Sea Launch User's Guide

Tracking and data
relay satellite system
(TDRSS)
Sea Launch uses a unique dual telemetry stream with the TDRSS. Telemetry
is simultaneously received from the Zenit stages, the Block DM
upper stage, and the payload unit during certain portions of the flight.
The Block DM upper stage and payload unit data are combined, but the
Zenit data is sent to a separate TDRSS receiver. Zenit data is received
shortly after liftoff at approximately 9 sec, and continues until Zenit
Stage 2/Block DM separation, at around 9 min. This data is routed from
the NASA White Sands Ground Station to the Sea Launch Brewster
ground station and to the ACS. The data is also recorded at White Sands
and at Brewster for later playback to the KB Yuzhnoye design center.
When the payload fairing separates, the payload unit transmitter shifts
from sending high-rate payload accommodation data by LOS to sending
combined payload unit/Block DM by TDRSS. The combined data is
again routed from White Sands to Brewster, where it is separated into
Block DM and payload unit data and then sent on to the ACS. The data is
received on board the ship through the INTELSAT communications terminal
and routed to room 15 for upper-stage data and room 94 for PLU
data. Simultaneously, Brewster routes Block DM data to the Energia
Moscow control center. TDRSS coverage continues until after playback
of the recorded Block DM data. Data is also recorded at White Sands and
Brewster for later playback.
Russian tracking
facilities and Moscow
control center
For missions where there may not be adequate TDRSS coverage, Russian
tracking facilities may be brought on line. For low-inclination trajectories,
the Block DM-SL will not be within LOS of the Russian tracking
facilities until it obtains sufficient altitude. When the Block DM-SL is
within LOS of a Russian tracking facility, telemetry is transmitted to the
tracking facility and passed on to the Moscow control center and to the
launch control center on the ACS by way of communication satellites.
Telemetry recorded on board the Block DM-SL is also relayed to the
ground station.
The Zenit’s first and second stages are totally autonomous. A system
called Kvant is also used during the countdown to load the flight data on
board the Block DM-SL. When in view of ground stations, Kvant allows
for an independent orbit determination by comparing uplink and
downlink radio frequency carrier phase shifts. This orbit determination is
separate from the onboard guidance telemetry.
During all phases of launch processing and flight, the launch control
center on the ACS has ultimate responsibility and authority for all decisions
and commands affecting the launch vehicle, Block DM-SL, and the
spacecraft.
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