By 
NATIONAL HARBOR, Md.—The Space Development Agency (SDA) expects the second launch of Tranche 1 Transport Layer satellites to occur in early October and the current goal is to have the entire constellation of Tranche 1 Transport and Tracking Layer satellites on orbit in the next six to eight months, Gurpartap “GP” Sandhoo, the agency’s director, said on Tuesday.
SDA in July launched its second round of Tranche 1 Transport Layer satellites by York Space Systems [YSS], bringing to 42 the number of data communication spacecraft the company has on orbit for the first tranche. Last fall, the agency launched the first half of Lockheed Martin’s [LMT] planned 42 Transport Layer satellites. Northrop Grumman [NOC] is also under contract for 42 Tranche 1 Transport Layer satellites.
In addition to the 126 Transport Layer satellites designed to provide low-latency communications across much of the globe to quickly alert on missile launches, Tranche 1 will also include 28 Tracking Layer satellites to for missile warning and tracking, and four missile defense demonstration spacecraft.
The Tranche 1 effort is more than a year behind the original plan and Sandhoo said it remains challenged by the same supply chain difficulties, primarily around the Optical Communication Terminals manufactured for the spacecraft, Sandhoo told reporters at the Air Force Association’s Air, Space & Cyber Conference.
The checkout phase for the two York launches—in September 2025 and this July—was two to three times faster the second time around, Sandhoo said. But, on the supply chain, some things have improved and some are unchanged, he said, noting that it is a combination of quality issues and manufacturing throughput.
“The physics requires that we have to have an optical mesh to move this data around,” Sandhoo said. “So, that was not a commodity that was there six years ago. So, it’s new from that perspective. Now some companies have done a decent, better job than others of scaling things.”
Sandhoo highlighted optical heads, focal plane arrays, manufacturing and the need to survive launch as ongoing challenges.
Mesh networking of the Transport Layer satellites on orbit using the laser links has not begun yet, he said. So far, just four satellites have been “pulled into the ground station,” he said, noting that the initial mesh will be within each orbital plane before crosslinks are established between planes.
