experience a commercial power failure during shuttle activities, all crucial WATR areas feature uninterrupted power systems as well as backup generator services. In addition, onsite contractor maintenance personnel monitor the backup systems and provide any emergency services required during critical shuttle operations.