NASA's super-high-flying fleet of communication satellites is about to grow.
An unmanned rocket is set to blast off Thursday night from Cape Canaveral with the latest, third-generation Tracking and Data Relay Satellite.
NASA uses the TDRS (TEE'-driss) satellites to support the International Space Station and Hubble Space Telescope, among other craft. The network is 22,300 miles high and allows continuous two-way contact with the space station and its six inhabitants.
This newest satellite is designated "L'' in the TDRS series. NASA will rename it TDRS-12 once it's checked out in orbit, by late spring.
The satellite costs about $350 million.
NASA launched its first TDRS in 1983 aboard a space shuttle.
Launch time is 9:05 p.m.
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More information: NASA: tdrs.gsfc.nasa.gov/