CAPE CANAVERAL -- NASA's super-high-flying fleet of communication satellites is about to grow.
An unmanned United Launch Alliance Atlas V 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 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.