TDRS 12 is the second replenishment satellite in the third generation of the TDRS system. TDRS 1 to 7 were built by TRW (now Northrop Grumman)
and launched between 1983 and 1995 on the Shuttle. TDRS 8 to 10 were
built using the Hughes HS-601 bus, now the Boeing BSS-601, and launched in 2000-2002.
TDRS 11, 12 and the forthcoming TDRS M use a high power version of the same bus, the BSS-601HP.
The TDRS network receives signals from vehicles like
the space station flying at a mere 250 miles (402 km) and routes the telemetry, voice, video and science information to a dedicated
ground terminal for delivery to Houston.
The satellites incorporate a modern design based on flight-proven performance. The three previous TDRS satellites were based
on Boeing 702-class electronics, which are still the standard for the newest spacecraft Boeing is building today. Additionally,
Boeing has modernized the technologies in the payload, power and propulsion subsystems to current state-of-the-art technologies
being used in other Boeing-built spacecraft.
A pair of 15-foot-diameter, flexible mesh antenna reflectors fold up for launch, then spring back into their original cupped
circular shape on orbit. These steerable, single-access antennas can simultaneously transmit and receive at S-band and either Ku-
or Ka-band, supporting dual independent two-way communication. The selection of Ku- or Ka-band communications is done on the ground.
In addition, an S-band phased array antenna can receive signals from several spacecraft at once, while transmitting to one.
A new NASA Tracking and Data Relay Satellite, TDRS L, was launched on
Jan 24, 2014 by an Atlas V. On reaching operational orbit it was renamed TDRS
12. The TDRS satellites provide space-to-space relays, channelling high bandwidth data from spacecraft to the ground.
On Feb 4, 2014 TDRS 12 was in a 35780 x 35795 km x 7.0 deg inclined geostationary
orbit over 150.0 deg West.