WASHINGTON — The successful launch of a NASA communications satellite Aug. 18 is the final flight of the current generation of data relay spacecraft as well as for a venerable satellite bus.

A United Launch Alliance Atlas 5 401 rocket lifted off from Cape Canaveral Air Force Station at 8:29 a.m. Eastern. The launch was delayed by 26 minutes because of an issue with the temperature on the Centaur upper stage detected during the standard T-4 minute hold.

The Tracking and Data Relay Satellite (TDRS) M spacecraft separated from the Centaur in a geostationary transfer orbit nearly two hours after liftoff. In a statement, NASA confirmed TDRS-M was in good health and in contact with controllers after separation.

The launch, previously scheduled for early August, was postponed by two weeks because of an incident during payload processing that damaged an S-band antenna on the Boeing-built spacecraft. That antenna was later replaced.

During a pre-launch news conference Aug. 17 at the Kennedy Space Center, a Boeing manager said the antenna suffered some “minor damage” when a crane bumped it. “It was prepping to the lift the satellite, and the crane did come down and touch it,” said James Wilson III, Boeing program manager for NASA and civil space programs.

Wilson suggested, but did not explicitly state, that the incident was the result of human error. Asked at the press conference if the crane mishap was a mechanical problem or human error, he said, “There was no machine problem.”

End of the lines

TDRS-M is the third and final satellite in the latest generation of TDRS satellites. Boeing won a contract from NASA for the satellites in 2007 that included two satellites and options for two more. NASA exercised the option for one satellite, but not the other, which would have been TDRS-N.

“The deployment of the satellites depends on the requirements. At this moment, there is no need a TDRS-N,” said Badri Younes, deputy associate administrator for Space Communications and Navigation at NASA Headquarters. “We are seeing a need for additional data relaying capability around the 2025 time frame.”

Those future needs will be met by a later generation of communications satellites. Younes, at the press conference, said those future spacecraft will likely incorporate new technologies, including laser communications, which he said can offer up to 100 times the bandwidth for the same amount of power. “We have declared the next decade to be the decade of light, as we intend to light up the communications highways over the solar system,” he said.

Other technologies he said NASA was considering incorporating on future satellites include disruption tolerant networking and quantum entanglement, which would provide essentially unbreakable encryption for satellite communications. China has been testing quantum entanglement for communications using a satellite launched last year.

Younes suggested that those future data relay satellites might be owned and operated by commercial entities rather than NASA. “NASA’s optimum goal is to push the technology to enable the commercial sector such that these services can be provided by commercial providers, and NASA will not need in the future to build these kinds of capabilities,” he said. “They can become a user, like any other user.”

TDRS-M also marks the end of the line for the Boeing 601 family of communications satellites. The 601 was introduced in 1987 by Hughes Space and Communications, which was acquired by Boeing in 2000. The companies built more than 80 spacecraft using the Boeing 601 bus for commercial and government customers.

“I started out on 601s when I was a young engineer,” said Boeing’s Wilson. “It’s incredibly exciting for me, as an engineer and now as a manager, to have gone through that and see the final launch.”