MILLEDGEVILLE — On Thursday night NASA launched the TDRS L communications and data relay satellite. It’s another one of those infamous NASA acronyms, as you can see, but everybody pronounces it “teed-riss”.
Chances are you don’t have a clue what our pal “Teedriss” actually does. Never fear, you’re in good and plentiful company. As its name implies, TDRS satellites are communications relay satellites. They pick up signals from spacecraft out there and pass it on to a receiver on Earth. They are the all-important “middle men”. It would be lovely if every spacecraft could beam its data stream directly to a dish here on Earth. But that’s just impossible, because you don’t always have a ground station in your “line of sight”. And if you do, it’s gone again within minutes or even seconds.
And that’s where the TDRS system comes in. Since it’s a geostationary on-orbit system it has far greater access to ground stations than any deep-space or mission-specific craft, as it is always in connection with several of them, depending on where it is.
TDRS satellites are named in order of the letters of the alphabet. TDRS B was lost when the space shuttle Challenger blew up. All the others made it and hardly ever made the headlines – a fairly common fate of those utilitarian communications workhorses. As older team members drop out of service new replacements are being launched.
TDRS satellites are lifelines between the ISS and Earth, as well as many other spacecraft out there, like the Hubble space telescope. The L spacecraft is a third-generation model, able to communicate with New Mexico’s White Sands facility, bringing yet more flexibility to the network. The next member of this chatty family, TDRS M, is scheduled for launch in 2015.