A United Launch Alliance Atlas V rocket roared to life on the Florida coast this morning. Sitting atop it was NASA’s TDRS-M satellite. It isn’t aiming for another world. Or studying the far reaches of the cosmos. Instead, it’s doing something even more important. Supporting the dozens of NASA missions including the International Space Station and the Hubble Space Telescope.
TDRS stands for Tracking and Data Relay Satellites. First launched in 1983, these satellites fill in the communication gaps that plagued space travel before 1983. Before then, astronauts aboard Skylab and the Space Shuttle could only talk to ground teams when they passed directly over them. That meant communications were only possible for 15% of each orbit.
Today’s launch puts the number of TDRS satellites at ten. Scattered above the Atlantic, Pacific, and Indian Oceans. Across three different radio wave frequencies (S-band, Ku-band, and Ka-band), these satellites uplink and downlink almost all of the mission data and provide important data for navigating these missions in low-Earth orbit. Pictures snapped by the Hubble pass through these satellites and back to Earth. Along with chats between school students and astronauts aboard the ISS.
With the addition of TDRS-M, the batch of satellites will keep supporting NASA missions through the mid-2020s.
“The TDRS fleet is a critical connection delivering science and human spaceflight data to those who can use it here on Earth,” said Dave Littmann, the TDRS project manager at NASA’s Goddard Space Flight Center. “TDRS-M will expand the capabilities and extend the lifespan of the Space Network, allowing us to continue receiving and transmitting mission data well into the next decade.”
Shortly after launch, NASA confirmed the satellite was successfully placed into orbit around Earth. Ground controllers report the satellite is in good health and is beginning a four-month testing phase by Boeing to make sure all systems are go. NASA will carry out their own series of tests with TDRS-M expected to be pressed into service early next year.
The TDRS fleet has proven to be a sturdy one. Since the first one flew into orbit more than 30 years ago, only two have been retired. Five of the nine currently in operation are still kicking past their design life.
These satellites won’t last forever, though. And NASA is already working on their replacement. The radio waves used by TDRS will eventually give way to lasers. While both methods travel at the speed of light, lasers will be able to carry more information. And as the technology for gathering information gets better, the capacity for beaming the data back to Earth needs to get better too.
This upgrade is still a ways off, though. NASA plans to launch the Laser Communications Relay Demonstration in 2019. With lasers, NASA can send 10 to 100 times as much data at a time compared to radio waves. Until lasers are ready for primetime, radio waves will keep being the message bearers for NASA missions.