THE PDL STORY
The Ponce De Leon (PDL) Tracking Station occupies 1.4 acres on U.S. Coast Guard property south of the Ponce De Leon Inlet at New Smyrna Beach, Florida, and is part of NASAís Goddard Space Flight Center Spaceflight Tracking and Data Network. The Station is located to provide communications with the Shuttle Orbiter during Launch assent when the Solid Rocket Motor plume blocks radio signals to the MILA Tracking Station at Kennedy Space Center. The operation and maintenance of PDL and MILA are contracted to AlliedSignal Technical Services under Goddard Space Flight Centerís Consolidated Network Mission Operations Support contract.
1979: PDL Station constructed in trailers on U.S. Air Force Eastern Test Range facility on U.S. Coast Guard property.
1981: Began operations to support the first Shuttle mission. Used during all Shuttle launches and 20 Kennedy Space Center landings.
1985: Operations Building constructed.
1986: Microwave Tower constructed along with towers at Shiloh and Wilson to communicate with MILA.
1987: Radome and structure constructed to enclose the S-Band Tracking antenna.
1988: U.S. Air Force Eastern Test Range facility at Ponce Inlet ceases operation.
1992: Power Building constructed to house diesel generators. Fixed UHF cross dipole antenna system installed as backup to S-band/microwave systems.
1995: Discontinued landing support as a budget reduction item.
Current: Digital recorders and video switches installed, beginning the re-engineering project to bring the station under workstation control.
RETURN LINK:- S-Band radio signals transmitted from the Orbiter are received by the 4.3 Meter (15 foot) diameter Antenna (enclosed in a radome) which tracks (follows) the signal. The information on these signals (Astronaut Voice, Orbiter telemetry and Main Engine Data) is then sent via microwave to the MILA Tracking Station at Kennedy Space Center where it is then "best sourced" with MILA data and sent to Mission Control in Houston, Texas.
FORWARD LINK:- Information from Mission Control (voice and commands) is put on a S-Band radio signal and transmitted through the PDL Antenna to the Orbiter. Nominally this forward link is transmitted through this antenna from 1 minute after launch until 2 1/2 minutes. During this time all other transmitting stations are blocked by the Solid Rocket Booster plume (which contains aluminum particles). Since this is the only antenna that can transmit to the Orbiter at this time, the PDL Tracking Station is Mandatory for launch.
BACKUP SYSTEM:- A fixed UHF Cross-Dipole Antenna is available for backup voice communications with the Orbiter. This system can be used in conjunction with return link via the Eastern Range Jonathan Dickerson Instrumentation Facility near Jupiter Inlet, Florida, to provide a backup in case the PDL S-Band system is not operating. PDLís UHF antenna is optimized for high inclination launches. For low inclination launches, UHF via MILA has been demonstrated to be effective.
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