Tomorrow morning, a NASA communications satellite is scheduled to launch to space from Cape Canaveral, Florida, on top of an Atlas V rocket made by the United Launch Alliance. The launch was slated for earlier this month, but was delayed after some equipment on the probe was broken during launch preparations. But now, the satellite, called TDRS-M, is ready to head to orbit, where it will join a fleet of other satellites crucial to NASA’s operations in space.
That fleet is known as NASA’s Space Network — a constellation of satellites that allows the space agency to better communicate with its vehicles in lower Earth orbit. That includes NASA’s many Earth-observing satellites, as well as the Hubble Space Telescope and the International Space Station. Before the network, NASA used to communicate with its orbiting vehicles using only ground-based radio stations — but it came with some time constraints. Fifty years ago, for instance, astronauts could communicate with the ground for only 15 percent of each orbit, according to NASA.
The Space Network, which came about in the 1980s, allows for nearly 24/7 communication. It’s currently made up of around seven active Tracking and Data Relay satellites (TDRS) that sit in a super high orbit, relaying communications between vehicles in lower orbits and stations on the ground. When tomorrow’s TDRS-M launches, it will be renamed the TDRS-13 satellite and be active in the network until the mid-2020s.
The launch of TDRS-M was scheduled for August 3rd, but was postponed after an antenna on the satellite was damaged. At a press conference today, NASA clarified that the antenna was broken when a crane that was preparing to lift the satellite came down and bumped into the satellite. Boeing, the satellite’s manufacturer, had to replace the entire antenna before the launch could take place. When asked if human error or a machine problem was to blame, a representative for Boeing said, “There was no machine problem.”
The antenna is important for getting the TDRS-M into its intended orbit: the satellite is supposed to sit 22,000 miles above the Earth’s surface, but won’t be dropped directly into its orbit by the Atlas V rocket. Instead, it will be deployed into a slightly lower orbit, and then the probe will use its onboard engines to raise itself the rest of the way. During this orbit adjustment, the satellite’s main antenna isn’t always pointed at Earth, so this “backup” antenna is used for communication while the probe gets to where it needs to be.
The Atlas V carrying TDRS-M is scheduled to launch at 8:03AM ET with a 40-minute launch window. It also marks the first launch for the United Launch Alliance so this April. So far, weather is looking pretty good, with an 80 percent chance that conditions will be favorable for a launch. NASA’s coverage of the mission begins at 7:30AM ET. Check back then to watch the launch live.